Peel Tensile Strength Research Articles

Effect of strength of steel sheets on peel tensile strength and failure mode of dissimilar joint of spot welds

Advanced high strength steel sheet (AHSS) is widely used in the automotive body for weight reduction and the improvement of crash performance. Peel tensile strength of spot welds tends to decrease as the steel sheet strength increases. Therefore, in order to further expand the application of AHSS, technology to prevent fracture of spot welds is required. In order to achieve that, it is necessary to understand the characteristics of spot-welded joints and clarify the controlling factors. However, most of the conventional joint strength evaluations have been conducted on the same kind material joints, and there are few systematic studies on the joint strength and fracture mode of dissimilar material joints that are often used in actual vehicles. Therefore, the purpose of this study is to obtain a guideline for grasping the characteristics of dissimilar joints in case of the plug failure. Using various joint shapes, we compared the peel tensile strength and failure position of the same kind material joints and the dissimilar material joints with the TS1500 MPa class hot-stamped steel sheet. As a result, it was found that the deformation behaviour of the test piece affects the joint strength and fracture position of the dissimilar material joints. Specifically, in dissimilar material joints, cross tension joints and double cup-shape tension joints tended to break on the TS1500 MPa class hot-stamped steel side. On the other hand, L-shape tension joints broke on the lower strength material side. From these results, it is considered important to understand their deformation behaviour in order to analyse and predict the fracture phenomenon of spot welds in actual vehicles and automotive parts.

Effect of hardness on the mechanical properties of kiwifruit peel and flesh

ABSTRACT The mechanical properties of kiwifruit serve as the foundation for mechanical damage. In this work, the effect of hardness on the mechanical properties of kiwifruit was explored, and a hardness-mechanical property prediction model was developed. The results in this study showed that the tensile strength of the kiwifruit peel increased with decreasing hardness by 0.51, 0.75, 0.83, and 1.02 MPa in the axial direction and 0.48, 0.68, 0.92, and 1.08 MPa in the radial direction, respectively. While the peel’s elastic modulus decreased by 21.15, 14.03, 11.87, and 10.52 MPa in the axial direction and 15.04, 10.68, 8.45, and 7.54 MPa in the radial direction. At the same ripening stage, peel tensile strength did not differ significantly (P > .05), whereas peel modulus of elasticity was greater in the axial direction than in the radial direction. The results of the flesh compression test showed that the compressive strength of the flesh decreased with decreasing hardness to 0.36, 0.25, 0.09, and 0.06 MPa in the axial direction and 0.36, 0.23, 0.11, and 0.06 MPa in the radial direction, respectively. The modulus of elasticity also decreased to 1.05, 0.82, 0.42, and 0.32 MPa in the axial direction and 0.26, 0.45, 0.80, and 1.15 MPa in the radial direction, respectively. The compressive strength and modulus of elasticity of kiwifruit flesh did not differ significantly in the axial and radial directions at the same stage of ripening (P > .05). The model’s accuracy is demonstrated by correlation coefficients of tensile strength (compressive strength) and elastic modulus of kiwifruit peel and pulp in axial and radial directions, which were 0.97, 0.99 (0.99, 0.99), and 0.93, 0.90 (0.96, 0.99), respectively, for anticipating the mechanical characteristics of peel and flesh. It can provide theoretical and data references for post-harvest kiwifruit to reduce the mechanical damage.

異強度板組の抵抗スポット溶接継手の剥離強度と破断位置に及ぼす材料強度の影響

異強度板組の抵抗スポット溶接継手の剥離強度と破断位置に及ぼす材料強度の影響

Effect of overlap support characteristics on peel strength of weld-bonded joints

Bonded joints normally have a low peel tensile strength, since the stresses are concentrated on the small bond line. It has been proposed that adding a weld-bonded overlap support to the T-peel joint will enhance its peel strength tremendously. Since this support may increase the weight of the joint, a trade-off between weight increase (material type and thickness) and improved peel strength must be made. The aim of the present work is to investigate the effect of the overlap support characteristics (material and thickness) on the stress distribution of the T-peel joint. Different materials with different thicknesses are considered in order to strengthen the T-peel joint. A finite element technique was used for evaluating the current models. The results showed that the peak stress decreases with increasing thickness and stiffness of the overlap support.