焊接残余应力场声弹性不稳定性分析
Instable acoustic elasticity phenomenon in welding residual stress field
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摘要: 基于声弹性效应,超声波可以无损检测出结构内部应力.超声波法焊接残余应力测量克服了传统应力测量方法费时耗力、破坏、体积庞大等缺点,对多种焊接结构残余应力进行的测量已证明其准确和可靠.在残余应力场测量时发现了在低应力弹性区存在声弹性不稳定现象,利用声弹性模拟试验对声弹性不稳定现象进行了分析研究.根据焊接残余应力场弹性区临界折射纵波包络波峰声弹性效应随机分布呈双峰分布的试验现象,提出了弹性区声弹性主应力计算公式,可通过超声波法纵向残余应力测量结果计算出测量点的两个主应力及横向残余应力.Abstract: Aiming at the path planning problem of synchronous dual-robot welding process of the hand pallet truck frame main, the multiple traveling salesman problem(MTSP) was transformed into a traveling salesman problem(TSP) by introducing virtual points, and weld lines were encoded by transposition express. An artificial bee colony(ABC) algorithm was adopt to build a mathematical model of dual-robot synchronous welding based on a state transfer strategy, and an approximate solution of global optimal welding path was calculated by simulation. Then a simulation experiment with ABC algorithm was conducted and compared with the improved adaptive genetic algorithm and artificial fish swarm algorithm. The result shows that the ABC algorithm has a faster convergence speed. It possesses an essence of good repeatability, and can obtain a shorter welding time. The dual-robot path planning method based on ABC algorithm can deal with dual-robot simultaneous welding problem of the pallet truck frame effectively.
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Keywords:
- instable acoustic elasticity /
- ultrasonic method /
- residual stress
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