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Composite lattice structures are widely applied in launch vehicles due to their advantages of lightweight and high strength. When they are applied to propulsion systems, compression loads and vibrations must be considered. This study presents a mathematical approach for conducting vibration analysis of composite lattice plates under compressive loads in propulsion systems. This approach relies on a continuous model and the Ritz method and was derived to involve vibrations in a propulsion environment. The proposed method was verified by 3D finite element analysis, and parametric analysis was carried out to explore the impacts of compressive loads on the vibration characteristics. The results provide some general guidelines for the design of composite lattice structures for propulsion systems. [ABSTRACT FROM AUTHOR]

Hybrid double-skin tubular columns (DSTCs) are a promising form of composite columns in which the concrete is sandwiched between inner steel and outer fiber-reinforced polymer (FRP) tubes. A modified form of DSTC incorporating stiffened steel tubes demonstrates more potential benefits than the standard unstiffened design. The inclusion of stiffeners in the steel tube enhances composite interaction among column components, effectively delaying local buckling deformations and potentially improving the behavior of confined concrete. The present study performs both experimental and analytical investigations to measure the impact of stiffeners on the confined concrete behavior of square-circle (SC) configured specimens, considering various column slenderness ratios. Thirty DSTC specimens were experimentally tested with variations in steel stiffener properties, including number, configuration (maintaining a similar combined area), thickness, and width; and unconfined concrete strength. The test results showed a substantial improvement in axial load capacity in the stiffened SC-shaped specimens, reaching up to approximately 37% in this study. Subsequently, the test data were utilized to propose a stress–strain confined concrete model specific to SC-shaped specimens with varying slenderness ratios. This proposed model was employed for calibration study using detailed finite-element (FE) analysis, demonstrating excellent agreement with the test data. A parametric investigation was then conducted through FE analysis to optimize the rib-stiffener properties. Finally, the findings from both the experiments and the FE analysis were utilized to develop a simplified equation that predicts the axial load capacity of stiffened SC-DSTCs. [ABSTRACT FROM AUTHOR]

Polypropylene fiber reinforcement is an effective method to enhance the durability of concrete structures. With the increasing public interest in the widespread use of polypropylene fiber reinforced concrete (PFRC), the necessity of evaluating the mechanism of polypropylene fiber (PF) on the permeability of concrete has become prominent. This paper describes the influence of PF on the concrete permeability exposed to freeze-thaw cycles under compressive and tensile stress. The permeability of PFRC under compressive and tensile loads is accurately measured by a specialized permeability setup. The permeability of PFRC under compressive and tensile loads, the volume change of PFRC under compressive load, and the relationship between compressive stress levels at minimum permeability and minimum volume points of PFRC are discussed. The results indicate that the addition of PF adversely affects the permeability of concrete without freeze-thaw damage and cracks. However, it decreases the permeability of concrete specimens exposed to freeze-thaw cycles and cracking. Under compressive load, the permeability of PFRC initially decreases slowly and follows by a significant increase as the compressive stress level increases. This phenomenon correlates with the volume change of the specimen. The compressive stress level of the minimum permeability point and compressive stress level of the minimum volume point of PFRC exhibit a linear correlation, with a fitted proportional function parameter γ ≈ 0.98872. Under tensile load, the permeability of PFRC increases gradually with radial deformation and follows by a significant increase. The strain-permeability curves of PFRC under loading are studied and consist of two stages. In stage I, the permeability of PFRC gradually decreases with the increase of strain under compressive load, while the permeability increases with the increase of strain under tensile load. In stage II, under compressive load, the permeability of PFRC increases with the increase of freeze-thaw cycles, whereas under tensile load, the permeability gradually decreases with the increase of freeze-thaw cycles. The reduction of PF on the permeability of PFRC under tensile load is greater than that under compressive load. In future research, the relationship between strain and permeability of PFRC can be integrated with its constitutive relationship between stress and strain to provide a reference for the application of PF in the waterproofing of concrete structures. [ABSTRACT FROM AUTHOR]

• The compressive buckling analysis of cracked nanosheets is performed by XFEM, considering small-scale effect. • The contribution of this work is the study of buckling of nanosheets in the presence of a crack. • The studied variables include small-scaling parameter, crack length, nanosheet dimensions, and boundary supports. • The results show that the cracking phenomenon and the increase of its length intensify the nonlocal effect. The process used to produce nanosheets may cause damage such as cracks in them. These cracks can adversely affect the buckling capacity of nanosheets. The main contribution of this research endeavor is to extend the previous studies on undamaged nanosheets to the cracked ones concerning the size-dependent effect. On the nanoscale, the assumption of material continuity, which is the fundamental assumption in classical continuum mechanics, is not valid. In this case, nonlocal non-classical theories are employed to analyze nanosheets. The present paper examines the nonlocal buckling of cracked graphene sheets under uniaxial and biaxial loads. To this end, the governing equations are developed based on the first-order shear deformation theory and using Eringen's nonlocal elasticity theory. Moreover, cracked nanosheets with various boundary conditions are analyzed via the extended finite element method. The variables under study are the small scaling parameter, crack length, nanosheet dimensional parameters, and support conditions. The results indicate that while the small scaling parameter reduces the critical buckling capacity of nanosheets, the presence of a crack in the nanosheet and the increase in its length intensify the nonlocal effect. In addition, as the aspect ratio of the nanosheet increases from one, the nonlocal effect decreases gradually. The small-scale effect increases by constraining the edges of the cracked nanosheets. [ABSTRACT FROM AUTHOR]

Abstract Carbon fibre-reinforced polymer (CFRP) plates can efficiently repair or enhance the mechanical properties of the square hollow section. However, the loading end of such a CFRP-strengthened member is prone to local bearing failure under compressive load. Given this limitation, an innovative CFRP-plate-strengthened square hollow section composite member (CFRP-SHSCM) was raised, and the thick-walled section was welded on both ends of the thin-walled steel column. The mechanical properties of CFRP-SHSCMs were investigated through parameter finite element (FE) analysis, focusing on the influence of the amount of CFRP layers (n c ), the slenderness ratio (λ), the initial geometric imperfections (v 0 ), the CFRP layouts (2S and 4S) and the length of the exposed steel column (L e ). The load–displacement curves, the bearing force, and typical failure modes were also acquired. Results indicated that with increasing n c and v 0 , and decreasing λ, the conventional CFRP-SHSCMs were prone to local bearing failure with poor ductility, leading to the insufficient use of the CFRP plate, in contrast, the improved CFRP-SHSCMs primarily underwent overall buckling failure and exhibited better bearing force and ductility. Finally, the modified Perry-Robertson formula was put forward to predict the ultimate load of the CFRP-SHSCMs. The coefficients of variation between the FE simulation and the theoretical results were 0.00436 and 0.0292, respectively.

Carbon fibre-reinforced polymer (CFRP) plates can efficiently repair or enhance the mechanical properties of the square hollow section. However, the loading end of such a CFRP-strengthened member is prone to local bearing failure under compressive load. Given this limitation, an innovative CFRP-plate-strengthened square hollow section composite member (CFRP-SHSCM) was raised, and the thick-walled section was welded on both ends of the thin-walled steel column. The mechanical properties of CFRP-SHSCMs were investigated through parameter finite element (FE) analysis, focusing on the influence of the amount of CFRP layers (nc), the slenderness ratio (λ), the initial geometric imperfections (v0), the CFRP layouts (2S and 4S) and the length of the exposed steel column (Le). The load–displacement curves, the bearing force, and typical failure modes were also acquired. Results indicated that with increasing nc and v0, and decreasing λ, the conventional CFRP-SHSCMs were prone to local bearing failure with poor ductility, leading to the insufficient use of the CFRP plate, in contrast, the improved CFRP-SHSCMs primarily underwent overall buckling failure and exhibited better bearing force and ductility. Finally, the modified Perry-Robertson formula was put forward to predict the ultimate load of the CFRP-SHSCMs. The coefficients of variation between the FE simulation and the theoretical results were 0.00436 and 0.0292, respectively. [ABSTRACT FROM AUTHOR]

Various mechanical parts come into high-load rolling and sliding contact at the contact surface. Even with technological advancements, mechanical failures still occur. Rolling-sliding mechanical contact issues are the primary cause of over 90 % of surface and subsurface metallic failures and they are only becoming worse. Using discretised continuum 2D finite element methods (FEM), this research investigates the parametric contact effect of a steel twin disc system subjected to rolling-sliding contact at varied surface friction and comprehensive load condition. The equivalent von Mises stress distribution, contact pressure distribution and shift position of maximum subsurface stress on the contour region are all influenced by changes in compressive load and coefficient of friction, according to a numerical surface-to-surface contact simulation performed with Abaqus at mean Hertzian pressure. The maximal equivalent stress, for a given load, reaches a peak in the subsurface and moves farther away from the surface when the coefficient of friction decreases and comes close to the contact surface when the coefficient of friction increases. Consistency is shown by the analytical and numerical results.

Polypropylene fiber reinforcement is an effective method to enhance the durability of concrete structures. With the increasing public interest in the widespread use of polypropylene fiber reinforced concrete (PFRC), the necessity of evaluating the mechanism of polypropylene fiber (PF) on the permeability of concrete has become prominent. This paper describes the influence of PF on the concrete permeability exposed to freeze-thaw cycles under compressive and tensile stress. The permeability of PFRC under compressive and tensile loads is accurately measured by a specialized permeability setup. The permeability of PFRC under compressive and tensile loads, the volume change of PFRC under compressive load, and the relationship between compressive stress levels at minimum permeability and minimum volume points of PFRC are discussed. The results indicate that the addition of PF adversely affects the permeability of concrete without freeze-thaw damage and cracks. However, it decreases the permeability of concrete specimens exposed to freeze-thaw cycles and cracking. Under compressive load, the permeability of PFRC initially decreases slowly and follows by a significant increase as the compressive stress level increases. This phenomenon correlates with the volume change of the specimen. The compressive stress level of the minimum permeability point and compressive stress level of the minimum volume point of PFRC exhibit a linear correlation, with a fitted proportional function parameter γ ≈ 0.98872. Under tensile load, the permeability of PFRC increases gradually with radial deformation and follows by a significant increase. The strain-permeability curves of PFRC under loading are studied and consist of two stages. In stage I, the permeability of PFRC gradually decreases with the increase of strain under compressive load, while the permeability increases with the increase of strain under tensile load. In stage II, under compressive load, the permeability of PFRC increases with the increase of freeze-thaw cycles, whereas under tensile load, the permeability gradually decreases with the increase of freeze-thaw cycles. The reduction of PF on the permeability of PFRC under tensile load is greater than that under compressive load. In future research, the relationship between strain and permeability of PFRC can be integrated with its constitutive relationship between stress and strain to provide a reference for the application of PF in the waterproofing of concrete structures.

The combination of environmental actions and mechanical load, which most structural concretes are subjected to, has a synergetic effect on the durability of concrete. The comparative test conducted by RILEM TC 281-CCC WG4 demonstrated and quantified the effect of an applied mechanical load on carbonation performance of concrete with supplementary cementitious materials. Although the effect of loading on the chemical durability of concrete should be taken into consideration for the development of realistic service life predictions, they have been widely overlooked so far. This recommendation proposed by RILEM TC 281-CCC WG4 proposes a testing method for determining the effect of applied load on the carbonation rate of concrete. It specifies a detailed experimental procedure to determine the carbonation development of concretes subjected to compressive and tensile loads. Therefore this recommendation will support the consideration of such combined effects in design codes. [ABSTRACT FROM AUTHOR]

This study investigates the performance of granular anchor piles and helical piles in expansive soils. Expansive soils pose challenges for engineering due to their significant swelling and shrinkage characteristics. Special considerations are required for constructing foundations on expansive soil to mitigate volumetric changes. While helical piles provide uplift resistance in light structures, they may not fully stabilize foundations in expansive soils. In contrast, granular anchor piles offer a simpler alternative for resisting uplift forces. A numerical study was conducted to analyze the pullout loads, compressive loads, and heave behavior of these anchor techniques. The results demonstrate that granular anchor piles outperform helical piles in terms of pullout and compressive performance, with improvements ranging from 17% to 22.5% in pullout capacity and 0.5% to 19% in compressive capacity, depending on specific pile lengths and diameters examined. However, both techniques show similar effectiveness in reducing heave, achieving reductions of over 90% when specific conditions are met. Additionally, the use of high-rise cap piles contributes to significant heave reduction, effectively minimizing heave to nearly negligible levels compared to low-rise cap piles. It is found that the relative density of the granular material has a more pronounced effect on the pullout load compared to the compressive load, and its impact varies depending on the length of the pile. Therefore, it is recommended to avoid high relative density when the pile is entirely within the expansive soil while utilizing higher relative density is beneficial when the pile penetrates and settles in the stable zone. [ABSTRACT FROM AUTHOR]

This paper presents the results of static and dynamic tests of fiber-reinforced and unreinforced concrete samples under laboratory conditions. Concrete samples reinforced with steel and non steel fibers were tested. The dynamic tests were carried out on the stand by applying falling weight impacts on the concrete samples. The impact testing of samples included two stages of deformation: until the first defects appeared in the samples and until their complete destruction. The impact resistance of the samples was evaluated according to the energy input of the hammer with registration of the type, size and volume of the defects. It was revealed that the type of fibers has a different effect on the static and impact resistance of fiber concrete. Correlational dependencies used for predicting the strength and energy parameters of fiber concrete in their comparative evaluation have been obtained. It has been determined that the static strength and impact resistance of fiber concrete may not be identical, i.e., a high static strength in fiber concrete does not always provide a high impact resistance. The impact resistance of fiber concrete when tested before the first defects appear is always lower than when tested before complete failure. [ABSTRACT FROM AUTHOR]

Mechanical overload is considered the main cause of Achilles tendinopathy. In addition to tensile loads, it is believed that the Achilles tendon may also be exposed to compressive loads. However, data on intratendinous pressures are lacking, and consequently, their role in the pathophysiology of tendinopathy is still under debate. Therefore, we aimed to evaluate the intratendinous pressure changes in the Achilles tendon during stretching and eccentric loading. Twelve pairs of human cadaveric legs were mounted in a testing rig, and a miniature pressure catheter was placed through ultrasound‐guided insertion in four different regions of the Achilles tendon: the insertion (superficial and deep layers), mid‐portion, and proximal portion. Intratendinous pressure was measured during three simulated loading conditions: a bent‐knee calf stretch, a straight‐knee calf stretch, and an eccentric heel‐drop. It was found that the intratendinous pressure increased exponentially in both the insertion and mid‐portion regions of the Achilles tendon during each loading condition (p < 0.001). The highest pressures were consistently found in the deep insertion region (p < 0.001) and during the eccentric heel‐drop (p < 0.001). Pressures in the mid‐portion were also significantly higher than in the proximal portion (p < 0.001). These observations offer novel insights and support a role for compression in the pathophysiology of Achilles tendinopathy by demonstrating high intratendinous pressures at regions where Achilles tendinopathy typically occurs. To what extent managing intratendinous pressure might be successful in patients with Achilles tendinopathy by, for example, avoiding excessive stretching, modifying exercise therapy, and offering heel lifts requires further investigation. [ABSTRACT FROM AUTHOR]

An experimental investigation is carried out to evaluate the ultimate compressive capacity of welded stiffened aluminum panels in alloy 5083-H116 subjected to uniaxial compressive load along the short edge. A tensile test is carried out to find out the real material properties. Five full-scale stiffened panel specimens, one of them is intact and locked cracks are produced in the other four panels. A global survey of the initial geometric imperfections is performed before conducting the compressive test. Through-thickness locked cracks are located either in the center or quarter of the plate between the two attached stiffeners. The panels are tested, and their progressive collapse behavior is reported. The panels failed by two different deformation modes: stiffener tripping and local buckling of the plate. The load-shortening and load-lateral displacement relations are presented, and concluding remarks are stated regarding the effect of locked crack’s location, orientation and initial imperfection on the compressive capacity of welded aluminum panels.

This work reports the investigations of the electric potential impacts on the mechanical buckling of the piezoelectric nanocomposite doubly curved shallow shells reinforced by functionally gradient graphene platelets (FGGPLs). A four-variable shear deformation shell theory is utilized to describe the components of displacement. The present nanocomposite shells are presumed to be rested on an elastic foundation and subject to electric potential and in-plane compressive loads. These shells are composed of several bonded layers. Each layer is composed of piezoelectric materials strengthened by uniformly distributed GPLs. The Halpin–Tsai model is employed to calculate the Young's modulus of each layer, whereas Poisson's ratio, mass density, and piezoelectric coefficients are evaluated based on the mixture rule. The graphene components are graded from one layer to another according to four different piecewise laws. The stability differential equations are deduced based on the principle of virtual work. To test the validity of this work, the current mechanical buckling load is analogized with that available in the literature. Several parametric investigations have been performed to demonstrate the effects of the shell geometry elastic foundation stiffness, GPL volume fraction, and external electric voltage on the mechanical buckling load of the GPLs/piezoelectric nanocomposite doubly curved shallow shells. It is found that the buckling load of GPLs/piezoelectric nanocomposite doubly curved shallow shells without elastic foundations is reduced by increasing the external electric voltage. Moreover, by increasing the elastic foundation stiffness, the shell strength is enhanced, leading to an increase in the critical buckling load. [ABSTRACT FROM AUTHOR]

Present paper has experimentally and numerically investigated the mechanical behavior of composite sandwich panel with novel M-shaped lattice core subjected to three-point bending and compressive loads. For this purpose, a composite sandwich panel with M-shaped core made of carbon fiber has been fabricated in this experiment. In order to fabricate the sandwich panels, the vacuum assisted resin transfer molding (VARTM) has been used to achieve a laminate without any fault. Afterward, polyurethane foam with density of 80 kg/m3 has been injected into the core of the sandwich panel. Then, a unique design was presented to sandwich panel cores. The study of force-displacement curves obtained from sandwich panel compression and three-point bending tests, showed that an optimum mechanical strength with a considerable lightweight. It should be noted that the experimental data was compared to numerical simulation in ABAQUS software. According to the results, polyurethane foam has improved the flexural strength of sandwich panels by 14% while this improvement for compressive strength is equal to 23%. As well as, it turned out that numerical results are in good agreement with experimental ones and make it possible to use simulation instead of time-consuming experimental procedures for design and analysis. [ABSTRACT FROM AUTHOR]

Truss‐like core sandwich panels made of glass fiber‐reinforced polymer (GFRP) composite are extensively exploited in numerous industrial and non‐industrial applications. Most of the time, these structures are exposed to extreme and heavy loads and damaged. Therefore, the mechanical properties of composite sandwich structures are important issue that should be addressed by engineers. For this purpose, the mechanical properties of a GFRP composite sandwich structures with polyurethane foam‐filled M‐shaped core are numerically and experimentally determined in this research. The sandwich panels manufactured for this study are composed of GFRP as fibers and resin epoxy as matrix material. In order to determine the bending and compressive response of the GFRP composite structures, three‐point bending and compression tests are performed using a SANTM ATM‐140 universal testing machine. A finite element method is developed to validate the precision of the experimental results. It is recognized that the finite element data are in remarkably great agreement with those obtained by experimental tests. Hence, the finite element analysis and experiment method could be utilized to predict the mechanical properties of the GFRP composite sandwich panels. [ABSTRACT FROM AUTHOR]

A type of cellular foam concrete called lightweight concrete is made of cement paste or mortar with air spaces or structural pores created by the use of a foaming agent. Examining the crack pattern of lightweight concrete under compressive and tensile loads is the goal of this study. A lightweight concrete specimen was made using foam, fine aggregate, and Portland Composite Cement. Foam agent and water are combined in a 3:10 ratio to produce foam. There were three different foam volume variants used: 15.7 liters, 25.12 liters, and 37.68 liters. As a sample, a cylinder with dimensions of 10 cm by 20 cm was employed. Using compressive and indirect tensile strength tests at curing ages of 3, 7, and 28 days, the crack pattern of lightweight concrete was assessed. The findings revealed that the fracture pattern for the compressive and indirect tensile strength tests was almost same; because the crack pattern was parallel to the direction of the load, it was categorized as a columnar crack pattern at 3, 7, and 28 days. Throughout time, the frequency of crack patterns in lightweight concrete decreased. It might be said that concrete becomes more resistant as it ages. [ABSTRACT FROM AUTHOR]

The present research has addressed the flexural and compressive strength of Kevlar fiber composite sandwich panels with novel lattice core, experimentally and numerically. The composite sandwich panels and corrugated cores have been made using the vacuum-assisted resin transfer molding method. Afterward, compressive and three-point bending loads were applied to the composite sandwich panels to determine mechanical performance during structural deformation. Scanning electron microscopy has been conducted on the specimens to evaluate the Kevlar-fiber distribution. In order to evaluate the experimental results, the corresponding testing process has been numerically simulated through finite element analysis. It has been figured out that the simulated model can predict the force–displacement response of the considered sandwich panels under bending and compressive loads. Finally, the effect of polyurethane foam on the composite sandwich panel's mechanical strength and energy absorption capacity has been investigated. [ABSTRACT FROM AUTHOR]

Packers are downhole equipment that is essential equipment in well workover operations to protect the production string from reservoir pressure. The sleeve assembly, which is the main assembly of the packer, requires that during setting the packer is not damaged and does not stick to the inside of the well when running into the well, and that the packer is set correctly. When mounting the packer in the well, it is necessary to ensure full balance. To ensure balance when setting the packer, in workover wells, care must be taken to ensure that the packer is lowered into the well at low speed. When lowering the packer into the well, it is also necessary to control the descent speed and know the pattern of change in the dependence of the dynamic force on the descent speed. The calculation of the allowable compressive load on the packer equipment used in well repair is considered. A stability criterion is proposed that takes into account bending stresses that occur when a packer is mounted in a well. Depending on the diameter of the tubing, the critical value of the compressive force acting on the packer was determined, and a new expression was obtained for calculating the allowable load acting on the packer used in the repair well. The critical compression force was calculated depending on the diameter of the well pipes. Depending on the diameter of the tubing, the numerical values of the critical force on the packer were determined. It was found that the value of bending stresses as a criterion for static stability corresponds to 15 % of the yield strength when the packer is mounted in a repair well. When mounting the packer in repair wells, care must be taken to ensure that the packer is lowered into the well at low speed to ensure balance. [ABSTRACT FROM AUTHOR]

The determination of the engineering properties of the cashew nut is essential as the basis for the design and development of appropriate and optimum post-harvest handling and processing machinery. The present study examined the physical, mechanical and colour properties of cashew nuts (n = 100) at a moisture content of 7.63% (wet basis) derived from Central Java, Indonesia. The main characteristics included the length, width, thickness, mass, volume, and density. The derivative properties consisted of the geometric diameter, arithmetic diameter, surface area, frontal surface area, transverse area, shape index, sphericity, bulk density, and porosity. The mechanical properties included the static friction, static and dynamic angle of repose, and compressive load (in four orientations). It was identified that the cashew nut from Central Java was dominant with a small-medium size with an average mass of 5.42 ± 0.99 g. This cashew nut was thicker, but shorter in length than the cashew nuts from India, Nigeria, and Ivory Coast. The results of the stepwise regression analysis determined that the volume had the most substantial relationship with the mass (R2 = 0.949), the bulk density had the highest correlation with the mass (R2 = 0.968), and the porosity showed a high correlation with the true density and mass (R2 = 0.997). The highest friction, static angle of repose, and-dynamic angle of repose occurred on the surface plywood, and the lowest was on the stainless-steel surface. In the context of designing appropriate cashew nut cracking equipment, it was recommended to provide the impact parallel to the longitudinal axis orientation due to the minimum compressive load (reduce the power requirement). Furthermore, the cashew nut colour properties of the L*, a*, b* coordinates were 35.988, 0.427, 1.718, respectively.

An offshore aluminum floor structure made from inverted T-shaped beams and a transversely stiffened deck was investigated experimentally and numerically. The deck assembly contained weld-connected extruded profiles with a closed trapezoidal stiffener and flat plating, which constituted the beams' top flange. A bending test was designed to produce a state of pure axial compression perpendicular to the stiffeners in the deck without the influence of transverse loading on the deck. The compressed floor deck developed buckling deformations where the deck profiles/stiffeners deflected elastically with alternating upward/downward buckling bows between the floor beams, occurring at an average membrane compression stress of 30 N/mm2 in the deck plate. Ultimately, the average membrane stress was 54 N/mm2, and the deck stiffener deflections were >10 mm. The compressive deck plate stresses gradually redistributed to the regions near the webs of the floor beams, where failure occurred by inelastic buckling of the deck plate. FE simulations accurately reproduced the bending resistance of the floor structure, the observed buckling forms and displacements in the deck, and the strain and stress distributions in the deck plate. The existing design provisions for compressed transversely stiffened plates are insufficient and provide capacities less than half of that from the experiment. • An experiment for a stiffened floor deck in transverse compression was presented. • Stiffener deflections and deck plate buckling occurred in the specimen. • Stress redistribution and post-buckling capacity were observed. • Modeling options for the stiffened deck and various capacity models were studied. • Capacity predictions by various methods were found conservative. [ABSTRACT FROM AUTHOR]

Plenty of soft inclusions such as micro pores and micro cracks are commonly distributed in concrete. Figuring out the generation and propagation of micro cracks in concrete is of great significance to the detection and evaluation of initial damage in concrete. Second harmonic generation method is more sensitive to the micro damage in concrete. However, the study of the regularity of nonlinear ultrasonic during crack propagation is rare and insufficient. Therefore, the integrity of concrete specimens was first verified by observing the microscopic morphology of the samples using scanning electron microscopy (SEM). Then a simultaneous test system for stress, strain and nonlinear parameters was designed to investigate the regularity of the nonlinear parameter β during the compressive loading. The results show that the nonlinear parameter β increases significantly at the beginning of loading. With the increase of the compressive load, the nonlinear parameter β decreases rapidly, and fluctuates during the subsequent loading. Compared with the first wave amplitude A, it is proved that the nonlinear ultrasonic parameter β is more sensitive to the initiation and accumulation of the micro damage in concrete, and the first wave amplitude A has a better regularity to the later elastic stage and the plastic stage in concrete. [ABSTRACT FROM AUTHOR]

The determination of the engineering properties of the cashew nut is essential as the basis for the design and development of appropriate and optimum post-harvest handling and processing machinery. The present study was conducted to examine the physical, mechanical and colour properties of cashew nuts (n = 100) at a moisture content of 7.63% (wet basis) which were derived from Central Java, Indonesia. The main characteristics included the length, width, thickness, mass, volume, and density. The derivative properties consisted of the geometric diameter, arithmetic diameter, surface area, frontal surface area, transverse area, shape index, sphericity, bulk density, and porosity. The mechanical properties included the static friction, static and dynamic angle of repose, and compressive load (in four orientations). It was identified that the cashew nut from Central Java was dominant with a small-medium size with an average mass of 5.42 ± 0.99 g. This cashew nut was thicker, but shorter in length than the cashew nuts from India, Nigeria, and Ivory Coast. The results of the stepwise regression analysis determined that the volume had the most substantial relationship with the mass (R2 = 0.949), the bulk density had the highest correlation with the mass (R2 = 0.968), and the porosity showed a high correlation with the true density and mass (R2 = 0.997). The highest friction, static angle of repose, and-dynamic angle of repose occurred on the surface plywood, and the lowest was on the stainless-steel surface. In the context of designing appropriate cashew nut cracking equipment, it was recommended to provide the impact parallel to the longitudinal axis orientation due to the minimum compressive load (reduce the power requirement). Furthermore, the cashew nut colour properties of the L*, a*, b* coordinates were 35.988, 0.427, 1.718, respectively. [ABSTRACT FROM AUTHOR]

A similar theoretical approach is generally used to estimate the end-bearing capacity of straight and screw piles. However, under similar ground conditions (stress level and bearing-capacity factor) and pile tip area after the pile is installed, the end-bearing capacity of the screw pile is less than the straight pile. In this study, the experimental tests were modeled in a three-dimensional (3D) finite-element code to better understand the pressure distribution and mobilized shear strength under straight and screw piles embedded in similar ground conditions. Moreover, the effect of helix position on the pile bearing capacity and pressure beneath the helix and shaft of the screw pile was also investigated. A helix-to-shaft diameter ratio (Dh/DSS) of 2.8 was used. A good agreement between experimental and numerical results was found. The results indicated that the pressure distribution under the screw pile with a thick helix (non-deformed helix) and straight pile are similar when the helix is positioned (dh) at the pile tip (dh = 0). As the helix is moved further away from the pile tip (dh > 0), the pressure under the helix gradually decreases, while the pressure under the shaft increases and then decreases within a certain dh/Dh. The mobilized shear strength contribution of the helix decreased with the increase in helix position-to-helix diameter ratio (dh/Dh). Moreover, when dh/Dh ≥ 1.5, both central shaft and helix behaved independently, and their contribution in mobilized shear strength cannot be considered as a group. Regarding the effect of the helix position on the shaft pressure, when dh/Dh < 1.5, the ratio of screw pile to straight pile end-bearing capacity decreases almost linearly with the increase in dh/Dh. A modified equation is proposed that includes the two factors—helix position and shape (helix which differentiates screw pile shape from the straight pile)—to estimate the end-bearing capacity of the strong helix screw pile. [ABSTRACT FROM AUTHOR]

Frequent technology upgrades in telecommunications have led to an increase in wind load on the towers that hold this equipment. The legs of lattice towers are critical members to the structure's integrity as they transfer large portions of compressive load through to the foundations. Through the increasing amount of compressive load, these members could eventually fail due to insufficient strength, which has raised the need to reinforce existing structures. Currently within industry, retrofitting new members onto the existing legs is common, however there is currently little research that has been carried out to investigate the effectiveness of these methods. This research investigates the retrofit of a Circular Hollow Section (CHS) that has been strengthened with two steel rods and aims to provide greater clarity on the effectiveness of the design through numerical analysis. This was completed using ABAQUS 2021 by performing both linear and non‐linear buckling analysis. It has been found that the design can improve compressive strength by up to 277.3% for the short column which matches the predicted strength. For the long column, an increase of 130.2% was recorded which is significantly less then calculated values. The results obtained further stress the need for continued research in this field, with an emphasis on experimental results. [ABSTRACT FROM AUTHOR]

Chondrogenesis is the process of differentiation of stem cells into mature chondrocytes. Such a process consists of chemical, functional, and structural changes which are initiated and mediated by the host environment of the cells. To date, the mechanobiology of chondrogenesis has not been fully elucidated. Hence, experimental activity is focused on recreating specific environmental conditions for stimulating chondrogenesis and to look for a mechanistic interpretation of the mechanobiological response of cells in the cartilaginous tissues. There are a large number of studies on the topic that vary considerably in their experimental protocols used for providing environmental cues to cells for differentiation, making generalizable conclusions difficult to ascertain. The main objective of this contribution is to review the mechanobiological stimulation of stem cell chondrogenesis and methodological approaches utilized to date to promote chondrogenesis of stem cells in vitro. In vivo models will also be explored, but this area is currently limited. An overview of the experimental approaches used by different research groups may help the development of unified testing methods that could be used to overcome existing knowledge gaps, leading to an accelerated translation of experimental findings to clinical practice. [ABSTRACT FROM AUTHOR]

Numerous finite element methods have been widely used to predict the response of normal/high strength concrete columns confined with Fiber Reinforced Polymer (FRP) under different loading conditions. In this regard, simulating the response of FRP-confined reactive powder concrete (RPC) columns has been less emphasized. The present study aimed to propose a finite element model based on fiber finite element methodology in order to predict the behavior of FRP confined RPC columns under axial compressive load with different eccentricities. The columns were modeled with a nonlinear beam-column element with two nodes with distributed plasticity. In addition, the proposed finite element model in the present study indicated its simplicity, low computational efforts, and flexibility by adopting a perfect bond between RPC and FRP. Further, the obtained results from the finite element analysis were compared to those from available tested specimens. Based on the comparisons, the proposed model can provide highly satisfactory predictions. Finally, the proposed model can be useful for efficient applications in practical engineering projects.

This study investigates the load transfer mechanism that includes the effect of helix bending deflection on end-bearing capacity, distribution of ground pressure under the helix and soil deformation around the screw pile. The helix to shaft diameter ratio of 2.5 and 2.8 with a strong helix and a weak helix were used. The model ground was prepared with fine sand at 80% of relative density. To investigate the load transfer mechanism, the experimental tests were modelled in a 3D finite element code. A good agreement between the experimental and numerical approaches was found. The numerical analyses showed that large influence zone exists under screw pile with strong helix, which resulted in higher mobilized soil shear strength that contributed to higher end-bearing capacity. In the case of strong helix, uniform pattern of pressure distribution was observed under the central shaft and the helix. Similar pattern of pressure distribution under the central shaft was observed in weak helix case but the pattern of pressure distribution under the helix changed from uniform to triangular to trapezoidal at various stages during the load test. The normalized end-bearing capacity decreased linearly with the increase in normalized helix bending deflection in both approaches, i.e. experimental and numerical.

This experimental investigation reveals the projected benefits of concrete-filled double-skin tubular columns. These columns are made up of an outside steel tube, an interior UPVC pipe, and a sandwich of concrete among these tubes. The effect of the dimension ratio of the outer-to-inner tube, the thickness ratio of the outer tube, and the internal tube material (steel/UPVC) on the ultimate compressive strength of double-skin tubular columns samples filled with concrete are investigated. Finally, the experimental findings were compared to previously published design approaches in AISC (2010), GB50936 (2014), and EC4 (2004). The analysis revealed that GB50936 (2014) produces the best outcomes, followed by AISC (2010) and EC4 (2004). In addition, the samples were tested in elevated temperatures to study their post-fire axial capacity. It was discovered that the type of infilled concrete and interior tube material has no major impact on the performance of samples at elevated temperatures.

This work reports the investigations of the electric potential impacts on the mechanical buckling of the piezoelectric nanocomposite doubly curved shallow shells reinforced by functionally gradient graphene platelets (FGGPLs). A four-variable shear deformation shell theory is utilized to describe the components of displacement. The present nanocomposite shells are presumed to be rested on an elastic foundation and subject to electric potential and in-plane compressive loads. These shells are composed of several bonded layers. Each layer is composed of piezoelectric materials strengthened by uniformly distributed GPLs. The Halpin–Tsai model is employed to calculate the Young’s modulus of each layer, whereas Poisson’s ratio, mass density, and piezoelectric coefficients are evaluated based on the mixture rule. The graphene components are graded from one layer to another according to four different piecewise laws. The stability differential equations are deduced based on the principle of virtual work. To test the validity of this work, the current mechanical buckling load is analogized with that available in the literature. Several parametric investigations have been performed to demonstrate the effects of the shell geometry elastic foundation stiffness, GPL volume fraction, and external electric voltage on the mechanical buckling load of the GPLs/piezoelectric nanocomposite doubly curved shallow shells. It is found that the buckling load of GPLs/piezoelectric nanocomposite doubly curved shallow shells without elastic foundations is reduced by increasing the external electric voltage. Moreover, by increasing the elastic foundation stiffness, the shell strength is enhanced, leading to an increase in the critical buckling load.

Analysis of nonlinear response of thick FGM beams subjected to either thermal or mechanical load is performed. Beam is in contact with a three-parameter elastic foundation. Nonlinear component of the foundation may be of the hardening or softening type. Equilibrium equations of the clamped beam are obtained within the framework of von Karman assumptions and third-order shear deformation theory and solved using the two-step perturbation technique. It is shown that when the FGM beam is in contact with a sufficiently soft foundation, the post-buckling path of the heated/compressed FGM beam is unstable and therefore, the structure is imperfection sensitive. Communicated by Chandrika Prakash Vyasarayani [ABSTRACT FROM AUTHOR]

In this paper, a polynomial and trigonometric shape function are developed for the three-dimensional (3-D) stability analysis of a thick rectangular plate. This study has evaluated the effect of aspect ratio of the critical buckling load of a plate that is clamped on the first edge, free at the third edge, with the second and fourth edges simply supported respectively (CSFS) using a variational method. An expression of potential energy of thick plate was formulated using 3-D elastic principles thereafter, a compatibility equation of 3-D plate was derived through energy equation transformation to get the relations between the rotations and deflection. The solution of compatibility equations yields the exact plates shape function which is derived in terms of trigonometric and polynomial displacement and rotations. Similarly, by minimizing the energy equation with respect to the deflection, the direct governing equation was formulated. The solution of governing equation yields the deflection coefficient of the plate. By minimizing the potential energy equation with respect to deflection coefficient after the action deflection and rotations equation were substituted into it, a more realistic formula for calculation of the critical buckling load is established. The proposed method unlike the refined plate theory (RPT), considered all the six stress elements in the analysis. The result showed that the critical buckling loads from the present study using polynomial are slightly higher than those obtained using trigonometric theories signifying the more exactness of the latter. The result of the present study using the established 3-D model for both functions is satisfactory and closer to exact solution compared to the two-dimensional (2-D) RPT. The overall average percentage differences between the two functions recorded are 6.4%. This shows that at about 94% both approaches are the same and can be applied with confidence in the stability analysis of any type of plate with the boundary condition. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the response of calvarial and femoral osteoblasts cultured in a 3D hydrogel environment to cyclic compressive mechanical loading. Human foetal femoral and calvarial osteoblasts were encapsulated in a semi‐synthetic thiol‐modified hyaluronan gelatin polyethylene glycol diacrylate (PEGDA) cross‐linked HyStemC hydrogel. Constructs were subjected to a cyclic compressive strain of 33.4 kPa force every second for 5 s every hour for 6 h per day using FlexCell BioPress culture plates and compared to non‐compressed constructs. Cell viability, mineralisation, and morphological changes were observed over 21 days. BMP2, ALP, COL1A1, COL2A1, and OCN gene expression levels were quantified. Encapsulated osteoblast numbers increased and formed hydroxyapatite over a 21‐day period. Cell viability decreased under a cyclical strain when compared to cells under no strain. Femoral osteoblasts under strain expressed increased levels of BMP2 (53.9‐fold) and COL1A1 (5.1‐fold) mRNA compared to no strain constructs. Surprisingly, no BMP2 mRNA was detected in calvarial osteoblasts. Osteoblasts derived from endochondral (femoral) and intra‐membranous (calvarial) processes behaved differently in 3D‐constructs. We therefore recommend that site‐specific osteoblasts be used for future bone engineering and bone replacement materials and further research undertaken to elucidate how site‐specific osteoblasts respond to cyclic compressive loads. [ABSTRACT FROM AUTHOR]

Moment support interaction of multi‐span sandwich panels Self‐supporting double skin metal faced sandwich panels are usually designed and installed as multi‐span beams. In this case, there is always an interaction at the intermediate supports between the compressional normal force in the face sheet and the support reaction orthogonally to it, which can reduce the bending capacity. Many effects influencing the reduced load‐bearing capacity are not taken into account in current approval practice (and design). Within a research project funded by the DFG, experimental, numerical and analytical investigations were therefore carried out on sandwich panels. The main influences on the reduced wrinkling stress under an applied transverse compressive load were quantified and a possible solution was identified in order to take them into account in the future, e.g. within the scope of the approval tests. [ABSTRACT FROM AUTHOR]

Background: The aesthetics and strength of anterior porcelain layered zirconia (PLZ) crowns are mainly affected by the zirconia (Zr) coping design. There is a need for a modified design to enhance aesthetics with strength.Objectives: The purpose of this study was to compare the fracture resistance of anterior PLZ crowns having modified CAD-CAM Zr coping designs (in terms of thickness and marginal collar designs) with standard Zr copings.Methods: Fifty PLZ crowns were fabricated and divided into two groups: Gr 1: Standard Zr Coping (SZC) (control gr) with 0.5 mm thickness (Facial-F, Mesial-M, Distal-D, incisal-I, and Palatal-P) without a collar; Gr 2: Collar Zr Coping (CZC) (test gr) with 2.5 mm collar height on M, D, P and 0.2 mm F and variable facial wall thickness. Subgroups: Gr 2a: (CZC-0.5 mm) facial wall thickness 0.5 mm; Gr 2b: (CZC-0.4 mm) facial wall thickness 0.4 mm; Gr 2c: (CZC-0.3 mm) facial wall thickness 0.3 mm; Gr 2d: (CZC-0.2 mm) facial wall thickness 0.2 mm. The fracture load was determined and analysed using One-way ANOVA and Dunnet test.Results: The minimum fracture load was 927.36 ± 127.80 N observed for Gr 2c (CZC at 0.3 mm) while the maximum fracture load was 1373.61 ± 146.54 N observed for Gr 2a (CZC at 0.5 mm). A highly significant difference in mean fracture load among various Zr coping groups (p< 0.001) was determined.Conclusions: Novel Zr coping design for anterior PLZ crowns can provide better aesthetics with strength. Reducing the thickness of Zr coping in the aesthetic zone to 0.2 mm and providing a modified collar design (2.5 mm collar height on M, D, P, and 0.2 mm F) would provide strength without jeopardizing aesthetics. [ABSTRACT FROM AUTHOR]

Unstiffened and stiffened cylindrically curved plates are often used in ship structures. For example, they can be found on a deck with a camber, a side shell at the fore and aft parts, and the circular bilge part of a ship structure. It is believed that such cylindrically curved plates can be fundamentally modelled using a portion of a circular cylinder. From estimations using cylindrically curved plate models, it is known that the curvature generally increases the buckling strength compared to a flat plate under axial compression. The existence of curvature is also expected to increase both the ultimate and buckling strengths. In the present study, a series of finite element analyses were conducted on stiffened curved plates with several varying parameters such as the curvature, panel slenderness ratio, and web height and type of stiffener applied. The results of numerical calculations on stiffened and unstiffened curved plates were examined to clarify the influences of such parameters on the characteristics of their buckling/plastic collapse behavior and strength under an axial compression.

Many factors contribute to the development and progression of intervertebral disc (IVD) degeneration. This study was designed to assess the effects of compressive load magnitude on IVD metabolism. It was hypothesized that as load magnitude increased, there would be a significant increase in release of proinflammatory and degradative biomarkers, and a significant decrease in tissue proteoglycan (GAG) and collagen contents compared with unloaded controls. IVD whole organ functional spinal units (FSU) consisting of cranial and caudal body halves, cartilage endplates, and IVD (n = 36) were harvested from the tails of six Sprague Dawley rats, and FSUs were cultured at 0.0 MPa, 0.5 MPa, or 1.0 MPa at 0.5 Hz for 3 days. After culture, media were collected for biomarker analysis and FSUs were analyzed for extracellular matrix composition. Significant differences were determined using a one‐way analysis of variance or Kruskal–Wallis test and post hoc analyses. Media concentrations of IFN‐γ, IL‐6, IL‐1β, and MMP‐8 were significantly higher in the 0.5 MPa compared with the 0.0 MPa group. Media concentrations of PGE2 and TIMP‐1 were significantly higher in the 1.0 MPa group compared with the 0.0 MPa group, and media PGE2 was significantly higher in the 1.0 MPa group compared with the 0.5 MPa group. Media GAG content was significantly higher in the 1.0 MPa group compared with the 0.0 MPa group, and percent GAG in the tissue was significantly lower in 0.5 MPa and 1.0 MPa groups compared with the 0.0 MPa group. Clinical Significance: These data suggest that there are magnitude‐dependent inflammatory and degradative IVD responses to cyclic loading, which may contribute to IVD degeneration. [ABSTRACT FROM AUTHOR]

This study investigates the load transfer mechanism that includes the effect of helix bending deflection on end-bearing capacity, distribution of ground pressure under the helix and soil deformation around the screw pile. The helix to shaft diameter ratio of 2.5 and 2.8 with a strong helix and a weak helix were used. The model ground was prepared with fine sand at 80% of relative density. To investigate the load transfer mechanism, the experimental tests were modelled in a 3D finite element code. A good agreement between the experimental and numerical approaches was found. The numerical analyses showed that large influence zone exists under screw pile with strong helix, which resulted in higher mobilized soil shear strength that contributed to higher end-bearing capacity. In the case of strong helix, uniform pattern of pressure distribution was observed under the central shaft and the helix. Similar pattern of pressure distribution under the central shaft was observed in weak helix case but the pattern of pressure distribution under the helix changed from uniform to triangular to trapezoidal at various stages during the load test. The normalized end-bearing capacity decreased linearly with the increase in normalized helix bending deflection in both approaches, i.e. experimental and numerical. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effect of the lateral meniscus (LM) complete radial tear at different tear sites on the load distribution and transmission functions. Methods: A compressive load of 300 N was applied to the intact porcine knees (n = 30) at 15°, 30°, 60°, 90°, and 120° of flexion. The LM complete radial tears were created at the middle portion (group M), the posterior portion (group P), or the posterior root (group R) (n = 10, each group), and the same loading procedure was followed. Finally, the recorded three-dimensional paths were reproduced on the LM-removed knees. The peak contact pressure (contact area) in the lateral compartment and the calculated in situ force of the LM under the principle of superposition were compared among the four groups (intact, group M, group P, and group R). Results: At all the flexion angles, the peak contact pressure (contact area) was significantly higher (lower) after creating the LM complete radial tear as compared to that in the intact state (p < 0.01). At 120° of flexion, group R represented the highest peak contact pressure (lowest contact area), followed by group P and group M (p < 0.05). The results of the in situ force carried by the LM were similar to those of the tibiofemoral contact mechanics. Conclusion: The detrimental effect of the LM complete radial tear on the load distribution and transmission functions was greatest in the posterior root tear, followed by the posterior portion tear and the middle portion tear in the deep-flexed position. Complete radial tars of the meniscus, especially at the posterior root, should be repaired to restore the biomechanical function. [ABSTRACT FROM AUTHOR]

Spruce and teak wood as anisotropic materials have complex behavior, particularly in the relationship between strain-rate and strength. High strain-rate compression tests between 590 s-1 and 3300 s-1 were carried out using two types of split Hopkinson pressure bar (SPHB) in order to measure the behavior of the wood along three principal axes with respect to fiber direction and growth rings. Numerical simulation using finite element software of the wood materials under high strain rates was performed and showed results with only a difference of 10% to the experimental results. The strain rate affects the strength of materials. In this case, it follows the power function, which means the higher the strain rate, the stronger the material. [ABSTRACT FROM AUTHOR]

This work reviews the ultimate compressive strength of aluminium plates and stiffened panels. The effect of boundary condition, initial imperfection, welding-induced residual stress and heat-affected zone are discussed. As the effect of manufacturing technology lacks in the literature, this effect is analysed employing the finite element method, considering the technology of welding and integrated extrusion. The numerical analyses have shown that the ultimate strength of the integrated extruded stiffened panel is relatively higher than the one of the traditional welded panel. [ABSTRACT FROM AUTHOR]

Background and aims: Iranian lifting guidelines are used as a risk assessment tool to prevent back pain in various industries. It is believed that the tools and methods used for the assessment should be simple and yet accurate.Given that this guideline adopted the American Conference of Governmental Hygienists (ACGIH) threshold limit values (TLVs) for lifting as allowable load limits and the accuracy of the allowable weight values has not been investigated. The objective of this study was to investigate the effect of trunk angle and anthropometric dimensions on the accuracy of the allowable weight limits. Methods: In this study, 15 workers who had experience in manual handling were asked to perform lifting tasks in accordance with the Iranian guidelines. The subjects’ anthropometric and trunk inclination angles were recorded using a triaxial accelerometer (inclinometer) for each task, and the compressive forces were estimated using 3DSSPP and then compared with NIOSH’s recommended limits (3400N). Results:The results showed that among 25 tasks, the mean trunk angle of 13 tasks was between 90 and 130 degrees. Statistically, considering a standard deviation above the determined mean, the average compressive forces estimated for 9 tasks were greater than NIOSH recommendation (3400). Conclusion: In most tasks, vertical height and horizontal distance of external loads from the body leads to awkward postures that can be the main reasons for increased compressive force. Lack adaption some anthropometric measurements result in increased mechanical loads on the back. Therefore, it seems that the limit values for Iranian lifting guideline are not sufficiently accurate to assess the risk of back injuries and needs to be reviewed.

This article is an experimental study of honeycomb core carbon skin sandwich composite panel using American Standards for Testing Materials, ASTM Standards C365/C365M-11a for honeycomb structure flatwise compressive strength. The objective of this article is to describe the process of validation done in the specimens prepared in the research are, to have consistency in terms of the strength and other mechanical properties and to ensure the materials prepared in the lab and can be applied for aviation application (aircraft control surface) later. The samples were prepared in accordance with aviation industry standards using the aviation industry materials at the approved facility (Malaysian Airlines Composite workshop in Subang). The experiment was conducted using the Instron 8802 UTM by following the ASTM Standards at the Faculty of Mechanical Engineering, University Teknologi MARA. From the experiment in accordance with the test standard, the results of the experiment showed the consistency in terms of strength of the specimen. The ultimate strength was found at the average 5.88 kN. [ABSTRACT FROM AUTHOR]

This paper presents a three-demensional micro-model for an unreinforced masonry (URM) column and masonry columns reinforced by FRP wrapping (RM). The column with dimensions of 0.3 x 0.3 x 1 m was constituted by twelve rows of solid burnt bricks bonded by mortar joints. The RM column was wrapped in four external FRP sheets. A heterogeneous model, in which masonry units, mortar joints and reinforcement are materially and geometrically accurately described, was chosen. Both bricks and mortar are modelled with independent behavior in compression and tension. The FRP reinforcement is assumed to behave linear-elastically. The reinforcement was modelled under the assumption of perfect adhesion between the elastic FRP strips and the damageable masonry support. Numerical results are compared with experimental ones in order to confirm conclusions about the behavior of URM and RM columns under concentric compressive load determined based on the experimental part of the research program. The comparison between experimental and numerical findings shows good agreement and the adopted numerical model is suitable to predict the ultimate load and allows a better understanding of the behavior of brick masonry columns under concentric compression before and after reaching the ultimate load. For all simulations, the commercial software package ABAQUS was used. [ABSTRACT FROM AUTHOR]

In recent years, carbon fiber reinforced polymer (CFRP) strengthening of steel members has attracted the attention of many researchers. To the author's knowledge, no research on the behavior of deficient square hollow sections steel members strengthened using CFRP under combined compressive load and torsional moment has been presented. However, this study explored the effect of the use of CFRP strengthening on the behaviors of these steel members. The results indicated that application of CFRP sheets for strengthening the deficient hollow steel members under combined compressive load and torsional moment could recover the strength lost due to deficiency, significantly. [ABSTRACT FROM AUTHOR]

In this research, the multilayered composite plates made of glass/epoxy material were experimentally and numerically investigated under compressive loading conditions. The intact and defected structures were analyzed with the use of finite element method. The influence of the thickness and geometrical imperfection level were carried out in the linear buckling analysis. The nonlinear analysis was performed to determine the influence of the delamination length on the buckling behavior of the plate. The numerical results were validated by experiments. Experimental tests were performed for structures having artificial delamination between laminate layers. The buckling behavior was monitored using the nondestructive and noncontact structural vision-based health monitoring system (the digital image correlation (DIC)). The influence of the different delamination behavior during the tests on the compressive load capacity was determined by a detailed analysis of DIC measurements. The 20% reduction of the compressive load was noticed in the cases with local buckling of delamination. [ABSTRACT FROM AUTHOR]

In this study, the influence of scan strategies, such as scan order and scan patterns, on compressive load capacity was investigated for the aluminum alloy AlSi12-made lattice structures fabricated by selective laser melting. The scan order of concentric scan patterns affected compressive load capacity. Better mechanical properties were obtained when the scan order was set from the outside. Setting the scan order from the inside caused coarsening of the grains at the center of the strut, thus worsening the mechanical properties due to the reduced area fraction of the finegrained regions. The mechanism of such grain coarsening was explained based on the heat transfer direction. Furthermore, the scan pattern also affected the size and orientation of the grains in the lower zone of the strut as well as its geometrical accuracy. A stripe pattern with a rotation of 67° from layer to layer decreased the geometrical accuracy but increased the hardness of the strut owing to the smaller size and random orientation of the grains in the lower strut zone. [ABSTRACT FROM AUTHOR]