基于伽马过程的钢桥构件疲劳裂纹检测维护策略优化

Optimal Inspection and Maintenance Strategy for Fatigue Cracks of Steel Bridge Members Using Gamma Process Model

针对钢桥构件疲劳裂纹问题,研究了基于伽马过程的疲劳裂纹增长过程模拟和疲劳失效概率;分析了检测概率和维护措施对钢桥构件疲劳使用寿命的影响以及钢桥构件疲劳裂纹全寿命周期检测维护成本;以最大化检测维护后疲劳使用寿命和最小化疲劳裂纹检测维护总成本为多目标优化函数,建立了基于伽马过程和遗传算法的钢桥构件疲劳裂纹检测和维护策略优化计算模型;最后对某钢桥桥面板加劲肋疲劳裂纹进行了优化分析。结果表明:检测维护成本随疲劳使用寿命期望值的增加而增加;对比1次检测维护策略,采用2次检测维护策略可在小幅增加检测维护成本的基础上大幅延长疲劳使用寿命;Pareto优化解集可提供多种不同检测维护成本和疲劳使用寿命要求的检测维护优化策略。

Aimed at the fatigue crack problems of the steel bridge members,some aspects were investigated which included the propagation simulation of fatigue cracks based on the Gamma process（GP）,the GP-based fatigue failure probability.In addition,the effects of the probability of damage inspection and maintenance measures on the fatigue service life and the life-cycle cost for the damage inspection and maintenance on the fatigue cracks of the steel bridge members were also analyzed.Taking the maximization of the fatigue service life after inspection and maintenance and the minimization of the life-cycle cost of inspection and maintenance for fatigue crack as the multi-objective functions,the calculation model based on the GP and genetic algorithm（GA）was established to optimize the inspection and maintenance strategy for the fatigue cracks of steel bridge members.Finally,an example of the fatigue cracks of the stiffing slab in a steel bridge deck was analyzed by the optimal model.The results show that the inspection and maintenance cost increases with the increase of expected fatigue service life.Compared with the one timeinspection and maintenance strategy,the expected fatigue service life will be largely extended in the condition of small increase on the inspection and maintenance cost if the strategy of two times inspection and maintenance has been adopted.The optimal Pareto solutions can provide optimal strategies for inspection and maintenance required by the desired fatigue service life and different inspection and maintenance costs.