Search

Background: While measuring meniscal extrusion quantitatively is an early risk factor for knee osteoarthritis (KOA), the biomechanics involved in this process are not well understood. This study aimed to investigate the effects of varying degrees of medial and lateral meniscal extrusion and their material softening on knee osteoarthritis progression. Methods: Finite element analysis (FEA) was utilized to simulate varying degrees of meniscal extrusion (1–5 mm) in 72 knee joint models, representing progressive meniscal degeneration and material softening due to injury. Changes in von Mises stress of the cartilage and menisci and the load distribution on the tibial plateau's meniscus and cartilage were studied under balanced standing posture in both healthy and injured knees, and statistical analysis was performed using Spearman correlation. Results: Compared to healthy knees, peak stress in medial compartment tissues increased by over 40% with 4 mm of medial meniscus extrusion, and in lateral compartment tissues with 2 mm of lateral meniscus extrusion. Meniscus extrusion reduced the contact load between the meniscus and femoral cartilage but increased it between the tibial and femoral cartilages, with a maximum increase up to fivefold. Spearman correlation analysis indicated that meniscal extrusion significantly affected peak stress and contact loads in the respective knee compartment (p < 0.001), with a lesser impact on the opposite compartment. Notably, medial meniscal extrusion also significantly increased peak stress in the lateral tibial cartilage (p < 0.05). Conclusions: The quantitative analysis revealed that meniscal extrusion significantly affected the biomechanics of soft tissues within the same compartment, with limited impact on the opposite side. Specifically, Medial extrusion beyond 4 mm significantly affected the biomechanics of the medial compartment, while lateral extrusion over 2 mm had a similar impact on the lateral compartment. Meniscal softening, without altering joint contact characteristics, primarily affected the biomechanics of the meniscus itself, with minimal impact on other soft tissues. [ABSTRACT FROM AUTHOR]

Purpose: This paper presents the approximate limit pressure solution for shape-imperfect and through-wall circumferential cracked (TWCC) 90° pipe bends at the intrados region. Finite element (FE) limit analysis was used to estimate the limit pressure by considering the small geometrical change effects. Design/methodology/approach: Three-dimensional (3D) geometric linear FE methodology was implemented to investigate the limit pressure of structurally deformed TWCC 90° pipe bends. The material considered in the analysis is elastic perfectly plastic (EPP). The limit pressure of TWCC shape-distorted pipe bends was predicted from the corresponding internal pressure when von-Mises stress was equal to or just exceeded the material's yield strength for all the models. The theoretical solution which was published in the literature was used to evaluate the current FE approach. Findings: Ovality Co and TWCC at the intrados region caused a considerable impact on pipe bends, while the thinning? Ct produced a negligible effect and hence was not included in the analysis. With the combined effect, the bend portion of pipe bend experiences substantial influence, and the TWCC effect consequently increases with 45o, 60o and 90o crack angles and decreases the limit pressure of pipe bends. An improved closed-form empirical limit pressure solution was proposed for TWCC shape-distorted pipe bends at the intrados region. Originality/value: In the limit pressure analysis of 90° pipe bends, the implications of structural irregularities (ovality and thinning) and TWCC have not been examined and reported. [ABSTRACT FROM AUTHOR]

Abstract Background While measuring meniscal extrusion quantitatively is an early risk factor for knee osteoarthritis (KOA), the biomechanics involved in this process are not well understood. This study aimed to investigate the effects of varying degrees of medial and lateral meniscal extrusion and their material softening on knee osteoarthritis progression. Methods Finite element analysis (FEA) was utilized to simulate varying degrees of meniscal extrusion (1–5 mm) in 72 knee joint models, representing progressive meniscal degeneration and material softening due to injury. Changes in von Mises stress of the cartilage and menisci and the load distribution on the tibial plateau’s meniscus and cartilage were studied under balanced standing posture in both healthy and injured knees, and statistical analysis was performed using Spearman correlation. Results Compared to healthy knees, peak stress in medial compartment tissues increased by over 40% with 4 mm of medial meniscus extrusion, and in lateral compartment tissues with 2 mm of lateral meniscus extrusion. Meniscus extrusion reduced the contact load between the meniscus and femoral cartilage but increased it between the tibial and femoral cartilages, with a maximum increase up to fivefold. Spearman correlation analysis indicated that meniscal extrusion significantly affected peak stress and contact loads in the respective knee compartment (p

Polymers can be natural or synthetic and are largely used in several applications due to their versatile properties. Polymers can vary widely in their properties and applications, and they are a fundamental part of our everyday life. Polypropylene (PP) is a thermoplastic polymer from the polyolefin family. It is among the most widely used plastics in various automotive and packaging industries. Although PP is widely used in commodity range, still its applications are restricted in niche areas due to lack of toughness which can be improved by incorporation of rubbery materials or fillers. Graphene (G) is one of the nanomaterials used to strengthen polypropylene. Graphene is recognized for its outstanding thermo-mechanical properties, making it a highly desirable material in various fields of science and technology. Benefits gained by incorporation of graphene nanoparticles into polypropylene are studied by researchers. In this study, a finite element analysis is performed which shows the mechanical behaviour of PP and G using ANSYS, which is one of the most powerful finite element analysis (FEA) softwares that can help to perform such simulations to understand stress, strain, deformation of components before actual experimentation. The bending load of 100 N and 1400 N in vertical z-direction are applied for 100% PP model, 100% G model and 50% PP+50% G model and the linear part of stress-strain curve is captured in this analysis.

The performance of O-rings is crucial to the large variety of core equipment or components that employ O-ring seals. O-ring surface imperfections that meet quality standards are allowed to be put into service. However, the presence of surface imperfections will inevitably affect the performance of the O-ring seal. To this end, in this study, nonlinear finite element models of O-ring structures with an ideal circular cross section and three surface imperfections of parting line projection, backrind, and excessive trimming in accordance with ISO standards are developed. On this basis, their contact conditions and stress distributions are calculated, analyzed, discussed, and compared. The results show that the maximum contact pressure in the area where the imperfection is located increases and that the presence of the imperfection does not reduce the sealing performance. Backrind under low pressure conditions and excessive trimming do not affect the maximum Von-Mises stress. While backrind under high pressure conditions and parting line projection can make the maximum Von-Mises stress increase significantly. In particular, at a fluid pressure of 10 MPa, backrind causes a 21% increase in the maximum Von-Mises stress, while parting line projection causes a 198% increase. Such a large increase in stress will increase the likelihood of fatigue failure and breakage. [ABSTRACT FROM AUTHOR]

Polymers can be natural or synthetic and are largely used in several applications due to their versatile properties. Polymers can vary widely in their properties and applications, and they are a fundamental part of our everyday life. Polypropylene (PP) is a thermoplastic polymer from the polyolefin family. It is among the most widely used plastics in various automotive and packaging industries. Although PP is widely used in commodity range, still its applications are restricted in niche areas due to lack of toughness which can be improved by incorporation of rubbery materials or fillers. Graphene (G) is one of the nanomaterials used to strengthen polypropylene. Graphene is recognized for its outstanding thermo-mechanical properties, making it a highly desirable material in various fields of science and technology. Benefits gained by incorporation of graphene nanoparticles into polypropylene are studied by researchers. In this study, a finite element analysis is performed which shows the mechanical behaviour of PP and G using ANSYS, which is one of the most powerful finite element analysis (FEA) softwares that can help to perform such simulations to understand stress, strain, deformation of components before actual experimentation. The bending load of 100 N and 1400 N in vertical z-direction are applied for 100% PP model, 100% G model and 50% PP+50% G model and the linear part of stress-strain curve is captured in this analysis. [ABSTRACT FROM AUTHOR]

This paper presents the research results on the strength of materials and power of the Toyota 3C engine when changing the structure and number of blades of the compressor wheel in the turbocharger. 3D models of different compressor wheels were created using reverse engineering and then simulated in the ANSYS environment with turbine shaft rotation speeds of 10,000, 15,000, and 20,000 rpm, respectively, to examine the strength of the compression wheel materials. To evaluate engine power, compressor wheels were machined on a 5-axis CNC milling machine. The MP 100S specialized test bed was used to perform experiments and compare engine power when using the original and alternative compressor wheels of the CT9 turbocharger. The compressor wheels were made of aluminum alloy, with a structure and number of blades selected to ensure durability when working. The CT9 turbocharger has a four-pair blade compressor wheel that consistently delivers higher engine power than in other cases. [ABSTRACT FROM AUTHOR]

In this study, we computationally examine the biomechanics of a cerebral aneurysm (CA) using a two-way Fluid-Structure Interaction (FSI) approach. The integrated approach using computational fluid dynamics (CFD) and computational solid dynamics (CSD) aims to connect the intra-aneurysmal environment and the rupture process and assess the risk of aneurysm rupture. The velocity distribution and the wall shear stress (WSS) were calculated within these aneurysms. The dynamic response of cerebral aneurysms was predicted using CSD. We conducted parametric analyses based on CA aspect ratio (AR) and viscosity sensitivity analysis to allow easier exploration of their effects. The findings demonstrate that velocity values decrease as aneurysm size increases, associated with the drop in WSS. Results demonstrated how the wall deformation associated with the growth of CA aspect ratios causes strain and raises the danger of aneurysm rupture. [ABSTRACT FROM AUTHOR]

Pressure tanks play a pivotal role in various industrial applications, serving as vessels for the storage of gases under different pressures and environmental conditions. The burgeoning interest in hydrogen gas as a clean energy source has necessitated a comprehensive assessment of pressure tank structural integrity, particularly under high-pressure demands exceeding 700 bar. In this study, we systematically investigate the influence of different aluminum alloys, including AL6061, AL7075, and AL7178, reinforced with various fiber/epoxy composite materials. Our primary objective is to identify the optimal combination of liner and composite materials, along with the number of composite layers and fiber winding orientations that minimize distortion energy within the tank's liner and composite layers while maximizing safety factors. Our results indicate that distortion energy decreases as the fiber angle increases from zero to 75°, with the ideal fiber orientation angle shifting with the number of composite layers. The lowest distortion energy levels in the liner were achieved in composite tanks comprising 60 laminates of reinforcing composite material, wound at an orientation angle of [±55°/90°]. Across various internal pressure levels, pressure tanks reinforced with boron/epoxy composite material consistently outperformed other fiber materials. In terms of aluminum liner materials, AL6061 exhibited a remarkable 10.5% reduction in distortion energy on average when compared to AL7075. Safety indices revealed that pressure tanks reinforced with aramid/epoxy composite material provided the highest level of reliability, particularly when applying the maximum principal stress criterion. Carbon/epoxy and graphite/epoxy composites followed closely. In contrast, glass/epoxy and Kevlar/epoxy composites did not meet the stringent safety requirements for high-pressure storage tanks. These findings offer invaluable guidance for designing high-pressure composite tanks, ensuring their structural integrity and safety when storing hydrogen gas at elevated pressures, and exemplify the importance of materials and design considerations for such critical applications. [ABSTRACT FROM AUTHOR]

Abstract Background The rolling contact joint (RCJ) mechanism is a system of constraint that allows two circular bodies connected with flexible straps to roll relative to one another without slipping. This study aims to compare the biomechanical characteristics between the conventional proximal interphalangeal joint (PIPJ) flexible hinge (FH) implant and the novel PIPJ implant adopting a RCJ mechanism during PIPJ range of motion using finite element (FE) analysis. Methods The three-dimensional (3D) surface shape of a conventional PIPJ FH implant was obtained using a 3D laser surface scanning system. The configuration and parameters of the novel PIPJ implant were adapted from a previous study. The two implants were assumed to have the same material characteristics and each implant was composed of a hyperelastic material, silicone elastomers. The configuration data for both implants were imported to a computer-aided design program to generate 3D geometrical surface and hyperelastic models of both implants. The hyperelastic models of both implants were imported into a structural engineering software to produce the FE mesh and to perform FE analysis. The FE analysis modeled the changes of mechanics during flexion–extension motion between 0° and 90° of two PIPJ implants. The mean and maximum values of von-Mises stress and strain as well as the total moment reaction based on the range of motion of the PIPJs were calculated. The mean values within the PIPJ’s functional range of motion of the mean and maxinum von-Mises stress and strain and the total moment reaction were also determined. Results The maximum values for the von-Mises stress, and strain, as well as the total moment reactions of the conventional PIPJ FH and novel PIPJ implants were all at 90° of PIPJ flexion. The maximum value of each biomechanical property for the novel PIPJ implant was considerably lower compared with that of the conventional PIPJ FH implant. The mean values within the PIPJ’s functional range of motion of the maximum von-Mises stress and strain for the novel PIPJ implant was approximately 6.43- and 6.46-fold lower compared with that of the conventional PIPJ FH implant, respectively. The mean value within a PIPJ’s functional range of motion of the total moment reaction of the novel PIPJ implant was approximately 49.6-fold lower compared with that of the conventional PIPJ FH implant. Conclusions The novel PIPJ implant with an RCJ mechanism may offer improved biomechanical performance compared with conventional PIPJ FH implant.

Over the past few decades, there has been a growing popularity in utilizing finite element analysis to study the spine. However, most current studies tend to use one specimen for their models. This research aimed to validate multiple finite element models by comparing them with data from in vivo experiments and other existing finite element studies. Additionally, this study sought to analyze the data based on the gender and age of the specimens. For this study, eight lumbar spine (L2–L5) finite element models were developed. These models were then subjected to finite element analysis to simulate the six fundamental motions. CT scans were obtained from a total of eight individuals, four males and four females, ranging in age from forty-four (44) to seventy-three (73) years old. The CT scans were preprocessed and used to construct finite element models that accurately emulated the motions of flexion, extension, lateral bending, and axial rotation. Preloads and moments were applied to the models to replicate physiological loading conditions. This study focused on analyzing various parameters such as vertebral rotation, facet forces, and intradiscal pressure in all loading directions. The obtained data were then compared with the results of other finite element analyses and in vivo experimental measurements found in the existing literature to ensure their validity. This study successfully validated the intervertebral rotation, intradiscal pressure, and facet force results by comparing them with previous research findings. Notably, this study concluded that gender did not have a significant impact on the results. However, the results did highlight the importance of age as a critical variable when modeling the lumbar spine. [ABSTRACT FROM AUTHOR]

Segmental arterial mediolysis (SAM) is an asymptomatic, non-atherosclerotic and noninflammatory disease of unknown etiology. It affects medium-sized arteries and is characterized by vacuolization and lysis at the level of the media which can lead to dissection, steno-occlusion, or an aneurysm. In this article, a simulation of fluid-structure interaction in an artery altered by segmental mediolysis was reported. The study showed that the reduction in elasticity of the media layer of the artery due to the deterioration of collagen has little influence on the velocity field, the pressure field as well as on the deformations of the artery, thus conferring a silent and asymptomatic character to the pathology. The Von-Mises stress is very high at the level of the intima which can lead to arterial dissection with the appearance of a false channel. An increase in the Von-Mises stress of around 375 % was predicted by the COMSOL code. The combined effect of mediolysis and the increase in blood pressure causes increases in the Von-Mises stress at the level of the intima and the adventitia which are respectively 6.10 and 4.62 times greater than those of the healthy artery, which demonstrates that hypertension could be a determining factor in triggering arterial dissection. [ABSTRACT FROM AUTHOR]

Background: The rolling contact joint (RCJ) mechanism is a system of constraint that allows two circular bodies connected with flexible straps to roll relative to one another without slipping. This study aims to compare the biomechanical characteristics between the conventional proximal interphalangeal joint (PIPJ) flexible hinge (FH) implant and the novel PIPJ implant adopting a RCJ mechanism during PIPJ range of motion using finite element (FE) analysis. Methods: The three-dimensional (3D) surface shape of a conventional PIPJ FH implant was obtained using a 3D laser surface scanning system. The configuration and parameters of the novel PIPJ implant were adapted from a previous study. The two implants were assumed to have the same material characteristics and each implant was composed of a hyperelastic material, silicone elastomers. The configuration data for both implants were imported to a computer-aided design program to generate 3D geometrical surface and hyperelastic models of both implants. The hyperelastic models of both implants were imported into a structural engineering software to produce the FE mesh and to perform FE analysis. The FE analysis modeled the changes of mechanics during flexion–extension motion between 0° and 90° of two PIPJ implants. The mean and maximum values of von-Mises stress and strain as well as the total moment reaction based on the range of motion of the PIPJs were calculated. The mean values within the PIPJ's functional range of motion of the mean and maxinum von-Mises stress and strain and the total moment reaction were also determined. Results: The maximum values for the von-Mises stress, and strain, as well as the total moment reactions of the conventional PIPJ FH and novel PIPJ implants were all at 90° of PIPJ flexion. The maximum value of each biomechanical property for the novel PIPJ implant was considerably lower compared with that of the conventional PIPJ FH implant. The mean values within the PIPJ's functional range of motion of the maximum von-Mises stress and strain for the novel PIPJ implant was approximately 6.43- and 6.46-fold lower compared with that of the conventional PIPJ FH implant, respectively. The mean value within a PIPJ's functional range of motion of the total moment reaction of the novel PIPJ implant was approximately 49.6-fold lower compared with that of the conventional PIPJ FH implant. Conclusions: The novel PIPJ implant with an RCJ mechanism may offer improved biomechanical performance compared with conventional PIPJ FH implant. [ABSTRACT FROM AUTHOR]

The finite element method (FEM) is widely recognized as a powerful numerical analysis technique for approximating solutions in structural mechanics. Addressing the configuration of plate-type structures, particularly those with discontinuities, is crucial not only in ship and aircraft construction but also in various other fields. Structural discontinuities occur when there are sudden changes in the cross-section of structural members due to material imperfections or high-stress areas. This paper focuses on the fundamental principles of FEM for solving two-dimensional plane stress problems and analyzing stresses such as normal stress, shear stress, and von-Mises stress at the four integration points (Gauss points) in different sections of ship structures, particularly in vulnerable regions. To address structural discontinuity problems in various ship structures, a finite element program utilizing object-oriented techniques was developed, employing four-node quadrilateral elements. The analysis results of gauss point stresses obtained from the developed program were validated against a commercial finite element analysis software to ensure accuracy and reliability. Additionally, a mesh viewing program has been developed in the Python programming language to enable the visualization and analysis of the generated mesh using the developed object-oriented finite element program. [ABSTRACT FROM AUTHOR]

Velg cast wheel sering mengalami kerusakan yang menyebabkan rusaknya pada bagian bibir velg atau pecahnya spoke jika menopang beban berlebih. Aspek keselamatan sangat penting diperhatikan dalam industri otomotif karena menyangkut nyawa penumpang. Optimalisasi struktural berbagai komponen kendaraan telah menunjukkan bahwa kinerja kendaraan sangat dipengaruhi oleh berat komponen. Berdasarkan permasalahan tersebut maka tujuan dibuatnya penelitian ini untuk merancang model desain velg cast wheel yang ringan namun mampu menahan beban sebesar 503 N. Sehingga perlu dibuat analisis menggunakan perbandingan model desain dan variasi material, serta dilakukan simulasi statis menggunakan software Solidworks 2018. Hasil yang dicari adalah von mises, displacement, strain, factor of safety, dan menghasilkan desain yang ringan. Hasil simulasi pada ketiga model masih aman dalam menahan beban 503 N, karena nilai factor of safety tidak kurang dari 1. Untuk massa desain dengan variasi material, mendapatkan hasil yang lebih ringan dari velg aslinya.

Permanent tooth avulsion is a common but extremely serious dental injury that can negatively affect both economic output and lifestyle. Even though it is not a disease, no one is ever completely safe from the possibility of suffering from these disastrous injuries. Dental implants play a vital role in the treatment of such injuries (tooth loss). This work was focused on to find the effects of two different platform switched abutment-implant assembly on hard tissues (Cortical and cancellous) bone. Materialized Mimics Medical Software was used for processing clinical imaging (CBCT) data of mandibular bone and micro-CT data of implant (5.5 × 9.5 mm), Abutments (Pt. sw. I and Pt. sw. II) and final 3D model of all parts were obtained by Fusion 360 CAD software and implanted into a right mandible bone block. Implant-Abutment with different switching assembly as platform switched-I (Pt. Sw. I) Ø5.5-mm implant and Ø3.8-mm abutment and the platform switched-II (Pt. Sw. II) Ø5.5-mm implant and Ø4.5-mm abutment were compared. Each model was subjected to 50 N, 100 N and 150 N longitudinal and lateral loads at occlusal surface of the abutment to evaluate the mechanical parameters. ANSYS 2020R1 was used to conduct the computational analysis. Mechanical characteristics such as von-Mises stresses and total deformation were measured in the hard tissues using finite element modelling. Under the application of different loads the cancellous bone experiences maximum von misses stress 4.7 MPa and 5.4 MPa for Pt. Sw. I and Pt. Sw. II respectively under longitudinal load and 7.4 MPa and 8.7 MPa for Pt. Sw. I and Pt. Sw. II respectively under lateral load. Similar trends were observed for cortical bone. While maximum total deformation of 2.1 µm (Pt. Sw. I) and 2.2 µm (Pt. Sw. II) under longitudinal load and 4.4 µm and 4.6 µm in cancellous bone and cortical bone under longitudinal load and 4.4 µm (Pt. Sw. I) and 4.6 µm (Pt. Sw. II) under lateral load in cancellous and 7.5 µm (Pt. Sw. I) and 8 µm (Pt. Sw. II) in cortical bone were recorded. The analysis may help to prevent the progression of marginal bone loss (MBL) because lower results for these variables indicated for higher platform switching in marginal bone. The findings of computational frameworks can help clinicians and other medical professionals make more informed decisions when selecting a treatment strategy from the many options available.

Present study considered deformation of a solid plate as result of external pressure wave. So, a detailed investigation of underwater explosions (UNDEX) and their effects on solid structures is the main objective of this paper. To accomplish this, numerical methods have been used to analyze the UNDEX structure qualitatively and quantitatively. Afterward, perpendicular blades are used to reinforce a marine structure. Governing equations in solid and fluid media were discretized using finite element and finite volume schemes, respectively. As for fluid-structure interaction (FSI), two-way coupling methods were used to map the results of fluid and solid media. The numerical method's validity can be confirmed by comparing numerical results with the analytical solution. Pressuretime diagrams follow the analytical solution reasonably well, indicating that the numerical method is valid. Additionally, results indicate that a pressure wave with amplitude of 20 MPa is generated by the detonation of explosive charge under water. Furthermore, reinforcement blades appear to reduce deformation in structures by increasing their resistance to explosive charges. These blades increase the strength of the plate where it could tolerate the Von-Mises stress up to 750 MPa. [ABSTRACT FROM AUTHOR]

This paper examines the impact of temperature, pressure, and blade thickness on the stresses experienced by impeller blades during operation. The impeller is subject to a range of stresses arising from thermal, fluid, and mechanical factors that can cause deformation if they exceed certain thresholds. The study focuses on an impeller supplied by HAUS Centrifuge Technologies, which suffered damage while operating at 33000 rpm. Six blade thickness offsets, ranging from 0.05 mm to 0.15 mm, were analyzed structurally, and the Von-Mises stresses were compared to the impeller material yield strength. The impeller with the lowest stress, at 197.43 MPa, was chosen for fluid-structure interaction analysis. The impeller was then manufactured and tested for performance using ISO 5389 standard in HAUS test facility. The CFD results indicated that the polytropic efficiency of the thickened impeller increased to 86.57%, compared to the original impeller polytropic efficiency of 75.8%. However, the volumetric flow decreased from 4211.3 m³ per hour to 3658.3 m³ per hour when using “the thicker impeller”. The data collected supports the conclusion that an increase in blade thickness can help to reduce the stresses acting on the blade. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the impact of posterior element and ligament removal on the maximum von Mises stress, and maximum shear stress of the eight-layer annulus for treating stenosis at the L3-L4 and L4-L5 levels in the lumbar spine. Previous studies have indicated that laminectomy alone can result in segmental instability unless fusion is performed. However, no direct correlations have been established regarding the impact of posterior and ligament removal. To address this gap, four models were developed: Model 1 represented the intact L2-L5 model, while model 2 involved a unilateral laminotomy involving the removal of a section of the L4 inferior lamina and 50% of the ligament flavum between L4 and L5. Model 3 consisted of a complete laminectomy, which included the removal of the spinous process and lamina of L4, as well as the relevant connecting ligaments between L3-L4 and L4-L5 (ligament flavum, interspinous ligament, supraspinous ligament). In the fourth model, a complete laminectomy with 50% facetectomy was conducted. This involved the same removals as in model 3, along with a 50% removal of the inferior/superior facets of L4 and a 50% removal of the facet capsular ligaments between L3-L4 and L4-L5. The results indicated a significant change in the range of motion (ROM) at the L3-L4 and L4-L5 levels during flexion and torque situations, but no significant change during extension and bending simulation. The ROM increased by 10% from model 1 and 2 to model 3, and by 20% to model 4 during flexion simulation. The maximum shear stress and maximum von-Mises stress of the annulus and nucleus at the L3-L4 levels exhibited the greatest increase during flexion. In all eight layers of the annulus, there was an observed increase in both the maximum shear stress and maximum von-Mises stress from model 1&2 to model 3 and model 4, with the highest rate of increase noted in layers 7&8. These findings suggest that graded posterior element and ligament removal have a notable impact on stress distribution and range of motion in the lumbar spine, particularly during flexion.

This paper presents a new investigation of the recirculation channel combined with bleeding channels, where the recirculation airflow recirculates air from downstream high-pressure region to an upstream through a recirculation channel located on shroud surface in rotor domain and the bleeding airflow through 36 bleeding channels sited on the recirculation channels ejects airflow to the by-pass channel in a single-stage transonic axial compressor used in turbofan engine. The object of this investigation is to reduce the vortex flow in the tip leakage region by finding the effects of recirculation and bleeding channels design on aeromechanic performance of a single-stage axial compressor, NASA Stage 37. A parametric study of the recirculation and bleeding channels were performed using various geometric parameters related to the locations and shapes of the recirculation and bleeding channels to find the effects of recirculation and bleeding channels design on aeromechanic performance, such as pressure ratio, efficiency, stall margin, blade tip deformation and Von-Mises stress. The numerical results showed an increase in aerodynamic performance and decrease in blade tip deformation with recirculation-bleeding channels, compared to the smooth casing. [ABSTRACT FROM AUTHOR]

This study aims to introduce an efficient method for calculating the response amplitude operator (RAO) of combined stresses in frequency domain hydroelastic analysis. After performing frequency domain hydroelastic analysis, the stress components are calculated as a harmonic response. However, combined stresses, derived from stress components in various orientations, notably von-Mises stress and principal stress, are not harmonic functions. The combined stresses have been often used for fatigue strength analysis of structures. Since the combined stresses are not harmonics, it is not an easy task to calculate the RAO (maximum response) of the combined stresses for a given input wave period. This paper proposes a method to directly compute the maximum response, or RAO, of these combined stresses, aiming to offer a technique that can be easily applied to the design of ships and floating structures. Among various combined stresses, we focus on the RAO calculation of the von-Mises stress and principal stress, which are the most commonly used in engineering practice. Compared to the existing RAO calculation method, the proposed method provides more accurate results with less computation time. We demonstrate the validity and advantages of the proposed method through various numerical examples. • We propose a direct calculation procedure for stress RAO in hydroelastic analysis. • The stress components are directly substituted into the coupled stress equation. • Utilizing the properties of trigonometric functions, the maximum value is then found. • The effectiveness of the proposed procedure is presented through numerical examples. [ABSTRACT FROM AUTHOR]

The escalating use of plastic products alongside rising ambient temperatures has intensified concerns regarding their performance under diverse thermal conditions. This paper delves into the intricate relationship between plastic materials, ambient temperature fluctuations, and resulting stresses. Various grades of plastic materials are subjected to distinct ambient temperatures to elucidate stress generation—a pivotal aspect in plastic product design. Leveraging the finite element method, a comprehensive analysis is conducted to design and assess a plastic product under specified loads and ambient temperatures. The study encompasses the evaluation of equivalent stresses, normal and shear stresses, and deformations. Ultimately, the research culminates in the development and analysis of a thermally stable plastic product, offering valuable insights for robust design practices amidst evolving environmental conditions.

Over the past few decades, there has been a growing popularity in utilizing finite element analysis to study the spine. However, most current studies tend to use one specimen for their models. This research aimed to validate multiple finite element models by comparing them with data from in vivo experiments and other existing finite element studies. Additionally, this study sought to analyze the data based on the gender and age of the specimens. For this study, eight lumbar spine (L2–L5) finite element models were developed. These models were then subjected to finite element analysis to simulate the six fundamental motions. CT scans were obtained from a total of eight individuals, four males and four females, ranging in age from forty-four (44) to seventy-three (73) years old. The CT scans were preprocessed and used to construct finite element models that accurately emulated the motions of flexion, extension, lateral bending, and axial rotation. Preloads and moments were applied to the models to replicate physiological loading conditions. This study focused on analyzing various parameters such as vertebral rotation, facet forces, and intradiscal pressure in all loading directions. The obtained data were then compared with the results of other finite element analyses and in vivo experimental measurements found in the existing literature to ensure their validity. This study successfully validated the intervertebral rotation, intradiscal pressure, and facet force results by comparing them with previous research findings. Notably, this study concluded that gender did not have a significant impact on the results. However, the results did highlight the importance of age as a critical variable when modeling the lumbar spine.

Background: Porous materials are recommended for orthopedic applications as they eliminate issues of interfacial instability with tissues and reduce mechanical mismatch of the young’s modulus. Objective: The current research provides a finite element analysis (FEA) to investigate porous gyroid Ti6Al4V structure compared to a solid stem model for human tibial-knee implantation of total knee replacement (TKR).Material and Methods: In this study, the implant proximal portion was designed as porous gyroid Ti6Al4V structure with 500 µm pore size. CATIA V5R18 was used for modeling both gyroid and full solid models. Structural analysis was carried out using ANSYS R18.1 to evaluate the implant performance. Results: After gyroid implantation, the maximum von-Mises stress obtained under the tibial tray was increased to 10.081 MPa. Also, the maximum shear stress at the stem/bone interface was reduced to 0.7347 MPa. The stress concentration at the stem tip and the bone strain energy were also improved. The minimum factor of safety is 4.6 for the gyroid porous implant. A proof of concept model was additively manufactured successfully with pore size 577.7733 ± 34.762 µm. Conclusion: The results indicated enhanced clinical performance of the porous tibial-knee implant compared to the solid titanium implant via increasing the maximum von-Mises bone stresses and decreasing the maximum shear stress at the bone/implant interface.

Due to optimistic advancements in energy harvesting, there has been a consequential increase in MEMS energy harvesting systems. The enormous availability of low-frequency vibrations in the environment motivates researchers to convert them to usable electrical energy with reasonable efficiencies by implementing effective transduction procedures like piezoelectric, piezoresistive, capacitive, magnetic and thermomagnetic means. To reinforce this development, different structures of energy harvesters were modeled and simulated for its performance characteristics. In this research article, a piezoelectric ZnO nanowire-based energy harvesting system is considered and its usefulness was analysed for different performance metrics. The analysis results have shown that the modeled energy harvester does not succumb to fracture at low-frequency vibrations. The proposed nanowire energy harvester produced a power density of 1.45 W/m2 when subjected to low-frequency vibrations. Moreover, the maximum von-Mises stress observed was at 50 Hz which lies in the low-frequency vibration level thereby making a promising effect of scavenging maximum power. [ABSTRACT FROM AUTHOR]

The increased emphasis on vehicle and occupant safety in automotive accidents has necessitated research on vehicle crashworthiness during the design phase. The design of the bumper plays a significant role in mitigating pedestrian injuries and the risk of life during accidents. The present study is focused on the design and development of an economical external multilayered bumper that can be retrofitted to any car's existing bumper fascia while improving the safety of pedestrians without compromising the safety of engine components. The proposed multilayered bumper consists of spring and damper assembly along with a layer of high-density polyurethane foam. Finite element analysis has been performed to compute the total deformation, equivalent Von-Misses stress, spring–damping coefficients, and energy absorption using the proposed bumper. An empirical relation amongst considered design parameters is formulated, which can be used to further develop the proposed modified bumper in any feasible ways. A comparative study has also been carried out between the crashworthiness of the conventional bumper and the developed bumper at various speeds. It is observed that a significant reduction of approximately 40% in the impact is observed with the proposed bumper compared to the conventional bumper. [ABSTRACT FROM AUTHOR]

Presence of cracks in mechanical components needs much attention, where the stress field is affected by cracks and the propagation of cracks may be occurred causing the damage. The objective of this paper is to present an investigation of crack type effect on crack severity in a finite plate. Three cases of cracked plate with three different types of cracks are assumed in this work, i.e., single edge crack, center crack and double edge crack. 2D numerical models of cases of cracked plate are established in finite element analysis (FEA), ANSYS software by adopting PLANE 183 element. Values of FEA mode I stress intensity factor SIF and Von-Mises stress at crack apex are determined for cases of cracked plate under tensile stress with different values. To identify the crack severity, the comparison of FEA results for different cracked cases is made. The comparison showed that, single edge cracked plate (SECP) has the maximum values of mode I SIF and Von-Mises stress at crack apex, i.e. the greatest crack severity is considered. Also, values of FEA Von-Mises stress at crack apex for center cracked plate (CCP) are moderate and for double edge cracked plate (DECP) are the minimum. Besides, in case of high crack lengths, it is found that, FEA results of mode I SIF in case of (CCP) are higher than those of in case of (DECP). Consequently, crack severity is considered as moderate in case of (CCP) and the minimum in case of (DECP). Empirical formulas are used to approximately estimate mode I SIF for all the case studies of cracked plate in this study and the results are compared to those of FEA. A good agreement between analytical and FEA results has been showed by this comparison

In this paper, deformation, Von-Mises stress, and failure analysis were carried out on a base stand using ANSYS workbench. The structural design was carried out using SolidWorks software and then imported into the ANSYS workbench for analysis. The investigation is performed using four different materials, i.e., structural steel, aluminum alloy, carbon fiber, and copper alloy, with an applied loading force of 1000 N at the tip of the structure. This technique highlights a complete reaction of the structure to the loading force, therefore providing room for structural optimization to reduce the risk of unexpected failure and unnecessary material wastage. The results obtained were compared and analyzed to identify the best material capable of withstanding the subjected force. Based on the Von-mises result, Carbon fiber has the highest possible maximum stress value of 4.70e+07 Pa, followed by structural steel, then Copper alloy. At the same time, the aluminium alloy has the least minimum Von-Mises. Structural steel is the very best option based upon the analysis outcomes. Its factor of safety is above unity in all the designs, which indicates that the structure has been over-designed. For that reason, it is suggested that the structure needs to be enhanced.

Machining of mechanical parts using material removal is one of the most used manufacturing techniques in the industry. This type of machining is a highly coupled thermomechanical process. During machining, the tool/chip interface is the site of complex interactions between mechanical, thermal and metallurgical phenomena. The experimental study remains difficult and expensive because of the multitude of parameters involved in the cutting phenomenon, which makes the use of finite element (FE) simulations an essential approach. In this work, a thermomechanical 2D model of the orthogonal cutting process of 42CrMo4 steel was developed using Abaqus/Explicit. The objective of this work is to study the influence of cutting parameters (feed f and cutting speed Vc) on cutting forces, stress distribution and temperature. A particular interest is given to the temperature and constraints of the cutting tool compared to similar work, particularly for 42CrMo4 steel. Knowing these two answers makes it possible to calculate the wear and thus the service life of the cutting tool. The results show that cutting speed and feed rate have a significant influence on cutting force, stress and temperature in the cutting zone. A comparison of the simulated and experimental results was carried out in terms of cutting force, to verify the accuracy and reliability of the developed simulation model. It was found that the average error on the cutting force is 8.11%, which proves the relevance and reliability of the proposed numerical model. [ABSTRACT FROM AUTHOR]

Background: Porous materials are recommended for orthopedic applications as they eliminate issues of interfacial instability with tissues and reduce mechanical mismatch of the young's modulus. Objective: The current research provides a finite element analysis (FEA) to investigate porous gyroid Ti6Al4V structure compared to a solid stem model for human tibial-knee implantation of total knee replacement (TKR). Material and Methods: In this study, the implant proximal portion was designed as porous gyroid Ti6Al4V structure with 500 µm pore size. CATIA V5R18 was used for modeling both gyroid and full solid models. Structural analysis was carried out using ANSYS R18.1 to evaluate the implant performance. Results: After gyroid implantation, the maximum von-Mises stress obtained under the tibial tray was increased to 10.081 MPa. Also, the maximum shear stress at the stem/bone interface was reduced to 0.7347 MPa. The stress concentration at the stem tip and the bone strain energy were also improved. The minimum factor of safety is 4.6 for the gyroid porous implant. A proof of concept model was additively manufactured successfully with pore size 577.7733 ± 34.762 µm. Conclusion: The results indicated enhanced clinical performance of the porous tibial-knee implant compared to the solid titanium implant via increasing the maximum von-Mises bone stresses and decreasing the maximum shear stress at the bone/implant interface. [ABSTRACT FROM AUTHOR]

Aim This study aims to comparatively evaluate the stress distribution and deformation in class II cavities restored with EverX posterior and Activa TM  Bioactive restorative material using three-dimensional finite element analysis. Methods On a mandibular first molar tooth model, features of a class II mesio-occlusal cavity were designed. Following the application of EverX Posterior and Activa TM  Bioactive, the model was subjected to a 600 N static occlusal load. Three-dimensional finite element analysis was used to analyze the distribution of occlusal stresses among the remaining components and restorative materials. von Mises and maximum principal stresses were evaluated and compared. Results von Mises and maximum principal stresses of Activa TM  Bioactive components were higher compared to the control group and EverX Posterior model. Activa TM  Bioactive restorations had absorbed more stresses within the material rather than distributing it to enamel and dentin than EverX Posterior material. Also, deformation was extremely high in the Activa TM  Bioactive model, which may be because of less stiffness of the material. Conclusion EverX posterior has a higher capacity to bear stresses in stress-bearing areas than Activa TM  Bioactive Restorative., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Bansal et al.)

Among the various structural optimization tools, topology optimization is the widely used technique in obtaining the initial design of structural components. The resulting topologically optimal initial design will be the input for subsequent structural optimizations such as shape, size and layout optimizations. However, iterative solvers used in conventional topology optimization schemes are known to be computationally expensive, thus act as a bottleneck in themanufacturing process. In this paper, a novel deep learning-based accelerated topology optimization technique with the ability to predict ductile material failure is presented. A Conditional Generative Adversarial Network (cGAN) coupled with a Convolutional Neural Network (CNN) is used to predict the optimal topology of a given structure subject to a set of input variables. Subsequently, the same cGAN is trained to predict the Von-Mises stress contours on the optimal structure by means of color transformed image-to-image translations. The ductile failure criterion is evaluated by comparing the cGAN predicted maximum Von-Mises stress with the yield strength of the material. The proposed novel numericalmethod is proven to arrive at the topologically optimal design, accompanying the material failure decision within a negligible amount of time but also maintaining a higher prediction accuracy. [ABSTRACT FROM AUTHOR]

Presence of cracks in mechanical components needs much attention, where the stress field is affected by cracks and the propagation of cracks may be occurred causing the damage. The objective of this paper is to present an investigation of crack type effect on crack severity in a finite plate. Three cases of cracked plate with three different types of cracks are assumed in this work, i.e., single edge crack, center crack and double edge crack. 2D numerical models of cases of cracked plate are established in finite element analysis (FEA), ANSYS software by adopting PLANE 183 element. Values of FEA mode I stress intensity factor SIF and Von-Mises stress at crack apex are determined for cases of cracked plate under tensile stress with different values. To identify the crack severity, the comparison of FEA results for different cracked cases is made. The comparison showed that, single edge cracked plate (SECP) has the maximum values of mode I SIF and Von-Mises stress at crack apex, i.e. the greatest crack severity is considered. Also, values of FEA Von-Mises stress at crack apex for center cracked plate (CCP) are moderate and for double edge cracked plate (DECP) are the minimum. Besides, in case of high crack lengths, it is found that, FEA results of mode I SIF in case of (CCP) are higher than those of in case of (DECP). Consequently, crack severity is considered as moderate in case of (CCP) and the minimum in case of (DECP). Empirical formulas are used to approximately estimate mode I SIF for all the case studies of cracked plate in this study and the results are compared to those of FEA. A good agreement between analytical and FEA results has been showed by this comparison.

In the machining world, development of predictive models is one remedy to reducing tool failure and its associated challenges like reduction in integrity of machined parts, production shutdown and idle time for machine operators. In this research, we want to show how robust the Finite Element (ANSYS) method is, by comparing its predictive capacity to the experimental machining operation. To achieve the scope of the study, Seventeen (17) varying set of experiments were conducted for the cutting tool using the three levels Box-Behnken’s design (BBD) of experiment at varying process parameters of 200-600 rpm spindle speed, 0.05-0.15mm/rev feed rate and 0.5 - 1.5mm depth of cut. During, the orthogonal cutting of AISI 1010 mild steel measuring 200mm length by 44mm diameter, the electrical strain gauge connected to the Electronic strain meter E10 was used to measure the tools’ induced strains from where the equivalent von mises stresses were generated for the research. The finite element software was then used to model the HSS tool for prediction of the concerned response based on the designed matrix generated by the Design Expert. The experimental values were compared with the ANSYS simulated values using the absolute mean percentage error and the reliability plot. At the end, both the experimental and FEM (ANSYS) readings were in close agreements with a mean absolute percentage error of 0.544%. Therefore, this research has clearly shown that ANSYS is a very robust expert tool that can be used to model and predict von mises stresses in HSS cutting tool. [ABSTRACT FROM AUTHOR]

BACKGROUND: There are many effective treatments for humerus shaft fractures caused by grenade throwing, such as non-operative treatment using hanging cast, operative treatment using locking plate, screw and intramedullary nail. However, it is reported by our team for the first time that using absorbable screw and ethibond suture for the treatment. OBJECTIVE: To evaluate the stabilization of fractures which are long-spiral humeral shaft fractures caused by grenade throwing fixed with absorbable screws and ethibond sutures in the method of finite element analysis, and provide evidence for clinical application. METHODS: CT data of humerus of a volunteer in Department of Orthopedics, 923 Hospital of Chinese People’s Liberation Army Joint Logistic Support Force were collected. Finite element models of the same fracture with different fixities which were limited contact dynamic compression plate (plate group), absorbable screws (screw group), and absorbable screws with ethibond sutures (combination group) were established. Three working conditions were set up: (1) humeral head was fixed and distal humerus was applied compressive force of 300 N. (2) Humeral head and distal humerus were fixed and the middle part was applied bending load of 350 N. (3) The humeral head was fixed and distal humerus was applied torsion load of 15 N•m. The maximum displacement of fracture surface, the average equivalent stress of fracture surface and the maximum equivalent stress of absorbable screw were assessed in three working conditions. RESULTS AND CONCLUSION: (1) Under compression, bending or torsion loading, the maximum deformations of fracture surface of the model in the screw group were 0.52, 0.27, and 0.544 mm, respectively, and 0.51, 0.25, and 0.396 mm in the model of the combination group. The maximum deformations of fracture surface of the model of the plate group were 0.495, 0.234, and 0.393 mm. (2) The mean values of von-Mises stress distribution of fracture surface of the model of the screw group were 5.964, 4.512, and 24.176 MPa, respectively. They were 5.651, 4.601, and 21.465 MPa in the model of the combination group, and 1.210, 4.048, and 13.537 MPa in the model of the plate group. (3) The total deformation in the plate group was the smallest, and that in the combination group was close to that in the plate group; the average effective stress of the fracture surface in the combination and screw groups was higher than that in the plate group. (4) The results verify that according to the results of the experiment in the method of finite element analysis, the fracture stability is satisfactory if using absorbable screws and ethibond sutures to fixate long-spiral humeral shaft fracture. Moreover, the stress-shielding effect is lower than that of dynamic compression plate, and advantageous for fracture union and preventing partial osteoporosis. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper Analytical plastic procedures for studying tension fields effects on intermediate beams in steel plate shear walls and estimating the plastic moments of horizontal boundary elements under equal and unequal top and bottom tension fields of SPSWs have been developed and compared with finite element analysis procedure by using ABAQUS software. The results indicate that with developing and increasing of tension fields, axial compression and shear forces are increased specially in unequal mode and subsequently in all models (3,5,7 story),were modeled by strip model (AISC design guide 20) and using von-mises yield criterion in plane-stress condition for finite element analysis, plastic moment capacity of critical selected beams are decreased and results from theoretical plastic analysis were shown to agree well with the results from finite element analysis that is shown that accuracy of classic plastic analysis in estimation of plastic moment of beams and it is noticeable that it is necessary to consider tension fields effects in plastic moment capacity and minimum required moment of inertia because of incresing and developing of tension fields and post-yielding of steel plates and subsequently affect on compress and shear beam stresses values and resistant moment design capacity in positive and negative flexure of horizontal boundary elements for ultimae loads.

Titanium alloys are used as an aerospace material due to their inherent properties such as high strength to weight ratio, corrosion, and fracture resistance. However, the low conductivity and reactivity towards plastic deformation causes these materials to be difficult to cut category. The prediction of various parameters like chip formation and actual cutting forces are important factors for better machinability which involves lot of resources. To overcome such issues, this work proposes three-dimensional FE approach to simulate the machinability behavior of Ti-6Al-4V especially on conventional turning. The impact of cutting speed and feed rate on the cutting force, thrust force, feed force and surface roughness were analyzed experimentally for various conditions. The predicted machining forces showed strong correlation with the experimental results and the effective von mises stress were examined. [ABSTRACT FROM AUTHOR]

Abstract Background Currently, cannulated pedicle screws have been widely used in minimal invasive or navigation techniques. However, the stress distribution and the strength of different core diameters of cannulated screw are not clear. This study aimed to investigate the mechanical strength of cannulated screws with different inner core diameter under various lumbar spine movements using finite element analysis. Results The results showed that the von-Mises stress of a cannulated screw was larger than that of a solid screw in all loading conditions, especially above 2 mm in cannulated core diameter. In lateral bending, extension, and flexion, the maximum von-Mises stress was found approximate to the proximal thread for all types of screws. In rotation condition, the maximum von-Mises stress was located at the middle of the screw. Additionally, the difference in stiffness of instrumented levels was not significant among four screws under the same loading condition. Conclusion Cannulated screws could provide enough stability for the vertebral body fusion comparing to solid screws. The diameter of cannulated core is suggested not to exceed 2.0 mm.

Aim and background This study aims to determine the stress distribution on the prepared tooth at the margins with shoulder and radial shoulder finish lines when an occlusal load of 300N was applied to ceramic, zirconia, and polyether ether ketone (PEEK) crowns. Materials and methods Six models of mandibular first molar teeth were fabricated. The tooth models were subdivided into two groups with shoulder and radial shoulder margins, respectively (n = 18). The teeth were restored with three different prosthetic crown materials (ceramic, zirconia, and PEEK). To simulate the typical forces experienced by a prosthetic crown material in a lower posterior tooth during chewing and biting, an occlusal load of 300N was applied to each of the samples, and the maximum principal stress (Pmax) and von Mises stress were calculated, respectively. These samples were then compared and evaluated to determine the material best suited as a prosthetic crown material of choice for a lower posterior tooth. Results Among the materials used, the maximum principal stress value was the least in PEEK crowns. The von Mises stress value was highest for the zirconia crown with shoulder margin and was least for the PEEK crown with a similar margin. Conclusion PEEK as a crown material was found to be a better choice for lower posterior teeth as there was the least maximum principal stress at the margin, irrespective of either shoulder or radial shoulder finish line used., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Hegde et al.)

The high-density polyethylene (HDPE) double-wall corrugated pipe, which is a kind of flexible pipe, is widely used in municipal drainage networks. The characteristics of the surrounding soil and pipe bed, pipe cover depth, backfill compaction, type of pavement and pavement design, and traffic loads are some of the major factors that affect the stress and deformation of pipes. In this study, the ABAQUS 3D finite element model was used to analyze the influence of backfill compactness, traffic loads, diameter, and hoop stiffness on the mechanical characteristic of an HDPE pipe under traffic loads. A series of full-scale tests were carried out to verify the validity of the simulation results. For the conditions tested, the results showed the following: (1) the Von-Mises stress of the pipe was mainly determined by the earth pressure at the crown, and the stress caused by backfill compaction increased significantly but had a short duration and limited impact on the pipe; (2) traffic load alone had little influence on the mechanical behavior of the pipe: while under the action of the loose backfill in contact with the pipe, the pipes were more sensitive to the traffic load response; (3) the fluctuations in the Von-Mises stress of the pipe mainly depended on the magnitude and speed of the traffic load; (4) for pipes with a small diameter, non-compacted backfill easily caused stress concentration in the pipe, while the degree of backfill compaction had almost the same effect on the distribution of stress for pipes with different hoop stiffness. [ABSTRACT FROM AUTHOR]