空间网格结构杆件长度制作偏差测量试验研究

Length deviation tests on structural members of space latticed structures

空间网格结构属于高次超静定结构,对几何初始缺陷较为敏感,网格尺寸制作偏差引起的安装应力对结构承载力性能的影响不容忽视.通过试验实测325组螺栓球样本的削面中心距偏差与376组弦杆样本、343组腹杆样本的杆件长度偏差,采用概率统计和假设检验方法,获得所有偏差基本概率分布与统计参数.基于得出的统计参数,引入多个制作偏差样本,折算成等效温差并计算由此产生的初始应力和初始变形,采用非线性有限元方法对试验模型进行了全过程受力分析.有限元结果与试验测得的极限承载力吻合良好.

The sensitivity to initial geometric imperfection of space latticed structures may be attributed to the nature of high-order statically indeterminate structures.Thus random manufacturing deviation,which may exert negative impacts on the load-carrying capacity,should be experimentally studied.Measurement of 376 chord members,343 web members and 325 bolt spheres were carried out.Based upon the obtained datum,probabilistic distribution and statistical parameters were determined.The manufacturing deviation was converted into equivalent temperature difference by introducing several random samples.Nonlinear numerical simulation by incorporating initial stress and initial deformation were conducted,and the satisfactory predictions of load-carrying capacity were achieved.