Papers by Keyword: Shear Strength

Abstract: This study investigated the microstructure and melting point of the Zn–Al composite electroplating film. The cross-sectional microstructure and shear strength of the joints made from the plating films were also evaluated. Zn and Al were confirmed in the plating films from initial microstructure observation. The plating film prepared by a plating bath without cationic surfactant melted near the melting point of Zn and the eutectic point of Zn–Al. When jointed at a joining temperature of 443°C, joining pressure of 5 MPa, and holding time of 5 min, multiple intermetallic compounds, Zn–Al eutectic layers, and unreacted Al particles were observed in the joint layer. From quantitative analysis, the multiple intermetallic compounds were estimated to be Zn–Ni and Zn–Al–Ni intermetallic compounds. The shear strength of the joints increased with increasing joining pressure but was lower than that of Sn–5Sb solder. Fracture after the shear test was observed at the interface between unreacted Al particles and Zn–Al–Ni intermetallic compounds, and inside unreacted Al particles.

Abstract: Today, the design of polymer parts by additive manufacturing subjected to large stress has undergone a clear advance with the new concept of continuous fiber-reinforced thermoplastic composites (CFRTPC). The optimization of fiber alignment is the main asset to improve strength and has been widely discussed by the research community. In this work, the effect of the intercalation of the polymeric matrix (ONYX) between layers of continuous fiberglass reinforcement has been analyzed in shear specimens. Onyx is nylon mixed with short carbon fibers. The results show how inserting polymeric layers among the continuous fiber ones improves the shear strength up to 25% and the stiffness modulus up to 18%.

Abstract: Asymmetrical Four Point Bend test method is proposed for measurement of interlaminar shear strength in continuous fiber reinforced ceramic composites. The current standard ASTM test method (ASTM C1425) for interlaminar shear strength of composites uses a double edge notched compression (DNC) coupon. Large variation in measured strength is observed with the standard ASTM test method, possibly due to machining variability and damage at the notches. The proposed test AFPB method for ILSS is adapted from ASTM C1469 Standard Test Method for Shear Strength of Joints of Advanced Ceramics. This test method does not require any machining of notches and the sample size requirement is much smaller than the ASTM test method. The shear loading in this method is similar to the standard short beam shear test (ASTM D2344) with higher shear to tensile ratio compared to SBS with AFBP. Using finite element analysis, coupon geometry and the distance between the loading and support pins was optimized to maximize shear and minimize tensile and compressive stresses on the specimen. It was found that the variability in the measured ILSS strength was lower with this method compared to the ASTM standard method using the DNC specimen. In addition, the value of ILSS measured using AFPB method was found to be consistently higher than that measured using DNC coupons. It was also found that specimen preparation (cutting, polishing, etc.) did not have significant effect on the measured strength.

Abstract: Shear behavior of reinforced concrete beams using steel lathe scrap waste and end hooked steel fibers as fully or partially web shear reinforcement replacement was studied. Steel lathe scrap waste is generated from industrial steel waste and can be used as recycled fibers offering additional advantages towards environmental pollution reduction. To investigate their effect of reinforced concrete beam under shear behavior, ten reinforced concrete beam specimens with 1200 mm long, 200 mm wide, and 300 mm high were tested under quasi-static loading (two-point loading). The studied parameters in this investigation were types of fibers such as steel lathe waste fiber and traditional hooked steel fiber ratio and the web shear reinforcement ratio are zero% and 50%. Results observed were initial and post-cracking stiffness, maximum capacity load, vertical displacements, modes of failures, and the ductility of the specimens. It was concluded that using of steel lathe scrap waste and hooked steel fibers in concrete are advantageous, they changed the mode of failure of the beam from a brittle to a ductile mode of failure due to the ductility of steel used, whether traditional steel fiber or steel lathe waste fiber. The optimum ratio of the steel lathe scrap waste was found equal 0.5% while the optimum ratio of traditional hooked steel fiber is 1% as fractional volume.

Abstract: Fused Deposition Modeling (FDM) is one of the most common polymer 3D printing technologies used in many applications today. However, limited volume capacity for 3D printing large parts or components is the usual downside of this technology, especially desktop 3D printers. Hence, to offset this limitation, the 3D-printed parts are often designed in multiple pieces and assembled after printing, which requires post-processing called cold welding. Such welds are also quite strong but not as strong as a single-piece print. Therefore, finding suitable parameters or settings that can provide substantial strength for cold-welded 3D-printed parts will be beneficial. This study aims to determine the failing behavior and shear strength of ABS FDM 3D-printed single-lap joint using ABS glue as adhesive. Specimens were printed with varying raster angles (+45^o/-45^o and 0^o/90^o) and layer thickness (290 μm, 190 μm, and 90 μm) to investigate the effects on the adhesion or shear strength and failure mode of the acetone welded 3D-printed joints. Results show that raster angle and layer thickness significantly affected the shear strength of acetone welded materials. Single-lap joint test sample printed with +45^o/-45^o raster angle reveals higher shear strength than specimens printed with 0^o/90^o raster angle. Results also indicated that the gaps between the raster and voids between adjacent filaments of 3D-printed parts affects the adhesion and failure mode of a single-lap joint.

Abstract: This research was conducted to investigate the effect of variations in tool rotation and surface roughness towards shear strength on the newly developed friction lap welding (FLW) for dissimilar joints between stainless steel (SS) 304 and Nylon 6 plates. Under constant welding traverse speed at 30 mm/min, the variation of tool rotation used were 1100 and 2200 rpm and surface roughness of 0.32; 1.25; and 1.88 μm initially obtained from different surface modification methods. The shear test was conducted at FLW dissimilar joint based on AWS D8.9-97 standard. The results showed that the shear stress increased along with the higher tool rotation and at the greater surface roughness. The highest shear strength value was found at the tool rotation of 2200 rpm and surface roughness of 1.88 μm with 9.447 MPa. The tool rotation may produce a higher heat input as well as an effect on the value of nylon hardness. On the other hand, rougher SS surfaces provide a larger area for the interfacial adhesive bond between nylon and metal; therefore, they can act as an interlocking site when the shear loading was applied. These phenomena were also confirmed by fracture morphology and microscopic image analysis.

Abstract: Efficiency energy is an importance goal in transportation device development. Reducing weight of device is a way to reduce fuel consumption from transportation device, using thin plat in a device or construction could reduce the weight. The originality of this study was Micro Dissimilar Friction Stir Spot welding used to join Cu and Al plate with copper sheet on top the aluminum sheet. Micro welding is a joining thin plat less than 1 mm welded by Friction Stir Spot welding which has been called a Micro Friction Stir Spot welding, using a Pin on the Shoulder. Peak load average, macrostructure and shear strength of a copper and aluminum sheet joint welded by Micro Friction Stir Spot welding were discussed in this study. Copper and Aluminum 0.5 mm could be successfully joined. Shoulder diameter 6 mm effected to the highest peak load, and welding force 50 kgf significantly increased the peak load. Mixing Cu and Al formed in a weld joint. Friction was not complete occurred in shoulder interface and deflection copper sheet formed in around weld nugget because of Pin and Shoulder. A Pin on Shoulder affect to form a joint only around Pin, shear strength could not conclude because the weld joint areas developing tend to an incomplete joining.

Abstract: This work presents a comparative study of the mechanical properties of resistance spot welded joints (RSW). RSW is widely used in sheet joining. Hence, the mechanical properties and their strength are presented. The main parameter is the welding current that has a big role on the heat generation and joint strength. The strength improvement due to the current increasing is regular and more effective than the weld time and the electrode pressure. Stainless steel has good weldability in sheet form. Galvanized steel, aluminum and carbon steel have been widely spot-welded. Moreover, dissimilar materials are also spot weldable where the two sheets of different metals can be joined. For the same sheet thickness at 1 mm, it was shown the shear strength of mild steel 3.8 KN, while for aluminum 1.4 KN this mean the shear strength of mild steel higher than aluminum. For the same metals, the increasing of the thickness will increase the strength. This is due to the weld area increasing. All the values were taken at the pull-out fracture condition. Hence, the suitable weld area at the welding condition was assumed. Fatigue strength for some metals has been presented. Fatigue strength of MS1300 is higher than those of steel DQSK, and steel DP800 at the for 1.6 mm thickness and stress ratio, R= 0.1. Because of the thickness, it has a minor effect on the fatigue properties of spot welded joints.

Abstract: The study of the shear strength parameters of mixtures comprising tire-derived aggregates (TDA) and clay was the main objective of this experimental work. The tests were performed using the direct shear box. First, the test was performed on specimens comprising only clay in its natural state and then on mixtures consisting of clay and TDA in increasing contents. A total of four samples (natural clay and natural clay with 2, 4, and 6% tire-derived aggregates)) were made and tested at three normal stress levels (100, 200, and 300 kPa). Then, Mohr-Coulomb failure envelopes were drawn to determine the internal friction angle and cohesion for all mixes. The results were compared to find the optimum TDA content and to study the stress-strain behavior of the mixtures. It was observed that mixing TDA up to 6% by weight with clay significantly changes the shear strength, and the internal friction angle increases from 27.47 to 59.39º (an increase of 46.25%). However, the cohesion significantly decreases from 45 to 26 kPa (a decrease of 57.77%). On the other hand, it was observed that increasing the TDA content reduces the density and increases the shear strength of the mixtures. Also, the addition of TDA increases the mixture consolidation and deformation level at failure.

Abstract: Kenaf fiber-reinforced beech plywood was evaluated with 5variantmanufacturing adhesive methods in order to increase its acceptance in the wider industrial use. We aimed in enhancing the mechanical characteristics of beech wood kenaf fiber-reinforced using epoxy resin, Urea-formaldehyde, Melamine urea-formaldehyde, isocyanate MDI prepolymer and polyurethane and exhibited diverse effects. Tensile strength, Modulus of Elasticity, Modulus of Rupture, Shear Strength and Screw withdrawal resistance were enhanced by urea formaldehyde, while tensile strength was decreased by Urea Formaldehyde, Melamine Urea-Formaldehyde and isocyanate prepolymer. Epoxy resin, on the other hand, is well suited for kenaf fibre reinforcing. For example, polyurethane reduced the mechanical characteristics of kenaf fibre reinforced beech wood. Shear strength, Modulus of Elasticity and Modulus of Rupture were all superior than glass fibre reinforced epoxy resin bound beech wood.