运载火箭大直径螺栓承受拉弯耦合载荷失效判据研究

随着中国运载火箭箭体直径和载荷不断增大,在关键承力点,逐渐使用大直径螺栓,由强度高塑性好的材料制造.因为力学环境复杂,受拉螺栓会承受较大附加弯矩,导致提前破坏.为了准确评估螺栓塑性下附加弯矩折合轴拉力,从梁理论出发,推导了附加弯矩折合轴拉力的塑性折减系数,并进行仿真验证.然后从使用场景出发,设计了一套能够复现螺栓承受拉...

Research on the Failure Criterion of Large Diameter Bolt of Launch Vehicle Subjected to Tensile and Bending Coupled Loads

With the continuous increase of the diameter and load of our launch vehicle,large-diameter bolts are gradually used at key bearing points,which are made of materials with high strength and good plasticity.Due to the complex mechanical environment,tension bolts could bear a large additional bending moment,leading to premature failure.In order to accurately evaluate the additional bending moment-reduced tensile force of the bolt under plasticity,the plastic reduction coefficient of additional bending-reduced axial tension based on beam theory and performs simulation verification is deduced.Then,starting from the application scenario,a set of test fixture is designed to produce the tension and bending load of the bolt,and the failure test of the large diameter bolt is carried out.After obtaining the test results,by calculating the recurrence test,extract the tensile force and additional bending moment that the bolt bears when it fails,and use the reduction factor obtained above to calculate the total shaft tensile force.The value differs from the factory failure average value by about 1%,thus verifying correctness of the method.