预应力钢绞线专用拉伸夹具的优化设计

钢绞线拉伸试验机的传统V形夹钳与钢绞线外形结构不匹配,使钢绞线受力不均,极易出现试样在夹具内或在夹具附近断裂,导致试验数据失真。对试验机钳口进行优化设计,将钳口由V形改成半圆形后,增加了夹具与钢绞线的夹持面积,提高了夹齿与钢绞线之间的握裹力。拉伸试验结果表明:半圆形夹钳与V形夹钳相比,试样断钳口比例由64%降到16%,打滑比例由22%降为0,保证了试验数据的准确。

Optimization design of special tensile clamp for pre-stressed strand

The reason that traditional V-type clamp of tensile testing machine for steel strand did not match with the shape of steel strand caused steel strand uneven force loading, specimen cracking in clamp or near the clamp occurred easily, which made test data distortion. The testing machine clamp was optimized design, the clamp was changed from V-type into half-round, the holding area between clamp and steel strand was increased, the gripping force between clamp tooth with steel strand was raised. Tensile testing results showed： to compare half-round clamp with V-type clamp, the proportion of specimen cracking in jaw decreased from 64% to 16% , the proportion of specimen slipping from 22% to zero, the accuracy of testing data were guaranteed.