双孔微剪切法测定材料的局部强度

工程上进行焊接接头强度设计或承载能力评定时,需要测定焊接接头各区域的局部强度.文章提出一种双孔微剪切局部强度试验测定方法.在被测材料的小区域两侧开2个小孔,剪切压头从其中一孔对被测区域加载直到破坏,根据加载过程中的载荷位移曲线,确定材料的强度.实验说明,该方法具有很好的重复精度.通过对管线钢、紫铜和6063铝合金三种材料的标准拉伸和双孔微剪切的对比试验,发现拉伸屈服强度是屈服剪应力的2.01倍,抗拉强度是最大剪应力的1.46倍.最后测定了焊接接头局部强度,其分布趋势与硬度值基本相似.

Test for local strength of materials with double-holes micro-shearing method

The test for local strength of welded joints is necessary for strength design and load capacity estimation of the welded joints.A double-hole microshearing method was presented to estimate the local strength of the welded joint.Two small holes were drilled around the area of the welded joint to be tested.A shear indenter was then inserted into one hole and loaded until fracture of the material.Local strength of material could be determined in terms of the load-displacement dependence during the loading process.Experimental result verified that there was a good repeatability of this test.By means of comparison between the results of standard tensile test and doublehole microshearing test for welded joints of pipeline steel,copper,and 6063 aluminum alloy,it was found that the ratio of the tensile yield strength to yield shear stress was 2.01,and the ratio of tensile strength to ultimate shear stress was 1.46.Finally,the local strength of the welded joint was tested,and its distribution along the joint exhibited the tendency similar to that of the hardness.