Maximum Shear Load Research Articles

Numerical and experimental analysis of shear strength on SLM 3D-printed stainless-steel bonded joints enhanced by bio-inspired surface pattern

The performance of adhesive joints is significantly influenced by the surface texture of the adherends, making texture a crucial factor in their analysis and optimization. Existing literature on numerical modeling of bonded joints predominantly focuses on smooth surfaces, often neglecting the impact of surface patterns. As a result, there is limited understanding of how complex surface textures affect joint performance. Advanced surface textures, such as those inspired from biomimetic systems, have the potential to enhance joint strength. This study addresses this gap by developing two numerical models: one representing a smooth surface (without-texture) and another incorporating a biomimetic fish-scales (FS) texture. The models use Cohesive Zone Modeling with a local approach to simulate the effects of surface texture and adhesive behavior on block-shear joint performance. These models were validated through experimental block-shear tests on P1000 (polished with 1000-grit abrasive paper) and FS-textured stainless-steel joints. Experimental results demonstrated that the FS texture significantly improved joint strength by approximately 44% compared to the P1000 surface. This enhancement is attributed to better adhesive anchoring and extended contact area. Numerical results indicated that the model without-texture exhibited significant stress concentrations at the edges of the overlap, suggesting failure initiation in these regions. However, the FS texture caused repetitive stress peaks along the overlap, and the vertical walls of this texture effectively hindered crack propagation at the interface. Additionally, both models accurately predicted the maximum shear load and failure modes of the P1000 and FS bonded joints, demonstrating good agreement with experimental results, particularly for the hyper-elastic adhesive behavior.

A novel dissimilar resistance spot welding of Ti6Al4V alloy and 316L stainless steel via copper as interlayer by using optimal electrodes

A novel dissimilar resistance spot welding of Ti6Al4V alloy and 316L stainless steel was performed via copper as interlayer by using optimal electrodes. A significant improvement in nugget morphology being of less defects was achieved with increasing the copper interlayer thickness from 50 μm to 400 μm. Thinner interfacial reaction layers at both the nugget/titanium interface and the nugget/stainless steel interface and finer equiaxed dendritic grained structure at the inner nugget were formed with copper interlayer thickness of 300 μm compared with those without interlayer. The formation of TiCu and Ti2Cu was facilitated with the incorporation of Cu into the nugget, which effectively inhibited the formation of the brittle Ti–Fe intermetallic compounds including Fe2Ti. The nugget in the welded joint with copper interlayer in 300 μm thickness exhibited a far lower microhardness than that of the interlayer-free welded joint, and the average microhardness reduced to 604 HV in the inner nugget, which was about 36% lower than that of the interlayer-free welded joint. The tensile shear load of the welded joint exhibited an increased tendency with increasing interlayer thicknesses from 50 μm to 300 μm, and the maximum tensile shear load of 6.3 kN was obtained with the interlayer thickness of 300 μm, which was ∼97% higher than that of the interlayer-free welded joint. The welded joint with copper interlayer exhibited hybrid ductile and fragile fractured characteristics. The work would provide a facile and cost-effective method to achieve a reliable welded joint of Ti alloy and stainless steel.

Сompression and Shear of an Ideal-plastic Wedge with a Rough Stamp (Frictional Contact Model)

The transfer of shear force through frictional contact on rough surfaces of precompressed plastic bodies is studied. As a contact model, we consider the problem of plastic compression of a wedge by a rough flat stamp with the condition of Prandtl friction on the contact surface. A technique is proposed for determining the maximum shear load perceived by frictional contact.

Experimental and Numerical Characterization of the In-Plane Shear Behavior of a Load-Bearing Hollow Clay Brick Masonry System with High Thermal Performance

Modern masonry systems are generally built with hollow clay bricks with high thermal insulating properties, fulfilling the latest sustainability and environmental criteria for constructions. Despite the growing use of sustainable masonries in seismic-prone countries, there is a notable lack of experimental and numerical data on their structural behavior under lateral in-plane loads. The present study investigates the in-plane shear behavior of load-bearing masonry walls with thin bed joints and thermal insulating hollow clay blocks. Shear-compression tests were performed on three specimens to obtain information about their shear strength, displacement capacity and failure modes. The experimental characterization was supplemented by three shear tests on triplets, along with flexural and compression tests on the mortar for the thin joints. Furthermore, two Finite Element (FE) models were built to simulate the shear-compression tests, considering different constitutive laws and brick-to-brick contact types. The numerical simulations were able to describe both the shear failure modes and the shear strength values. The results showed that the experimental shear strength was 53% higher than the one obtained through Eurocode 6. The maximum shear load was found to be up to 75% greater compared to similar masonry specimens from the literature. These findings contribute to a better understanding of the potential structural applications of sustainable hollow clay block masonry in earthquake-prone areas.

Interfacial microstructure and mechanical property of dissimilar resistance spot welded joint of TC4 titanium alloy and 316L stainless steel with nickel interlayer

Dissimilar materials of TC4 titanium alloy and 316L stainless steel were joined by means of resistance spot welding with nickel interlayer in different thicknesses. A significant enhancement in terms of nugget morphology quality with less defects was achieved for the welded joints with nickel interlayer compared with that without interlayer. With increasing the nickel interlayer thickness from 50 μm to 300 μm, the effective nugget diameter increased gradually from ∼4.8 mm to ∼5.2 mm, which was lower than that of the interlayer-free welded joint being ∼5.9 mm. A thinner intermetallic compound layer with dual-layered structure features with thickness of ∼11 μm was formed at the nugget/titanium interface in the welded joint with nickel interlayer compared with that of the interlayer-free welded joint, meanwhile an intermetallic compound layer with thickness of ∼3 μm was formed at the nugget/stainless steel interface, which exhibited serrated structure features. The introduction of nickel interlayer in the welded joint could suppress the formation of the brittle Ti–Fe intermetallics such as Fe2Ti, and facilitate the formation of TiNi, Ti2Ni and TiNi3. A more homogeneous current density distribution and a lower peak temperature (1809 °C) during welding were achieved via employing nickel interlayer. With increasing nickel interlayer thickness from 0 μm to 300 μm, the tensile shear load of welded joints experienced an increased tendency first and then decreased, meanwhile the maximum tensile shear load of 3.7 kN was obtained with the interlayer thickness of 200 μm, which was 61% higher than that of the interlayer-free welded joint.

An experimental study of cold-formed steel connections with screwed clip angle under tension and shear loads

This paper aims to investigate the performance of typical cold-formed steel (CFS) beam-to-beam connections between floor bearers and floor joists through a series of full-scale experiments. The investigated connections consisted of a lipped channel (floor joist), an unlipped channel (floor bearer), a thin-walled clip angle (connector), and a self-drilling screw (fastener). In this study, customised T-shaped and H-shaped CFS connection specimens were tested to examine the performance under tension and shear loads, respectively. Two sizes of self-drilling screws, 10 G and 14 G, were used with the selected load bearing clip angle. The fabricated connection specimens were subjected to displacement-controlled tension and shear loads. The experiments uncovered the ultimate connection strengths, load-displacement relationships, and failure mechanisms of the designed CFS connections under the applied loads. Moreover, the experimental tensile and shear strengths of the connections were compared with the strengths predicted by the standard design equations. It was found that the screw pullout on the anchored leg of the clip angle was the main mode of failure under the tensile load. On the other hand, two different failure modes—fracturing of 10 G screws or shear buckling of the cantilevered leg of the clip angle with 14 G screws—were observed in the H-shaped specimen under the applied shear load. Among the designed connection specimens, the maximum tensile load capacity was 30.86 kN and the maximum shear load capacity 88.15 kN. The standard design calculations predicted screw pullout failure under tension, while the shear bucking failure mode of the clip angle under shear load was overlooked.

Extrinsic-Riveting Friction Stir Lap Welding of Al/Steel Dissimilar Materials.

To obtain high-quality joints of Al/steel dissimilar materials, a new extrinsic-riveting friction stir lap welding (ERFSLW) method was proposed combining the synthesis advantages of mechanical riveting and metallurgical bonding. SiC-reinforced Al matrix composite bars were placed in the prefabricated holes in Al sheets and steel sheets, arranged in a zigzag array. The bars were stirred and mixed with Al sheets under severe plastic deformation (SPD), forming composite rivets to strengthen the mechanical joining. SiC particles were uniformly dispersed in the lower part of the welding nugget zone (WNZ). The smooth transition between the SiC mixed zone and extrinsic-riveting zone (ERZ) ensured the metallurgical bonding. The maximum tensile shear load of the joints reached 7.8 kN and the maximum load of the weld per unit length was 497 N/mm. The fracture occurred at the interface between the rivets and steel sheets rather than the conventional Al/steel joining interface. Moreover, ERFSLW can prolong the service life of joints due to three fracture stages. This method can be further extended to the welding of other dissimilar materials that conform to the model of "soft/hard".

Evolution of bonding mechanism and fracture mechanism of Ti alloy-steel joint by dual-beam laser welding using Mg-RE (RE=Gd, Y) filler

In this paper, a novel coaxial continuous-pulsed dual-beam laser was proposed to join TC4 titanium alloy with QP980 high-strength steel, and magnesium alloy containing rare-earth elements (Mg-RE) was creatively as filler. The weld appearance, microstructure and mechanical properties of joints obtained by single-beam and dual-beam laser welding were compared and analyzed. And the evolution of bonding mechanism and the fracture mechanism with laser beam energy density was analyzed. The results showed that the appearance and mechanical strength of the joint obtained by dual-beam laser were better than that by single-beam laser. And the maximum tensile shear load of TC4/QP980 lap joint welded by dual-beam laser reached 303 N/mm, which was 124 % of that of single-beam laser welding. The bonding of Mg-RE with QP980 affected by temperature of laser welding and mainly depended on Gd and Y. They just diffused to QP980 under low power and reacted with Fe under high power. And the inter-diffusion of Zr of Mg-RE with Ti of TC4 produced to the bonding of Mg-RE with TC4. The roles of continuous laser and pulsed laser in dual-beam laser welding were revealed in this paper and it showed a great application potential of coaxial dual-beam laser welding technology in dissimilar metal joining.

Multi-indicator optimization of riveting joint forming quality of aluminum alloy sheets based on response surface test

In this paper, the effects of the interaction between punch diameter, die depth and punch speed on the quality of riveted joints are investigated using the BBD response surface test method. The results show that the mold depth has the greatest influence on the key dimensional parameters of riveted joints, followed by the punching speed, and then the punch diameter, while the punch diameter and the mold depth are the two factors with the most obvious interaction. The optimum riveted joint process parameters determined are punch diameter of 5.24 mm, die depth of 1.44 mm, and stamping speed of 5.00 mm/s. The corresponding relative errors predicted by numerical simulation and response surface optimization objective are 5.96 % for neck thickness, 3.29 % for interlocking value, and 1.37 % for bottom thickness; and the relative errors predicted by experimental results and optimization objective are 13.42 % for neck thickness, 13.42 % for interlocking value, and 1.37 % for bottom thickness. 13.42 %, interlock value is 4.23 %, and bottom thickness is 2.23 %, the model accuracy is high, and the optimization method of response surface test can effectively improve the quality of riveted joints. Through numerical simulation, the metal flow law and stress distribution during the riveting and forming process of aluminum alloy plate were analyzed, and the strength test of riveted joint was carried out, and the maximum destructive shear load of the joint was 1.8 KN, and the strength of the joint was improved, which verified the validity of the response surface optimization method.

Effect of rivet arrangement on fatigue performance of electromagnetic riveted joint with [formula omitted]10 mm diameter rivet

Electromagnetic riveting (EMR) can effectively form large-diameter rivets and produce high-quality joints. In this paper, the effect of rivet arrangement on fatigue performance of electromagnetic riveted joint was investigated. Quasi-static shear tests, fatigue tests, numerical simulation and microstructure observation were carried out. The results showed that the rivet arrangement had little effect on the shear performance and had a great impact on the fatigue performance of the EMR joint. Specifically, the difference between the average maximum shear load of the V-joints (60.49 kN) and the H-joints (60.41 kN) was small. The fatigue life of the H-joints was higher than that of the V-joints at high fatigue load levels (Fmax>30.225 kN), while the result was opposite at low fatigue load levels (Fmax<30.225 kN). Furthermore, the fatigue fracture analysis showed that there were two typical failure modes for the joints: (I) the rivet fracture, and (II) the sheet fractured on the manufactured head side. The V-joints mainly displayed the coexistence of failure mode I and mode II, while the H-joints displayed failure mode II at all fatigue load levels. At high fatigue load levels, the significant stress concentration in both rivets resulted in the rivet fracture of the V-joints within a relatively short time. Due to multiple extension directions and a smaller extension zone, the fatigue life of H-joints was lower than that of the V-joints at low fatigue load levels. Therefore, the fatigue performance of the component could be improved by choosing a different rivet arrangement.

Mechanical properties of an elastically deformable cervical spine implant

Anterior cervical surgery is widely accepted and time-tested surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the high adjacent segment degeneration rate and implant subsidence after the surgery using the traditional polyetheretherketone cage. Thus, we creatively designed a polyurethane cervical implant that can continuous load-sharing through elastic deformation and decrease postoperative stress concentration at adjacent segments. In this study, the design rationality and safety of this novel implant was evaluated based on several mechanical parameters including compression test, creeping test, push-out test and subsidence test. The results showed that the novel cervical implant remained intact under the compressive axial load of 8000 N and continues to maintained the elastic deformation phase. The minimum push-out load of the implant was 181.17 N, which was significantly higher than the maximum compressive shear load of 20 N experienced by a normal human cervical intervertebral disc. Besides, the creep recovery behaviour of the implant closely resembled what has been reported for natural intervertebral discs and clinically applied cervical devices in literature. Under the load of simulating daily activities of the cervical spine, the implant longitudinal displacement was only 0.54 mm. In conclusion, this study showed that the current design of the elastically deformable implant was reasonable and stable to fulfil the mechanical requirements of a cervical prosthesis under physiological loads. After a more comprehensive understanding of bone formation and stress distribution after implantation, this cervical implant is promising to be applied to certain patients in clinical practice.

The nonlinear analysis of reactive powder concrete effectiveness in shear for reinforced concrete deep beams

Abstract The aim of this article is to investigate the effect of using reactive powder concrete (RPC) for reinforcement concrete deep beams (CDBs) to study the shear effect by the numerical analysis. The method of finite element analysis model simulations using a program was used. The characteristics of RPC and the deep beam of reinforced concrete were obtained from previous scientific research. Non-linear analysis for two models of deep beams, one with RPC and the other without using it, was conducted to compare with experimental results from recent tests of deep concrete beams with RPC and loaded until failure. The data obtained from the specimens have many factors related to the effect of the strength and action of reinforcement CDBs such as shear load deflection, crack pattern, mode failure, and concrete strength. On the other hand, the mesh changing was investigated in terms of the maximum concrete strength and the running time by changing the mesh size to 50, 25, and 15. Models were simulated with a two-point load using a shear span-to-depth with an av/d ratio of 0.77. The difference in percentage deflection between the numerical and experimental models’ data was observed at 2.60 and 5.9% for concrete deep beam and RPC deep beam, respectively, and the maximum shear load was 2.27 and 5.40%. The importance of the outputs of this article lies in bridging the research gap of this new topic and identifying the shear behavior of deep beams reinforced with RPC due to the lack of research related to this topic. It was noted that the obtained data for finite element analysis are very consistent with the previous laboratory scientific research, while the error rate did not exceed 10%.

Resistance element welding of aluminium alloy and steel using an element of aluminium

Aluminium alloy AA6061 and mild steel Q235 were welded by resistance element using an aluminium rivet as the element. The microstructure and properties of the joints were characterised. The temperature distribution on the cross-section of the joints was calculated by using ABAQUS numerical simulation software. The observation results on the cross-section of the joints show a nugget formed at the interface between the rivet tip and steel of lower plate. The maximum tensile shear load of the joints reached 5.82 kN at the welding current of 26 kA. This study reveals that the bearing interface of the resistance element welded joint between aluminium alloy and mild steel is like-to-like interface of aluminium alloy which strengthens the joint.

Investigation of the failure mechanism of dissimilar resistance spot welding of steels

Austenitic and duplex stainless steels are majorly preferred for heat exchangers and chemical containers. This research work investigated the failure mechanism of dissimilar welded joints of AISI 347 and DSS 2205. The welded specimens were investigated using tensile shear tests, cross-tension tests, coach peel tests and microhardness tests. The specimen absorbed a maximum tensile shear load of 18 kN during the tensile shear test, and the failure mode was button pull-out with brittle fracture. The test sample absorbed a load of 15.1 kN during the cross-tension test, and the failure mode was button pull-out with brittle fracture. During the coach peel test, the sample absorbed a maximum load of 4 kN and ductile fracture was observed at the vicinity of the nugget. The failure mode in the coach peel test was of button pull-out type. The microhardness test recorded a maximum hardness of 312.8 HV, which is 78.74 and 7.1% higher than the base metal hardness values of AISI 347 and AISI 2205, respectively. The specimen failed under pull-out failure mode in all the tests, and hence, the weld zone was intact in all specimen arrangements and loading conditions.

Effect of edge riveting on the failure mechanism and mechanical properties of self-piercing riveted aluminium joints

In order to improve the use of aluminium alloys in lightweight automotive body panels, the failure mechanism and mechanical properties of AA5052 aluminium alloy sheets under different conditions were investigated by means of self-piercing riveting (SPR). The impact of riveting position on the structural strength, absorbed energy and instantaneous stiffness of self-piercing riveted connections was analyzed using the edge riveting method. Four edge distances of 1.65 mm, 2.65 mm, 3.65 mm and 4.65 mm were considered for the experimental study, and the riveted structure was analyzed and tensile shear tests were carried out by comparing the mechanical properties. The results indicated that this riveting method changed the failure mode of the joint, with the rivet pulling out from the lower sheet to a co-existence of rivet pull-out and riveted mouth sheet breakage; the maximum shear load, absorbed energy and deformation resistance decreased as the distance from the riveting point to the strip edge decreased; and the strength of the riveted joint based on the upper plate was significantly greater than that based on the bottom plate at the same edge pitch, and the stability of the joint is superior. This study provides a theoretical basis for the damage suppression of aluminium alloy edge riveted joints and the lightweight production of vehicles.

Friction Stir-Spot Welding of AA5052-H32 Alloy Sheets: Effects of Dwell Time on Mechanical Properties and Microstructural Evolution

Friction stir-spot welding (FSSW) as a solid-state joining process for local welding offers a number of benefits for applications in the automotive, aerospace, and marine industries. In these industries, and from an economic point of view, producing spot welds at a low rotating speed and in a short time is critical for saving energy and enhancing productivity. This investigation helped fill a knowledge gap in the literature about FSSW of 4 mm similar lap joints of AA5052-H32 sheet materials, in which welding takes place over a short time period with a slow tool rotation speed. Consequently, the purpose of this work was to investigate the feasibility of FSSW 2 mm thick AA5052-H32 aluminum alloy sheets to produce 4 mm thick similar spot lap joints at various low dwell times of 1, 2, and 3 s and a constant relatively low tool rotation speed of 500 rpm. The introduced heat input for the friction stir-spot welded (FSSWed) lap joints was calculated based on the applied processing parameters. Joint appearance, cross-section macrostructures, and microstructure features of all the spot welds were evaluated. The mechanical properties (hardness contour maps and maximum tensile shear loads) were also examined. The results show that joining 2 mm sheet thickness AA5052-H32 at a low heat input in defect-free similar lap joints could be successfully achieved. The stir zone (SZ) region became wider as the dwell time increased from 1 to 3 s. The hardness value of the SZ was higher than that attained by the AA5052-H32 base material (BM) for all applied dwell times. Especially at 2 s, the hardness of the SZ was approximately 48% higher than that of the BM. This increase in hardness may be attributed to the high grain refinement of the new dynamically recrystallized grain (4 µm) in the SZ compared to the cold-rolled BM grain size (40 µm). Among the tried FSSW process variables, the dwell time of 2 s at a rotation rate of 500 rpm also produced the maximum tensile shear load of 4330 N. Finally, the locations and features of the fracture surfaces of the FSSWed joints were examined using a scanning electron microscope (SEM) and the obtained results were discussed.

Research on the hybrid joining process and failure mode of laser welding and riveting on QP980 steel/CFRP

Combining the advantages of riveting and laser welding methods, and the characteristics of stepped rivets, excellent QP980 steel/CFRP weld-rivet hybrid joint joints were obtained and the effects of different laser powers on the welded joints were investigated. It was found that this welding method can reduce the damage to CFRP by heat input and obtain joints with favorable mechanical properties with maximum tensile shear load over 10 kN. Three failure characteristics of joints with this hybrid joining process were found: failure of steel joint, failure of CFRP, and failure of both steel joint and CFRP. The stress distribution characteristics in case of CFRP failure were simulated with ABAQUS. Different heat inputs resulted in different melting amounts of steel and CFRP, and these melted materials entered the assembly gap due to thermal expansion, thus changing the load-bearing characteristics of the hybrid joint. This load-bearing structure is not just a simple riveted and welded structure, but also forms a mechanical interlocking effect.

Microstructure and texture evolution of aluminum and titanium ultrasonic welded joints

Aluminum and titanium alloy joints were fabricated by ultrasonic welding (USW). The interface microstructure and mechanical properties of the Al/Ti joint were investigated. A relatively sufficient metallurgical bonding was achieved at the welding time of 0.3 s, after which the fracture pattern of the joint transformed from interfacial failure to nugget pull-out failure, and the shear load reached a stable level, with a maximum lap shear load of 3650 N. Electron backscatter diffraction (EBSD) was performed to analyze crystallographic characteristics in the faying interface. It revealed that dynamic recrystallization (DRX) mainly occurred at the interface of the Al side owing to severe plastic deformation and heat generation.

Exceptionally strong boron nitride nanotube aluminum composite interfaces

We report the direct strength property measurements along boron nitride nanotube (BNNT) aluminum (Al) composite interface using in situ scanning electron microscopy single-nanotube pullout techniques. The nanomechanical measurements reveal that the BNNT-Al interface possesses an average interfacial shear strength of ∼46 MPa and a maximum shear load of ∼340 nN, and is over 60% stronger than the comparable carbon nanotube (CNT) -Al interface. This strong interface enables significant loading of the nanotube during pull-out from the metal matrix with a generated maximum tensile stress close to its intrinsic strength limit. Density functional theory (DFT) calculations reveal stronger interfacial physio- and chemisorption interactions on an oxidized Al interface with hexagonal boron nitride (hBN) as compared to graphene, which are in contrast to comparable binding properties of hBN and graphene with pure Al. The exceptional Al-BNNT strength properties can thus be attributed to a partially oxidized metal-nanotube binding interface, which has important implications for optimizing the local interfacial load transfer and bulk properties of BNNT-metal nanocomposites.

Protrusion friction stir spot welding of dissimilar joints of 6061 aluminum alloy/Copper sheets with Zn interlayer

• All of joints generated via PFSSW illustrated a surface approximately free keyhole. • Maximum tensile shear load was obtained 3.2 kN and at 2500 rpm with Zn interlayer. • Brazed zone was affected by tools rotation speed while a dendritic structure was observed at 1600rpm. The dissimilar AA6061/pure Cu sheets were welded using a Zn foil via the protrusion friction stir spot welding (PFSSW) process. It was indicated that increasing the tool rotating speed enhanced the hardness of the stir zone from 55 to 78 HV. Furthermore, the results showed that all of the joints generated by PFSSW failed by IF mode, which can be ascribed to the presence of segregated Cu particles and brittle phases. The sample welded with 2500 rpm exhibited a maximum tensile shear load (3200 N).