高强铝合金螺栓球节点轴向受力性能试验研究

Experimental Research on Mechanical Properties of High-Strength Aluminum Alloy Bolt Ball Joints Under Axial Tension and Compression

为研究复合材料空间桁架结构用铝合金螺栓球节点的轴向受力性能,开展了使用高强不锈钢螺栓和高强铝合金螺栓的铝合金球节点拉伸与压缩试验。针对不同螺栓材质、不同封板及套筒尺寸的铝合金螺栓球节点试件,分别开展了节点轴向拉伸和压缩试验,获得了不同节点尺寸参数情况下铝合金螺栓球节点的轴向拉压承载响应规律及破坏模式。试验结果表明:S51740高强不锈钢在弹性模量、强度及延性方面均优于7075-T6高强铝合金;因螺栓材质和封板厚度不同,铝合金螺栓球节点在拉伸荷载作用下发生螺栓拉断破坏、封板剪切破坏及球内螺纹剪切破坏,选用高强不锈钢且增加封板厚度能显著提高节点初始刚度;因套筒大小和封板厚度不同,铝合金螺栓球节点在压缩荷载作用下发生套筒压缩破坏和封板剪切破坏,套筒承压面积是节点承压设计的主要控制参数;当铝合金螺栓球节点部件进入塑性后,节点拉伸刚度和压缩刚度均显著降低。

To study the mechanical properties of aluminum alloy bolt ball joint used in composite space truss structures under axial compression,tensile and compression tests of aluminum alloy ball joints with high-strength stainless steel bolts and high-strength aluminum alloy bolts were conducted.Axial tensile and compression tests were carried out respectively for aluminum alloy bolt ball joints with different bolt materials,sealing plates and sleeve sizes,and the axial tensile-compression bearing response laws and failure modes of aluminum alloy bolt ball joints with different joint size parameters were obtained.The test results showed that S51740 high-strength stainless steel was superior to 7075-T6 high-strength aluminum alloy in terms of elastic modulus,strength and ductility;due to the difference of bolt material and thickness of sealing plate,the aluminum alloy bolt ball joint would occur bolt fracture failure,sealing plate shear failure and ball internal thread shear failure under tensile load,and the selection of high-strength stainless steel and increasing the thickness of sealing plate could significantly improve the initial stiffness of joints;due to the different sizes of the sleeve and thickness of the sealing plate,the aluminum alloy bolt ball joint would occur sleeve compression failure and sealing plate shear failure,and the bearing area of sleeve was the main control parameter of the joint bearing design;when the aluminum alloy bolt ball joint parts entered into plasticity,the tensile stiffness and compression stiffness of the joint were significantly reduced.