Lap Shear Tests Research Articles

Joining of additively manufactured fiber-reinforced thermoplastic and metals by ultrasonic energy: Mechanical and corrosion behavior

Ultrasonic joining (U-Joining) is applied to create reinforced hybrid joints between unreinforced or fiber-reinforced polymers and surface-structured metals. While the feasibility of joining additively manufactured (AM) materials was already demonstrated, a detailed description of the process parameters’ effects is still missing. Therefore, this study aims to define the influence of the U-Joining parameters on the mechanical and corrosion properties of AM 20% short-carbon-fiber-reinforced poly-ether-ether-ketone (PEEK-20CF) and 316L stainless steel (316L SS) hybrid joints. Optimal joining parameters were determined via Box-Behnken design of experiments to maximize the joints’ ultimate lap shear forces (ULSF) and displacement at break (DaB), where the results increased from 1.4 ± 0.2 kN to 3.6 ± 0.3 kN (2.6 times) and from 1.2 ± 0.3 mm to 2.4 ± 0.1 mm (2 times), respectively. Microstructural analyses revealed a strong micromechanical interlocking between the parts due to the filling of crevices at the as-built AM metallic part’s rough surface by consolidated PEEK-20CF, which resulted in a mixture of adhesive, cohesive and net tension failure during the lap-shear tests. Finally, the corrosion resistance was also evaluated by potentiodynamic polarization curves, showing that the energy input during the joining cycle slightly reduced the pitting corrosion resistance of the 316L part.

Experimental Investigation and Characterization of Friction Stir Spot-Welded Dissimilar Aluminum Copper Metallic Lap Joints.

Due to their contrasting physical properties, joining materials like copper and aluminum has always proven difficult. The disadvantages of traditional joining methods include additional weight, solidification problems, and energy waste. Friction stir spot-welding (FSSW) was utilized for joining copper and aluminum in order to get around these difficulties. This study illustrates that friction stir spot-welding (FSSW) produces joints between incompatible copper and aluminum alloys with better mechanical and electrical properties. The numerous FSSW parameters play an important role in deciding how well the welded joint performs. Tool rotational speed (TRS), plunge rate (PR), and dwell duration (DT) are the study parameters. During manufacture, a case-hardened H13 tool was used to lap-joint AA 6061 T6 hot-rolled aluminum flat strips with C11000 copper strips while operating at three different levels of TRS, PR and DT. SEM analysis was utilized to investigate the interface region and bimetallic interface of the joints. In order to demonstrate modifications in the grain-related characteristics, the joints were examined for electrical conductivity, mechanical strength (lap shear, bending, and microhardness test), and analysis of the microstructure at the weld zones. The outcome demonstrates that other factors, such as plunge rate, dwell time, and tool rotation speed, had the greatest impact on the joints' electrical conductivity, mechanical strength, and microstructure.

In Situ Observations of the Strain Competition Phenomenon in Aluminum Alloy Resistance Spot Welding Joints during Lap Shear Testing

The real-time evolution of the deformation and strain field of non-heat-treatable aluminum alloy 5754 and heat-treatable aluminum alloy 6061 resistance spot welding joints during the lap shear test was extracted using the digital image correlation (DIC) technique. The strain competition phenomenon between the nugget and its peripheral metal was quantitatively analyzed by applying 2D and 3D DIC analyses. The quantitative data show the tensile strain concentrated in the peripheral metal of the AA5754-O joint, which fractured in the pull-out mode. In comparison, a significant shear strain appears in the nugget of the AA6061-T6 joint, leading to its fracture in the interfacial failure mode during the lap shear test. The phase evolution of the nugget was analyzed using the thermodynamics database JMatPro, which was further used to calculate the local strength of the joints. The results indicate that the nugget strength of AA5754 is 223 MPa, the nugget strength of AA6061 is 178 MPa, and the heat-affected zone (HAZ) strength of AA6061 is 263 MPa. By inputting the local strength data, the calculated result of the analytical load-bearing competition model is in accordance with the experimental data of the lap shear test.

Structural reversible adhesives based on thiol-epoxy vitrimers

This work presents a family of functional adhesives based on covalent adaptable networks (CANs). Low-cost and commercially available monomers, including diglycidyl ether of bisphenol A, pentaerythritol tetrakis (3-mercapto propionate) and dipentaerythritol hexakis (3-mercapto propionate), were cured using a base catalyst to produce highly cross-linked materials. The catalyst selection and the study of the curing reaction were performed using differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The catalyst was chosen for better feasibility of industrial production, characterized by short curing times and relatively low temperatures. Thermal stability and thermomechanical properties of the final materials were evaluated through thermogravimetry (TGA) and dynamic mechanical thermal analysis (DMTA), respectively, revealing glass transition temperatures (Tg) higher than 50 °C. Stress relaxation tests were conducted to investigate the vitrimeric behaviour of the polymers, which exhibited an Arrhenius-type dependence of relaxation times on temperature. Importantly, both materials demonstrated impressive creep resistance up to 70 °C, indicating their suitability for use at elevated service temperatures. Tensile and lap-shear tests were also performed, revealing high lap-shear strength values (up to 16 MPa) comparable to those of commercial adhesives. Furthermore, these vitrimers displayed remarkable properties such as shape memory, shape reconfiguration, and self-welding capabilities, underscoring their excellent potential for a wide range of highly demanding applications in industrial production.

Methodology for evaluating the mechanical performances of a bonded assembly through complementary mechanical tests

ABSTRACT Bifunctional polymers have been studied as bonding layers (BL) on aluminum surfaces to promote adhesion of adhesives for structural bonding applications. The BL are located at the interface between the aluminum substrate and the adhesive. The mechanical performances of the BL in a bonded assembly were evaluated via several complementary mechanical tests, before and after ageing cycle: single lap shear, Arcan test, three-point bending test, and micro-scratch. The results of these four mechanical tests were compared with those of a raw reference (without any treatment) and a reference that had undergone standard surface preparation (cleaning and etching), in order to assess the mechanical performances of the surface treatment products (BL), and to value these products on the surface treatment market. In order to follow a methodology for selecting the best surface treatments, the mechanical results were compared with each other, and even correlated for samples with bonding layers (containing phosphorus and carboxylic acid functions). The correlation of the results obtained from the four mechanical tests (single lap shear, Arcan, three-point bending, and micro-scratch tests) therefore makes it possible to validate the methodology for evaluating these surface treatments.

A study of adhesive bonding in metal–metal, metal–CFRP, and CFRP–CFRP material combinations under shear deformation: Fracture morphologies and damage mechanisms

Safe design of adhesive joining in multi-materials in engineered structures requires the accumulation of numerous experimental data on the failure behavior of various adhesively-bonded material combinations under different loading conditions. The deep understanding of mechanical performance, fracturing morphologies, and main damage mechanisms is also quintessential for accelerating the development of proper physics-based and multi-scale models for assisting the design.Towards this goal, this work presents a comprehensive characterization of the failure behavior of adhesively-bonded metal–metal, metal–CFRP, and CFRP–CFRP material combinations under global shear deformation via single lap shear testing. Thanks to a synergistic combination of measurement methods by using Digital Imaging Correlation (DIC) and 3D optical profilometry, adhesive features on the adherend after failure were quantified and the main progressive damage mechanisms were identified.The characterization performed in this work provides quantitative data that contributes to a better understanding of shear failure in adhesive bonding across different bi-material combinations. The obtained results have practical implications, including the potential to enhance adhesive bonding design, identify failure causes in adhesive joints, and develop or validate computational models capable of capturing the observed behavior in various adhesively-bonded materials under global shear deformation.

Semi-analytical mechanical model for FRCM-to-substrate shear bond tests

The debonding process of an FRCM reinforcing system from the substrate is studied in a semi-analytical fashion. FRCM is modeled considering independently the central elastic fiber grid and the two thick upper and lower matrix layers, assumed elasto-fragile; matrix and fiber are considered in a monoaxial state of stress; they mutually exchange shear stresses at the interface, this latter characterized by a softening stress-slip relationship; the reinforcement system is then bonded with a rigid substrate by means of a further elastic interface. Under such hypotheses, a simple system of first order non-linear and coupled differential equations is derived and solved by means of a semi-analytical approach. Independent variables are the axial displacements of the three layers (upper and lower matrix, central fiber) and the corresponding axial stresses. The approach is successfully validated against two experimental datasets available in the literature, relying into different FRCM strengthening systems bonded to rigid substrates and subjected to single lap shear tests. The model is able to capture not only the global debonding behavior but also the local one, with a precise prediction along the bond length of the shape of the axial stresses into the different layers, of the interface shear stresses and of the location of the cracks inside the matrix.

Structural behaviour of Cold‐Formed Steel back‐to‐back welded sections subjected to longitudinal shear

AbstractThe current study focuses on understanding the behaviour of flare v‐groove welds on back‐to‐back connected Cold‐Formed Steel welded sections (G300) subjected to longitudinal shear. A novel welding technique called Cold Metal Transfer (CMT) welding was used for fabrication with copper‐coated steel welding wire as a filler metal (ER70S‐6). This mode of welding has the advantage of controlled material deposition compared to the spray or globular mode of welding. Lap shear tests were carried out on unlipped channels including thickness of the weld, and length of the weld. The weld geometry was observed under an optical microscope after polishing and chemical etching of the weld cross‐section, as American Iron and Steel Institute (AISI) design standard provides no specification on thickness of flare v‐groove welds for CMT welding process. In general, the lap shear specimens failed in plate tearing failure mode and brittle fracture of weld at the weld contours. Additionally, the appropriateness of AISI's shear design strength equations for flare v‐groove welds was verified and preliminary design guidelines are provided addressing the lacunae in AISI design standard.

Experimental Analysis on Ultrasonic Resistance Spot Welding of Aluminum Alloys

A recently developed hybrid joining process known as ultrasonic resistance spot welding (URW) was used on various pairs of similar and dissimilar aluminum (Al) alloys with different thicknesses, including AA5182–AA5182, AA6111–AA6111, AA7075–AA6111, and AA7075–AA5182, and comprehensively studied. Compared to conventional resistance spot welding (RSW), URW of the alloys showed consistently enhanced mechanical behavior in lap shear and crosstension tests. This can be attributed to the multiple perspectives on microstructure improvements. For different stacks of Al alloys and welding conditions, nugget formation was promoted with a larger nugget size in URW. In the nugget center, ultrasonically assisted (UA) vibration facilitated the formation of an equiaxed crystal zone. At the nugget boundary, URW showed a narrower coarse columnar zone and partially melted zone, which are associatedwith the lowest hardness in the weld. Specifically in dissimilar Al welds, UA vibration moved the nugget more centered toward the weld interface. These microstructure improvements indicated UA vibration can homogenize temperature and elemental distribution, which modifies solidification behavior.

Fatigue life assessment and fracture mechanisms of additively manufactured metal-fiber reinforced thermoplastic hybrid structures produced via ultrasonic joining

Ultrasonic Joining (U-Joining) produces through-the-thickness reinforced (TTR) hybrid joints between thermoplastics and surface-structured metals. The joining parameters were previously optimized to join additively manufactured (AM) 316L stainless steel (316L SS) and 20% short-carbon-fiber-reinforced poly-ether-ether-ketone (PEEK-20CF) to maximize the joints' performance under quasi-static lap shear testing. However, further investigations on the joint's fracture mechanisms and cyclic loading performance are still lacking. Therefore, this study describes the stress distributions, assesses the fracture mechanisms and evaluates the fatigue life of AM 316L SS/PEEK-20CF hybrid joints. A finite element model was developed to clarify the joints' mechanical behavior, and their fatigue performance was assessed under cyclic tensile condition. The fatigue tests were performed at different percentages of the reached ultimate lap shear force (ULSF) and analyzed via two-parameter Weibull distribution and load-life curves for different reliability levels. The results showed that a fatigue life of 1 × 106 cycles could be reached when a load of 1.52 kN, or 42% of the ULSF, is applied, demonstrating the joints' high mechanical performance and potential for engineering applications. Joints reaching the one million cycles threshold were stopped at this mark and tested under quasi-static lap shear to assess their residual force. The results significantly decreased from 3.6 ± 0.3 kN to 2.4 ± 0.5 kN for ULSF and residual force, respectively. Fractography analyses identified polymer delamination, partial TTR pull-out, and interfacial/net-tension failure as the main fracture mechanisms. Polymer detachment in fatigue specimens indicated the influence of secondary bending at low load levels, explaining the reduced residual force.

Nano-silika ve GNP Hibrit Nanoparçacık Takviyeli Tek Bindirmeli Bağlantıların Kesme ve Kırılma Özellikleri

In the current study, the effects of hybrid nanoparticles on the shear and fracture behaviours of adhesively bonded single lap joints (SLJs) using Aluminum substrates were investigated. To this aim, nano-silica and graphene nanoplatelet (GNP) particles were used as filler materials in Araldite 2014-2 epoxy-based adhesive. The SLJ samples prepared at seven different configurations were subjected to lap shear tests. Additionally, macro and SEM views taken from damaged surfaces of the samples were examined to understand the influence of nanoparticle addition on the fracture characteristics of the joints. The experimental findings showed that all nanoparticle-doped samples, whether single or hybrid, exhibited remarkable improvements in shear strength compared to pure ones. The maximum improvements were obtained from the H2 sample having 1 wt.% nano-silica and 0.5 wt.% GNP. The maximum shear strength was 13.62 MPa which was 213% higher than pure samples (4.35 MPa). It was determined that some toughening mechanisms such as crack deviation, crack bridging and plastic void formations had a crucial role in the enhancements of the samples. However, higher amounts of nanoparticle inclusion such as H4 (1.5 wt.% nano-silica+1 wt.% GNP) showed a decrease in shear strength, compared to the maximum one, due to the material degradation caused by agglomerations. In conclusion, nano-silica and GNP particles proved they could be used together by exhibiting a synergetic effect in the adhesive joints.

The aging characteristics of resistance rivet welded aluminum/steel joints

The aging characteristics of Al/UHSS resistance rivet welding (RRW) joints are investigated for the first time in this paper. Microstructure studies have shown that the aging treatment does not change the phase composition of the Al/steel mixed nugget still remaining the ferrite structure, while the precipitation, growth and dissolution occur for the microstructure of Al alloy varying with the distance from the rivet. Mechanical tests revealed that for interfacial fracture (IF) and button pullout fracture (BPF) joints, the maximum peak load increased by 13% and 26% with the prolonged aging time, respectively. The improvement in the joint strength after aging can be attributed to the relaxation of the residual stress for IF joint and the age hardening of Al sheet for BPF joint. In addition, interestingly, the accelerated artificial aging is discovered firstly in Al/steel RRW joint. The phenomenon can be attributed to the higher solid solubility of Mg and Si in softening zone of Al sheet, resulting in faster and more precipitation during the aging treatment. The precipitation kinetics indicated that the average Avrami exponent was 1.25, proving the one-dimensional linear growth of fresh nuclei of the hardening phase β''. The block shear model analysis suggested that the Canadian Standards Association, giving the calculating/test values ratio ranged from 0.88 to 1.08, could provide a more reasonable calculation, which showed that the shear failure was mainly determined by the yield of the gross shear plane, and the tension plane failed because of tensile rupture during the lap-shear test.

Mechanism of Pressure-Sensitive Adhesion in Nematic Elastomers.

Nematic liquid crystal elastomers (LCEs) have anomalously high vibration damping, and it has been assumed that this is the cause of their anomalously high-pressure-sensitive adhesion (PSA). Here, we investigate the mechanism behind this enhanced PSA by first preparing thin adhesive tapes with LCE of varying cross-linking densities, characterizing their material and surface properties, and then studying the adhesion characteristics with a standard set of 90° peel, lap shear, and probe tack tests. The study confirms that the enhanced PSA is only present in (and due to) the nematic phase of the elastomer, and the strength of bonding takes over 24 h to fully reach its maximum value. Such a long saturation time is caused by the slow relaxation of local stress and director orientation in the nematic domains after pressing against the surface. We confirm this mechanism by showing that freshly pressed and annealed tape reaches the same maximum bonding strength on cooling, when the returning nematic order is forming in its optimal configuration in the pressed film.

Refill friction stir spot welding of thermoplastic composites: Case study on Carbon-fiber-reinforced polyphenylene sulfide

Refill Friction Stir Spot Welding (refill FSSW) is an innovative solid-state welding technique that has been successfully applied to various combinations of metallic materials. The objective of the present study is to investigate the feasibility of refill FSSW for polymer–polymer structures, with a specific emphasis on carbon-fiber-reinforced polyphenylene sulfide (CF-PPS). The influence of the key joining parameters, i.e. force, plunge depth, rotational speed, and tool diameter, has been analyzed in terms of the resulting joint microstructure, mechanical strength, and failure mechanisms. The lap shear tests revealed two primary failure modes: interfacial shear failure and nugget pull-out. Fracture surfaces exhibited broken fibers. The depth of the joint was found to play a crucial role in determining the failure mode, with interfacial shear failure resulting in higher lap shear strength. Thermal analyses conducted on the produced joints showed no evidence of thermal degradation, which aligns with the temperature measurements during the process, as they remained below the melting temperature of CF-PPS.

Introducing a new approach for designing advanced epoxy film adhesives with high mechanical, adhesion, and thermal properties by adding hybrid additives for structural bonding

BackgroundEpoxy-based adhesives are widely used in different industries in various forms. Among them, epoxy film adhesives are particularly applicable in constructing honeycomb structures in aerospace systems. However, these adhesives suffer from brittleness, low flexibility, and thermal stability. In the current paper, the effect of pure and functionalized SiO2 and ZrO2 nanoparticles (NPs), the addition of a block copolymer (butyl acrylate-block-styrene), and Novolac resin on the mechanical, thermal, and adhesive properties of the epoxy film adhesive were thoroughly studied. MethodsThe mechanical properties, thermal stability, and surface morphology of the epoxy adhesive samples were evaluated using tensile, thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FE-SEM) images, respectively. More importantly, the Lap shear and Peel tests were utilized to investigate the adhesive properties. Significant findingsPure and functionalized NPs were added to the prepared epoxy adhesive samples. Intriguingly, compared to the non-functionalized NPs, by only adding 1 phr of each functionalized NPs to the formulation, the tensile modulus, tensile strength, and toughness increased to 66 %, 197 %, and 553 %, respectively. More importantly, the single lab shear and T-peel strength were increased as high as 121 % and 101 %, respectively, indicating a synergistic effect. After optimizing the parameters effective on the properties, FE-SEM images of the fractured surface of optimized samples were used to study the possible fracture mechanisms, including crack deflection, crack pinning, nanoparticle debonding, and shear band formation. Also, this synergistic effect was observed in the thermal stability where the only addition of 1 phr of functionalized NPs increased the decomposition onset temperature up to 40 ℃ higher than the neat one. This simple and applicable method can pave the way for using functionalized NPs in modifying epoxy adhesives.

Investigation of expandable fillers for reversible adhesive bonding in photovoltaic modules

Photovoltaic (PV) is a sustainable energy source and an efficient tool towards CO2 neutrality. However, recycling of PV modules remains challenging due to the strong connection of the multi-material assembly. The present work aims at the development of disbonding concepts for adhesive connections used in PV modules to enable improved recyclability and repairability of such modules. To achieve stimuli-responsive adhesive connections, thermally expandable fillers were implemented in a condensation-curing alkoxy-based silicone adhesive. 10–50 wt% of expandable graphite (EG) as well as 10–50 wt% of thermally expandable microspheres (TEM) were incorporated to obtain a controlled expansion of the adhesive at elevated temperature. The expansion ratio in dependence on time and temperature was examined. Furthermore, nanoscale magnetite (Fe3O4) passivated with a layer of SiO2 was added to the formulation to trigger the expansion of TEMs, and therefore separation of adhesive bonds by inductive heating. In this approach an efficient heating and expansion of the adhesive layers was feasible by applying an external alternating magnetic field with a ring coil. Aging stability, influence of filler content and expansion of the adhesive layers were further evaluated in lap shear tests. The addition of functional fillers decreased the bond strength by approximately 50% for adhesive layers containing 50 wt% EG. In contrast, adhesives with 50 wt% TEM exhibited a higher bond strength (by 10%) compared to the unfilled silicone system. Thermally triggered expansion significantly lowered the bond strength (20–30%) for TEM-filled adhesives and led to separation for EG-filled adhesives. Temperature cycling tests had no influence on the filled and unfilled adhesive's strength, whereas after damp heat tests all samples exhibited a lower (less than 40% of the unaged, pristine reference samples) but similar bond strength.

Experimental investigation on mechanical strength of adhesively bonded 3D-printed joints under hygrothermal conditions using Taguchi method

Despite several experimental, analytical, and numerical attempts to evaluate the hygrothermal impacts of the metal and composite adherents, the effects of hygrothermal effects on the adhesively bonded 3D-printed component have not been sufficiently investigated in the literature. With this motivation, this work aims to experimentally investigate the mechanical strength of adhesively bonded 3D-printed joints under hygrothermal conditions. To accomplish this goal, the joints having different surfaces and adhesive types were subjected to different durations. Taguchi L16 (42 × 21) orthogonal array was chosen as the experimental plan, and the single lap shear tests were conducted to evaluate the effects of the parameters on the joint strength. Polylactic acid (PLA) was used as adherends, and the adherends were manufactured by fused deposition modeling technique. Analysis of variance (ANOVA) was conducted to identify the correlations between variables, and also regression analysis is performed to show the suitability of experimental measurements. The results revealed that the adhesive type is the most influential parameter (60.76%) on single lap strength, followed by aging duration (23.62%), whereas the surface pattern (1.85%) shows no significant influence. The optimal set of parameters and levels is found as Loctite EA 9466 adhesive, 45° surface pattern, and no aging duration. The current study also revealed that the Taguchi method demonstrated its reliability as a predictive tool for assessing joint strength in hygrothermal environments.

Villi Inspired Mechanical Interlocking for Intestinal Retentive Devices.

Intestinal retentive devices have applications ranging from sustained oral drug delivery systems to indwelling ingestible medical devices. Current strategies to retain devices in the small intestine primarily focus on chemical anchoring using mucoadhesives or mechanical coupling using expandable devices or structures that pierce the intestinal epithelium. Here, the feasibility of intestinal retention using devices containing villi-inspired structures that mechanically interlock with natural villi of the small intestine is evaluated. First the viability of mechanical interlocking as an intestinal retention strategy is estimated by estimating the resistance to peristaltic shear between simulated natural villi and devices with various micropost geometries and parameters. Simulations are validated in vitro by fabricating micropost array patches via multistep replica molding and performing lap-shear tests to evaluate the interlocking performance of the fabricated microposts with artificial villi. Finally, the optimal material and design parameters of the patches that can successfully achieve retention in vivo are predicted. This study represents a proof-of-concept for the viability of micropost-villi mechanical interlocking strategy to develop nonpenetrative multifunctional intestinal retentive devices for the future.

Enhanced strength and toughness of repurposed glass fiber reinforced adhesive joints for sewage applications

ABSTRACT In this study, the enhancement in strength and toughness of multi-piece glass fiber reinforced plastic (GFRP)/GFRP joints was demonstrated. These joints are bonded with repurposed short glass fiber reinforced adhesive and find their application in rehabilitation of sewage pipelines. These short fibers were produced by grinding and milling the fiberglass wastes, collected during the lamination process of pipes. To study the effect of glass fiber content on the mechanical properties of the composite adhesive, short fiber composite (SFC) specimens with varied milled fiber content were tested under flexural loads. A finite element-based numerical homogenization study was carried out on a micro-mechanical periodic unit-cell representing a non-homogeneous SFC to predict the mechanical properties of the microstructure. The dispersion state of fibers and fracture surface characteristics of SFC were analyzed via scanning electron microscopy. Further, the shear strength of the adhesive with and without reinforcement was experimentally evaluated using a lap shear test. Increasing the fiber content in the adhesive transforms it from a compliant state with poor strength into a much stiffer and stronger composite with reduced strain tolerance. The optimized SFC was selected for joining the two segments of the GFRP sewage pipe using a unidirectional composite as a tongue. Subsequently, the tongue-in-groove joints (TGJs) were tested under tension.

A mechanical properties and failure mechanism study for resistance spot welded AHSSs under coach-peel and lap-shear loads

Based on mechanical tests, microstructure characterizations and finite element simulations, the mechanical properties and failure mechanisms of resistance spot welds (RSWs) were investigated in the study. Different types (B1500HS, 340/590DP, 420/780DP and 820/1180DP) and thicknesses (1.2–1.8 mm) of steel plates were welded as coach-peel (CP) samples. To quantify the effect of plate thicknesses on the failure bending moment, MCP, of CP samples, a new parameter, standardized failure bending moment, MSCP = MCP /T1 /T2, was introduced. Based on the new revealed relationship between the MSCP and low strength metal plate tensile strengths (LSMP σb), a MCP prediction model was provided. Moreover, the lap-shear (LS) test data (standardized shear strength, σSS) published in a previous work were also analyzed. With the increment of σb values (<800 MPa), σSS and MSCP parameters increased linearly. When the σb values > 800 MPa, the slopes of σSS and MSCP fitting lines were decreased. The similar variation trends of σSS and MSCP parameters implied similar RSW failure mechanisms. The new revealed relationship between the RSW minimum hardness values (Hmin, measured from base metals or heat affected zones) and LSMP σb values can explain the trends. Finally, by simulations analyses, the effect of different loading conditions on the mechanical performance of RSWs was also studied. CP loads induced the most severe stress concentration near the RSWs, which can severely weaken RSW mechanical performance.