基于ANSYS的带切口半圆弯曲试验参数分析

Parameter Analysis of Semi-circular Bending Test on Notched Specimen Based on ANSYS

采用带切口的试件进行半圆弯曲试验(SCB)可以更好地评价存在反射裂缝的沥青路面的抗裂性能。为了明确试件厚度、切口宽度、切口深度、支座间距等试验参数对带切口SCB试件力学响应的影响,采用ANSYS建立三维有限元模型对SCB试验进行数值模拟。计算结果表明:当试件厚度大于50 mm时,底部拉应力趋于定值,而试件厚度太薄会导致应力集中,因此试件厚度选择为50 mm;切口处底部拉应力随着切口宽度的增加逐渐减少,基本上成线性关系,为了便于观察试验现象并考虑到切缝切割工艺,切口宽度确定为1.5 mm;切口处底部拉应力随着切口深度的增加逐渐增大,为了选择适宜的切口深度,尚需对15、20、25 mm切口深度进行试验验证;支座间距选择为试件直径的0.8倍,此时切口底部拉应力值最大。

It is preferable to carry out Semi-circular Bending （SCB） Test on notched specimens to evaluate anti-cracking performance of asphalt pavement with reflecting cracks. In order to specify influence of test parameters such as thickness of specimen, width and depth of notch and distance of supporting points on the mechanical response of the notched specimens, the 3D models were set up by using ANSYS to simulate SCB test. The analysis results show that （ 1 ） when the thickness of specimen was greater than 50 mm, tensile stress at the bottom of the notch remained constant, in consideration of stress concentration owing to thin specimen, the 50 mm thickness of specimen would be appropriate ; （2） the tensile stress at the bottom of the notch was linear decreased with the increasing of the width of notch, in view of experiment observation and cutting technology, 1.5 mm in width of notch would be better; （ 3 ） the tensile stress at the bottom of the notch increased with the increasing of the depth of notch, showing a linear relation between them basically, and it is required to verify the specimens with 15 mm, 20 mm and 25 mm depths of notch by next experiment to search appropriate depth of notch; （4） the distance of supporting points was 0. 8 times of diameter of specimen, the tensile stress at the bottom of the notch reached peak at this time.