Lap Shear Tests Research Articles

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.

Formation mechanism and mechanical strength evaluation of hybrid riveted/solid-state bonded aluminium alloy joint

In this research, an improved friction self-piercing riveting (F-SPR) process with internally threaded rivet and flat die was proposed to achieve hybrid riveted/solid-state bonded connection for low-ductility aluminium alloys. Instead of relying on rivet shank flaring to form mechanical interlock in the existing F-SPR process, a reliable threaded connection was established between the rivet shank and sheets by rapid filling of sheet material into the rivet thread grooves. A perfectly flat joint bottom was formed without inducing large-scale sheet distortion. A series of experimental tests were performed to clarify the joint quality characteristics, formation mechanism and mechanical performance. The results revealed that the quality of newly formed five aluminium threads demonstrated a decline trend from bottom to top. Two kinds of thread formation mechanisms were identified: The mechanism I is solely composed of Filling step and applied to upper four threads; The mechanism II consists of Filling-Fracturing-Welding steps and is applied to the lowest thread. Discontinuous solid-state bonding was formed at the sheet interface around the rivet shank periphery, whilst a bowknot-liked solid-state bonding zone with a weak welded zone and an unwelded zone was formed at the joint centre. Rivet pull-out failure from the bottom sheet was observed for the studied AA7075-T6 joints under both lap-shear and cross-tension loads. The peak loads reached 9.79±0.23 kN and 5.41±0.15 kN in the lap-shear and cross-tension tests, and the corresponding energy absorption was 13.82±0.59 J and 16.42±0.87 J.

Laponite stabilized endogenous antibacterial hydrogel as wet-tissue adhesive

Clinical adhesives for suture-less wound closure remain the problem of poor biocompatibility, weak adhesive strength, and no endogenous antibacterial ability. Here, we designed a novel antibacterial hydrogel (CP-Lap hydrogel) consisting of chitosan and ε-polylysine after being modified with gallic acid (pyrogallol structure). The hydrogel was crosslinked by glutaraldehyde and Laponite via Schiff base and dynamic Laponite-pyrogallol interaction, free from heavy metal and oxidants. Given its dual crosslinking feature, the CP-Lap hydrogel exhibited adequate mechanical strength (150–240 kPa) and demonstrated swelling and degradation resistance. For a typical lap shear test with pigskin, the apparent adhesion strength of the CP-Lap hydrogel could be enhanced to ∼30 kPa benefiting from the O2 blocking effect provided by nanoconfinement space between Laponite. In addition, the hydrogel showed effective antibacterial properties and excellent biocompatibility. The results indicated that this hydrogel has great potential for wound-closing bioadhesives to avoid chronic infections and further harm.

Finite Element Analysis of Sn-58Bi Shear Test

Finite element analysis (FEA) of quasi-static single lap shear test was conducted to study the mechanical properties of Sn-58Bi in terms of deformation, strain, stress, yield strength and ultimate strength. The study generated results of simulated behaviour of low temperature Sn-Bi solder alloy to address the demand of low temperature solder alloys in the electronic industry. The geometry was constructed in SolidWorks based on ASTM D1002 standard before being imported to ANSYS. The simulation was conducted at shear velocity of 0.1, 0.5, 1 and 1.27 mm/min and temperature of 138, 178, 208 and 238 °C using ANSYS. The simulation results were compared with the corresponding experimental results. Simulation results showed that an increase in shear velocity caused a decrease in ultimate strength and an increase in ductility of Sn-58Bi. As the velocity increased from 0.5 to 1.27 mm/min, the ultimate strength decreased from 339.87 to 291.24 MPa. This is predicted due to the Bi-rich layer within the lamellar structure of Sn-Bi alloy. An increase in temperature caused an increase in ultimate strength and brittleness in Sn-58Bi due to the trans-granular propagation of brittle failures along the weak Bi-abundant phase. As the temperature increased from 138 to 238°C, ultimate strength increased from 290.46 to 298.93 MPa.

Identification of the influence of micro two-stage refilled friction stir spot welding with variation dwell time on dissimilar brass CuZn30-aluminum AA1100

Welding and joining of brass CuZn30-aluminum AA1100 were obtained using micro two-stage refilled friction stir spot welding (mTS-RFSSW), which was carried out to eliminate the holes formed by the micro friction stir spot welding (mFSSW) process. The mTS-RFSSW process begins with the mFSSW welding process using tools with a pin inner diameter of 2.69 mm, pin outer diameter 1.811 mm and shoulder diameter of 4.954 mm, followed by a second stage process called mTS-RFSSW, which is a hole closing process using a tool with a pinless tool with shoulder diameter 4.954 mm. This study aimed to determine the effect of the second stage of dwell time on the mechanical properties produced in the mTS-RFSSW welding technique using brass CuZn30 and aluminum AA1100 with a thickness of 0.42 mm. In this study, the variable parameter is the second stage dwell time which varies from 3 s, 4 s, 5 s, and 6 s, respectively. An optical microscope that aims to observe the macrostructure shows that an upward hook is formed in each joining process. Based on the scanning electron micrograph, the resulting formation of different intermetallic compounds (IMC) with varying thicknesses occurs in every variation of dwell time. The high dwell time indicates discontinued IMC, which affects the tensile force. The IMC formed at the interface of brass CuZn30 and aluminum AA1100 is dominated by more than 30 % Cu. The highest hardness value is found in the stir zone because the formation of intermetallic compounds influences refined grains. The highest maximum shear force and cross tensile force was obtained 371.35 N and 54.88 N, respectively, in the dwell time of 3 s. The result of fracture properties after the lap shear test shows the presence of small dimples with microcracks that indicate brittle failure