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Purposes Bird impact resistance has always been one of the important testing factors for aircraft airworthiness. In order to explore the bird impact resistance performance of civil aircraft nose side panel, three methods of rivet failure ratio assessment, energy method, and residual bearing capacity assessment are used to evaluate. Methods The effectiveness of the numerical model was verified by simulating the bird impact behavior of three types of side wall panels by using PAM-CRASH software, and the reliability of the above method was evaluated according to the bird impact failure of the three test specimens. Findings The research results indicate that the lower the proportion of rivet failures, the better the bird impact resistance of the structure; When the proportion of rivet energy absorption increases and the proportion of skin energy absorption decreases, the anti-bird-collision performance of the structure is improved; Among the above methods, the residual bearing capacity evaluation method can realize quantitative analysis of the bird impact resistance performance. The lower the damage factor value, the better the bird impact resistance performance of the side wall panel. Conclusions By summarizing the applicability and limitations of the bird impact performance evaluation method for side wall panels, this work provides valuable reference for the safety design and research and development of later civil aircraft.

Abstract The study presented focuses on material research of La Tène rivets and represents the very first study conducted into this class of archaeological finds from the Bohemian region. The rivets examined come from two significant archaeological sites situated in this geographical area—a hillfort Kolo near Týnec nad Labem and an oppidum in Stradonice. The sets of the rivets selected for the study were dated to the Late La Tène period (second–first century BC)—in the context of Western Europe, the term Celtic period can also be found. Thorough material research of the objects utilised a range of methods such as scanning electron microscopy with energy dispersive analyser, atomic absorption spectrometry, X-ray micro-tomography scanning, laser ablation-inductively coupled plasma-mass spectrometry, and Raman spectrometry. As a result, the research has identified and described three different technologies used to produce the rivets. The rivets uncovered there were mostly produced by casting from a bronze alloy or by putting wrought iron pins into the bronze melt of rivet heads. In addition, a minority of the rivets were produced using forged wrought iron with their heads plated with a very thin bronze plate. The results of the elemental analysis showed that several of the rivets and most of the rivet heads were made of bronze alloys with a tin content of 2–10 wt.%. The lead content of bronze alloy rivets from both sites varies from 0.2 to 10.1 wt.%. It can be assumed, that lead was intentionally added to the bronze melt used to produce the majority of the artefacts examined. Also, several bronze rivet heads were found to be decorated with enamel, which is a type of soda-lime-silica high lead glass coloured with crystals of Cu2O (the Colour of the enamel was predominantly red). In conclusion, two different groups of enamels were distinguished: (a) enamels with PbO up to 20% and (b) enamels with a higher content of PbO reaching up to 40%.

The study presented focuses on material research of La Tène rivets and represents the very first study conducted into this class of archaeological finds from the Bohemian region. The rivets examined come from two significant archaeological sites situated in this geographical area—a hillfort Kolo near Týnec nad Labem and an oppidum in Stradonice. The sets of the rivets selected for the study were dated to the Late La Tène period (second–first century BC)—in the context of Western Europe, the term Celtic period can also be found. Thorough material research of the objects utilised a range of methods such as scanning electron microscopy with energy dispersive analyser, atomic absorption spectrometry, X-ray micro-tomography scanning, laser ablation-inductively coupled plasma-mass spectrometry, and Raman spectrometry. As a result, the research has identified and described three different technologies used to produce the rivets. The rivets uncovered there were mostly produced by casting from a bronze alloy or by putting wrought iron pins into the bronze melt of rivet heads. In addition, a minority of the rivets were produced using forged wrought iron with their heads plated with a very thin bronze plate. The results of the elemental analysis showed that several of the rivets and most of the rivet heads were made of bronze alloys with a tin content of 2–10 wt.%. The lead content of bronze alloy rivets from both sites varies from 0.2 to 10.1 wt.%. It can be assumed, that lead was intentionally added to the bronze melt used to produce the majority of the artefacts examined. Also, several bronze rivet heads were found to be decorated with enamel, which is a type of soda-lime-silica high lead glass coloured with crystals of Cu2O (the Colour of the enamel was predominantly red). In conclusion, two different groups of enamels were distinguished: (a) enamels with PbO up to 20% and (b) enamels with a higher content of PbO reaching up to 40%. [ABSTRACT FROM AUTHOR]

Abstract—The research on ultrasonic riveting has revealed that the application of vibrations enables a significant decrease in the riveting force and changes the deformation characteristics of a rivet. Initially, a rivet shank undergoes upsetting, and the gap between the rivet and the installation hole is filled with the deformed metal, and a closing head then forms. The joints formed by ultrasound-deformed D18 alloy rivets exhibit a considerable increase in the shear force. [ABSTRACT FROM AUTHOR]

The influence of extremely low temperatures on the strength characteristics of adhesive-riveted joints made of aluminum of AMg3M grade with different types of polymeric materials is analyzed. [ABSTRACT FROM AUTHOR]

T‐stubs and L‐stubs loaded in tension are generally assumed in contact with a rigid foundation. The prying force and stiffness of these components depend on this hypothesis. For double web angle riveted connections, the angle rests on deformable beam/column web. The objective of the present paper is to take into account the effects of this deformability on the development of the contact area, the rivet forces and the tensile stiffness. An enhanced theory of beam in contact with a tensionless Winkler foundation is adopted in the contact and lift‐off areas. The axial and bending flexibilities of rivets are also considered. A numerical analysis is also performed with ANSYS in order to validate the analytical model. A sensitivity study is conducted on the influence of the thickness of the horizontal leg. The analytical and the numerical results are in good agreement, which confirms the accuracy of the proposed mechanical model. [ABSTRACT FROM AUTHOR]

A finite element model of damage accumulation in the joint's tensile process was developed in ABAQUS software to address the complex load transfer mechanism of the hybrid adhesive-riveted joint of the carbon fiber sandwich structure. The change in adhesive-riveted energy was used creatively to characterize the joint's load-sharing law after verifying the accuracy of the simulation results. In addition, the effects of load sharing and eccentricity on the joint's tensile performance were investigated. The results show that the adhesive load came before the rivet load, but increasing the number of rivets improved the proportion of rivet load and prevented the adhesive layer from failing. A greater number of rivets also reduced the fluctuation of eccentricity, which affected the tensile load and crack propagation. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Mechanics is the property of Chinese Journal of Applied Mechanics 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 recent years, the growth of tetraploid Sicilian wheat landraces has been arousing increasing interest. In this study, eighteen local genotypes of Triticum turgidum subsp. turgidum, belonging to the groups 'Bufala', 'Ciciredda', 'Bivona' and 'Paola', and two cultivars of Triticum turgidum subsp. durum (the old variety 'Bidì', and a more recent variety 'Simeto') were assessed for the characteristics of the grain and bread-making performance of their flours and doughs, as well as the quality of the loaves. The grain of the twenty genotypes came from a field trial conducted during 2018–2019 in south-eastern Sicily. The main commercial features of the grain (thousand kernel weight and hectolitre weight), including the defects (starchy, black pointed and shrunken kernels), were determined. The wholemeal flours and doughs obtained from the grain of each genotype were evaluated for the main technological quality (physico-chemical and rheological characteristics), and processed into loaves, whose main quality indices (volume, height, weight, moisture and porosity) were assessed. The results from such analyses allowed the authors to evaluate the genotypes' bread-making suitability. In particular, for the grain characteristics, hectolitre weight varied from 68.23 ('Bufala Rossa Lunga 01') to 77.43 ('Bidì 03') kg/hL, passing through the typical values for common and durum wheat. Among the grain defects, the black point defect was absent in all the grain samples, except for that of 'Bufala Nera Corta 01' (2%). Dry gluten content varied from 6.22 to 10.23 g/100 g, and sedimentation test values were low or medium-low, with values ranging from 22 to 35 mL. Amylase activity was low and highly variable among the genotypes, with the maximum value observed for 'Bufala Rossa Corta b01' (509 s). The doughs evidenced a poor quality for bread making with alveograph values of W ranging from 12 to 145 (10−4 × Joule) and thus the volume of the loaves varied from 346.25 cm3 of 'Bivona' and 'Ciciredda' to 415.00 cm3 of 'Bufala Rossa Lunga'. A Tandem Cluster Analysis was conducted on a set of all the response variables. The Hierarchical Cluster Analysis was initially run. A five-cluster solution identified three clusters further segmented and two single branches. Overall, the study highlighted the possibility of using some of these landraces alone for the production of traditional breads locally appreciated or together with other ingredients for the production of crumbly baked goods such as substitutes for bread and biscuits. [ABSTRACT FROM AUTHOR]

For lightweight materials, e.g. aluminium, the definition of proper joining technology relies on material properties, as well as design and manufacturing aspects. Substrate thickness is especially relevant due to its impact on the weight of components. The present work compares the performance of adhesively bonded (AJ) to hybrid riveted-bonded joints (HJ) using aluminium substrates. To assess the lightweight potential of these joining methods, the effect of substrate thickness (2 and 3 mm) on the lap-shear strength (LSS) of single lap joints is investigated. An epoxy-based structural adhesive is employed for bonding, whilst HJs are produced by lockbolt rivet insertion into fully cured adhesive joints. The stiffness of joints increased with an increase of substrate thickness. HJs presented two-staged failure process with an increase in energy absorption and displacement at break. For HJs, the substrate thickness changed the failure mechanism of rivets: with thicker substrates failure occurred due to shear, whereas in thinner substrates due to rivet pulling-through. The LSS of 2 mm and 3 mm-thick AJs is similar. With 2 mm-thick substrates, the LSS of HJs was lower than AJs. In contrast, the highest LSS is obtained by the 3 mm-thick HJs. The highest lightweight potential, i.e. LSS divided by weight, is achieved by the 2 mm-thick AJs, followed by the 3 mm-thick HJs with a loss of ca. 10% of specific LSS. [ABSTRACT FROM AUTHOR]

The Al/Mg dissimilar joints were obtained by welding-assisted riveting methods under different structural rivets on the basis of laser-arc hybrid welding source. The mechanical properties and elemental distribution of joints were investigated. When the rivet structure was straight, the maximum lap shear load of the joint was 3.7 kN. When the rivet structure was step rivet, the maximum lap shear load of the joint was 4.9 kN. The intermetallic compounds (IMCs) at the Al–Mg interface of the welded-riveted hybrid joint of the straight rivet were Mg2Al3 and Mg17Al12. The IMCs at the Al–Mg interface of the welded-riveted hybrid joint of the step rivet were Mg17Al12. There were more IMCs and more pores in the weld pool in the welded-riveted hybrid joint of the straight rivet. The welded-riveted hybrid joint of the stepped rivet structure had a small amount of Mg alloy and Al alloy melting at the Al–Mg interface, forming a transition layer of about 110 μm. Studies have shown that the distribution position of IMCs was the key problem affecting the performance of the welded-riveted hybrid joints. [ABSTRACT FROM AUTHOR]

Copyright of Duzce University Journal of Science & Technology is the property of Duzce University Journal of Science & Technology 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.)

A new friction-based riveting technique, Rotating Hammer Riveting (RHR), is demonstrated to fully form AZ31 Mg rivet heads in a mere 0.23 s. Heat and pressure generated through severe plastic deformation during the process was sufficient to form the Mg rivet head without the need for a pre-heating operation. Due to preliminary twinning and followed by dynamic recrystallization, AZ31 Mg grains in the rivet head were refined during RHR, which enhance the formability of Mg rivets by triggering grain boundary sliding and reducing plastic anisotropy of Mg. In addition, RHR joints showed a metallurgical bond between the rivet head and top AZ31 Mg sheet, which eliminates a significant pathway for corrosion.

This work aims to reduce the energy consumption of existing buildings through retrofitting and converting them into net zero energy buildings (NZEBs). Various retrofits for an existing academic building were modeled and analyzed using REVIT software. Energy consumption was reduced to approximately 34% through retrofits, and a Solar System of 41.6 kW was integrated to meet the reduced energy demand, consequently converting the building into an net zero energy building (NZEB). Furthermore, environmental and economic analyses were conducted, and the results show a reduction of 32.8 metric tons of CO2 emissions per year as a result of retrofitting the building, converting it into an net zero energy building. The building envelope retrofits and electrical appliances have a payback period of 2.96 and 2.62 years, respectively, whereas the proposed Solar System has a payback period of only 2.3 years. Moreover, the building was rated using the Leadership in Energy and Environmental Design (LEED) rating tool, and it qualifies for silver certification after retrofits and the integration of renewable energy sources (RES). The reduction in energy consumption and integration of renewable energy sources contribute to achieving Sustainable Development Goal (SDG) 7, and reduced CO2 emissions save climate variations, which leads to achieving Sustainable Development Goal 13.

Copyright of Bearing is the property of Bearing 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 recent years, the growth of tetraploid Sicilian wheat landraces has been arousing increasing interest. In this study, eighteen local genotypes of Triticum turgidum subsp. turgidum, belonging to the groups ‘Bufala’, ‘Ciciredda’, ‘Bivona’ and ‘Paola’, and two cultivars of Triticum turgidum subsp. durum (the old variety ‘Bidì’, and a more recent variety ‘Simeto’) were assessed for the characteristics of the grain and bread-making performance of their flours and doughs, as well as the quality of the loaves. The grain of the twenty genotypes came from a field trial conducted during 2018–2019 in south-eastern Sicily. The main commercial features of the grain (thousand kernel weight and hectolitre weight), including the defects (starchy, black pointed and shrunken kernels), were determined. The wholemeal flours and doughs obtained from the grain of each genotype were evaluated for the main technological quality (physico-chemical and rheological characteristics), and processed into loaves, whose main quality indices (volume, height, weight, moisture and porosity) were assessed. The results from such analyses allowed the authors to evaluate the genotypes’ bread-making suitability. In particular, for the grain characteristics, hectolitre weight varied from 68.23 (‘Bufala Rossa Lunga 01’) to 77.43 (‘Bidì 03’) kg/hL, passing through the typical values for common and durum wheat. Among the grain defects, the black point defect was absent in all the grain samples, except for that of ‘Bufala Nera Corta 01’ (2%). Dry gluten content varied from 6.22 to 10.23 g/100 g, and sedimentation test values were low or medium-low, with values ranging from 22 to 35 mL. Amylase activity was low and highly variable among the genotypes, with the maximum value observed for ‘Bufala Rossa Corta b01’ (509 s). The doughs evidenced a poor quality for bread making with alveograph values of W ranging from 12 to 145 (10−4 × Joule) and thus the volume of the loaves varied from 346.25 cm3 of ‘Bivona’ and ‘Ciciredda’ to 415.00 cm3 of ‘Bufala Rossa Lunga’. A Tandem Cluster Analysis was conducted on a set of all the response variables. The Hierarchical Cluster Analysis was initially run. A five-cluster solution identified three clusters further segmented and two single branches. Overall, the study highlighted the possibility of using some of these landraces alone for the production of traditional breads locally appreciated or together with other ingredients for the production of crumbly baked goods such as substitutes for bread and biscuits.

On the basis of laser-arc hybrid welding source, the welding assisted riveting hybrid bonding technology was adopted to realize the joining of AZ31B Mg and 6061 Al alloys. The fracture mechanism and the influence of the welding penetration on the mechanical properties were explored. The welded joint consisted of the Mg-Mg fusion zone and the Mg-Al reaction zone, the microstructure and the element distribution of these two areas were studied. The optimal mechanical property of the hybrid bonding joint was obtained at a penetration "H" of 2600 μm. The favorable stability of the joint was guaranteed by the "U"-shaped welded joints. The peak tensile shear load was 2.18 kN and the peak tensile strength was 173 MPa. A majority of homogeneous metals and a minority of dissimilar metals were found in the welded joints and the mechanical performance of the structure was enhanced by adding the rivets during the welding process. [ABSTRACT FROM AUTHOR]

Nearly all aluminum overhead truss sign structures (OHTSSs) in Kansas constructed before 2015 use an identical type of hot-riveted coupling assembly to provide connections between vertical poles and horizontal truss members. Although many of the connections have been in service for 30 to 40 years, no research has been conducted to determine their fatigue performance. This paper presents a study aimed at characterizing the fatigue performance of the coupler connections. The study includes a series of finite-element (FE) analyses and 24 experimental fatigue tests. The FE analyses were used to determine design-level fatigue demands on the coupler connections and to provide information for designing the experimental setups used in this test program. Four sign structures with three connection properties and six loading modes were modeled. The experimental tests were conducted to characterize the fatigue performance of the connection. Tests were conducted for three loading modes with respect to the load on the rivet connecting the two interior half-couplers: (1) tension, (2) vertical shear, and (3) horizontal shear. Results indicated that when loaded below 10 Ksi (68.9 MPa), the connection can be classified as a Category E′ based on stress in the rivet. The FE analyses and test results indicated that fatigue failures are unlikely to occur in the coupler connections used in OHTSSs. In addition, two used coupler assemblies from OHTSSs taken out of service were also tested and the failure surfaces were examined under a microscope. No reliable evidence of preexisting cracks was found. [ABSTRACT FROM AUTHOR]

A new friction-based riveting technique, Rotating Hammer Riveting (RHR), is demonstrated to fully form AZ31 Mg rivet heads in a mere 0.23 s. Heat and pressure generated through severe plastic deformation during the process was sufficient to form the Mg rivet head without the need for a pre-heating operation. Due to preliminary twinning and followed by dynamic recrystallization, AZ31 Mg grains in the rivet head were refined during RHR, which enhance the formability of Mg rivets by triggering grain boundary sliding and reducing plastic anisotropy of Mg. In addition, RHR joints showed a metallurgical bond between the rivet head and top AZ31 Mg sheet, which eliminates a significant pathway for corrosion. [ABSTRACT FROM AUTHOR]

To reduce weigh of the transportation machines, joining of the FRP and the light metal is considered as important technique. In this study, the punching rivet method was applied to make joints between a GFRP sheet and an aluminum alloy A6061 sheet and joint strength was examined. The punching rivet method is possible to join the sheets without drilling by using a rivet and a rivet holder. The punching-out process of the sheets using a rivet shank as a punch and the joining process of the sheets using the rivet and the rivet holder are continuously performed. From the experimental results of joining of the GFRP sheet and the A6061 sheet, the joints made by the punching rivet method had no large crack and out-of-plane deformation of the joints was suppressed. From the results of the joint strength tests, the joints made by the punching rivet method had almost the same joint strength as the bolted joints which were tightened by regulated torque. In addition, the fatigue life of the joints made by the punching rivet method was longer than that of bolted joints. It could be confirmed that the punching rivet method was effective to join the GFRP sheet and the A6061 sheet.

Enterohaemorrhagic Escherichia coli (EHEC) are food-borne pathogens responsible for bloody diarrhoea and renal failure in humans. While Shiga toxin (Stx) is the cardinal virulence factor of EHEC, its production by E. coli is not sufficient to cause disease and many Shiga-toxin producing E. coli (STEC) strains have never been implicated in human infection. So far, the pathophysiology of EHEC infection is not fully understood and more knowledge is needed to characterize the “auxiliary” factors that enable a STEC strain to cause disease in humans. In this study, we applied a recombinase-based in vivo expression technology (RIVET) to the EHEC reference strain EDL933 in order to identify genes specifically induced during the infectious process, using mouse as an infection model. We identified 31 in vivo-induced (ivi) genes having functions related to metabolism, stress adaptive response and bacterial virulence or fitness. Eight of the 31 ivi genes were found to be heterogeneously distributed in EHEC strains circulating in France these last years. In addition, they are more prevalent in strains from the TOP seven priority serotypes and particularly strains carrying significant virulence determinants such as Stx2 and intimin adhesin. This work sheds further light on bacterial determinants over-expressed in vivo during infection that may contribute to the potential of STEC strains to cause disease in humans.

Cold forming is a manufacturing process that plastically deforms metal using dies. It allows for high speed production, little to no material waste compared to conventional machining, and creates a stronger end product due to work hardening of the material. Cold working in forging process refers to the process of strengthening steel alloy by changing its shape without the use of heat. Subjecting the alloy to this mechanical stress causes a permanent change to the metal's crystalline structure, causing an increase in strength. At this time applied deformation rate, velocity and die design of product effect the mechanical features, flow-orientation properties of sample and load requirements for forging process of rivets. In this study, it is aimed to investigate the operation steps effect on formability characteristics of rivet produced by cold forming with the support of finite element method. Effective plastic strain, yield stress and forging force variations depending on die design were obtained by simufact.forming simulation software. Simulations made with different die designs and physical production results of these dies were compared. The effects of the number of forming operations and die cavity on the process were determined by performing material flow, hardness and structural analysis. [ABSTRACT FROM AUTHOR]

In order to improve the joint performance of a titanium alloy rivet connecting aircraft CFRP structure and promote the wide application of ordinary titanium alloy rivets in the aviation field, the ductility of a Ti45Nb rivet was improved using a current-assisted method in this paper. Through experiments, the mechanical behavior and temperature during the riveting process were monitored, and the variation rules of interference and damage were studied in detail. The results show that a current within 16.5 A/mm2 can effectively reduce the riveting pressure requirement, and the maximum engineering stress is reduced by nearly 22%. As the current density increases, the softening effect is obvious, but as the processing time increases, the softening effect has an upper threshold. The current-assisted method can significantly increase the interference fit level, and the uniformity of riveting can be improved by nearly 30%. The outlet burr height of a joint obtained by new technology meets the relevant standards. When the current density is too large or the action time is long, the damage pattern and mechanism at different depths of hole have obvious regional differences.

Today, the manufacture of engine and fuselage parts of flying platforms such as helicopters and aircraft is largely based on solvable and indecipherable joining techniques. Especially in parts where unsolvable joining techniques are used, adhesive is used in limited places, but to a large extent Rivet, welding and solder connections are used and work is being done on new, lighter and more durable joining processes with higher connection efficiency. Especially in these days when the construction of domestic and national aircraft and helicopters is being accelerated, the understanding of these joining techniques and joining philosophy on behalf of our country is of greater importance for our country’s engineers. In this study, information is given about joining technologies, materials and joining concept used extensively in the manufacture of aircraft and current technologies are explained. [ABSTRACT FROM AUTHOR]

Traffic patterns increasing and the degradation of existing roadway steel bridges due to poor maintenance has led to the need of an assessment deciding whether to retrofit or to supply a structure replacement. This paper focusses on the rehabilitation of steel truss bridges in order to extend the lifetime of such bridges. Two case studies are presented: the Adige Bridge, located between the provinces of Padua and Rovigo, and the Po Bridge, which connects the Rovigo and Ferrara provinces in northern Italy. In both cases, stress data and displacements are obtained by a 3D finite element model and the results show that loads defined in the European code are enough to compromise material strength in several sections. Appropriate retrofitting criteria are proposed and compared. A multi-criteria decision approach is introduced at the end of the paper to help in the decision-making process of selecting the best option for an additional reinforcement strategy, taking into account four criteria: reliability of the solution, ease of construction, estimated cost and embodied carbon. [ABSTRACT FROM AUTHOR]

Fatigue behaviour is one of the most important properties of modern airplanes and rivets influence it strongly. According to the literature, the NACA riveting offers a multiple increase in the fatigue life of joints.

Copyright of Bearing is the property of Bearing 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.)

Based on laser-induced tungsten inert gas hybrid welding source, the riveting–welding hybrid joining technology was applied to join Q460 high-strength steel and 6061 Al alloy. The mechanism of the action of hybrid welding source was discussed. The effect of welding penetration of the Al alloy sheet on mechanical properties and element distribution of hybrid joints was investigated. In addition, the formation mechanism of Al-steel interface was also explored. Under the action of laser-induced arc hybrid welding source, three load-bearing areas were generated in the joint, which were, respectively, the steel-steel welding joint, the Al-steel mixing area, and the Al/steel interface formed by the sidewalls of Al alloy plate and steel rivet. When the penetration of Al alloy "H" was between 300 and 400 μm, the tensile shear load of the hybrid joint was evaluated to 5.3 ± 0.2 kN, which was 90% of the strength of Q460 steel. In addition, the properties of joints were improved by the bonding effect of the Al alloy plate and steel rivet. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering 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 recent years, mechanical clinching has been widely used to join aluminium alloy sheets to build the automotive body. The high protrusion on the joint may limit the use of the mechanical clinching in the visible places. In order to get a lower protrusion, a compressing method was investigated in this work. Clinched joints with different geometrical parameters were used to conduct the experiments. AL5052 was taken as the material of the sheets. The protrusion of the clinched joint was compressed by two flat dies. A rivet placed in the pit of the clinched joint was used to control the metal flow in the compressing process. The top die moved downward to compress the protrusion, and the bottom die was fixed. The study shows that the tension-shearing strength and cross-tensile strength can be increased by the compressing method. The compressing method can increase the tension-shearing strength and cross-tensile strength by increasing the neck thickness. The compressed joint has larger neck thickness and lower protrusion than the clinched joint. Neck fracture mode is the main failure mode of the joints. The energy absorption can also be increased after the compressing process. [ABSTRACT FROM AUTHOR]

Due to the complexities of calculations based on different representations of constituent parts in an assembly, the combined improvement of efficiency and precision for the riveting has seldom been studied by the sequence planning or dimensional engineering. This article develops an assembly sequence optimization method that simultaneously minimizes the path length and overall dimensional error for the solid riveting. The sequence is denoted by the order of classifications for the nodes around the rivet holes in the finite element model for the assembly. Ant colony algorithm is applied on the optimization by integrating two calculations, that is, the length calculation of riveting path and the calculation of the dimensional error related to rivet upsetting directions and assembly sequence. Results for three assemblies are presented which show a good degree of optimization in performance for different scales of assemblies with different numbers of rivets that share the same solid riveting process. [ABSTRACT FROM AUTHOR]

In recent years, the application of fiber-reinforced plastics (FRPs) as structural members has been promoted. Metallic bolts and rivets are often used for the connection of FRP structures, but there are some problems caused by corrosion and stress concentration at the bearing position. Fiber-reinforced thermoplastics (FRTPs) have attracted attention in composite material fields because they can be remolded by heating and manufactured with excellent speed compared with thermosetting plastics. In this paper, we propose and evaluate the connection method using rivets produced of FRTPs for FRP members. It was confirmed through material tests that an FRTP rivet provides stable tensile, shear, and bending strength. Then, it was clarified that non-clearance connection could be achieved by the proposed connection method, so initial sliding was not observed, and connection strength linearly increased as the number of FRTP rivets increased through the double-lapped tensile shear tests. Furthermore, the joint strength of the beam using FRTP rivets could be calculated with high accuracy using the method for bolt joints in steel structures through a four-point beam bending test.

This study investigated the mineralization process of calcium carbonate on bamboo surfaces using aqueous solutions of calcium propionate and sodium carbonate as precursors. The mineralization process was carried out once, three times, and five times, and its effects on fire-retardant, mechanical, and mold-proof properties were examined. Scanning electron microscopy revealed that calcium carbonate bonded with bamboo cells through a rivet structure, resulting in a pronounced roughness of the mineralized layer. Mineralized bamboo exhibited improved fire-retardant properties, with decreases of the maximum heat release rate and total heat release rate by 20–32 % and 8–13 %, respectively. Additionally, mineralized bamboo displayed enhanced mechanical properties, increase of modulus of elasticity (MOE) and modulus of rupture (MOR) by 1–3 % and 3–10 %, respectively. After five cycles of deposition, the initial contact angle of the mineralized bamboo became 159°, and the infestation value of Aspergillus niger mold was almost zero, indicating satisfactory hydrophobicity and mold-proof properties. Mineralization of bamboo surfaces with calcium carbonate substantially improved the properties of bamboo and extended its application in various fields. [Display omitted] • Calcium carbonate bonds with bamboo cells by a rivet structure. • The depositional mode of calcium carbonate formation in parenchyma cells and vessels differs. • High calcium carbonate loading efficiency favors increased hydrophobicity. • Calcium carbonate promotes char residue formation and improves flame retardancy. • Calcium carbonate mineralization inhibits Aspergillus niger mold growth. [ABSTRACT FROM AUTHOR]