【作者】 易当祥；

【导师】 吕国志；

【作者基本信息】 西北工业大学 ， 固体力学， 2005， 博士

【摘要】 自行火炮行动系统疲劳寿命预测与可靠性仿真方法的研究，为自行火炮的维修保障提供了理论依据和参考价值，完善和提高武器装备的保障力和生存力，具有重要的意义。本文建立了一套随机载荷作用下行动系统疲劳断裂寿命可靠性分析的CAE仿真方法。在自行火炮虚拟样机仿真获得行动系统关重件随机载荷时间历程的基础上，以扭力轴为主要研究对象，疲劳断裂可靠性理论为基础，考虑各种随机因素的分散性，从安全寿命／损伤容限分析的角度，全面深入地研究了行动系统关重件在多行驶工况随机载荷作用下裂纹萌生可靠寿命及裂纹扩展可靠寿命计算理论和仿真方法。 建立基于ATV的自行火炮虚拟样机、数字的等级路面以及虚拟样机与路面之间的接触模型组成的虚拟行驶试验系统，仿真并获得行动系统关重件在各级标准路面和不同档位时的随机载荷时间历程。通过改进的三峰谷计数、参数估计和权系数法，获得了各工况合成后的联合概率密度函数。并提出了概率密度——最速下降法来扩展多工况下的二维疲劳载荷，编制了8×8的全寿命里程载荷设计谱。 提出了构件疲劳可靠性试验仿真并拟合获得构件P-S_a-S_m-N曲面的方法。考虑了构件的重要几何尺寸、应力集中系数K_f、尺寸修正系数ε和表面加工修正系数β等横向因素的随机性对疲劳寿命的影响。对于扭力轴相关重要几何尺寸的分散性影响，运用了改进的进化神经网络(MENN)进行模拟。通过MSC.Marc参数建模计算而获得的扭力轴危险部位的最大剪应力作为MENN训练样本，研究和运用了独特的编码技术和先进的遗传操作算子和进化策略，得到了用遗传算法优化后的神经网络结构及其权值和闽值矩阵。仿真结果检验表明MENN具有很好的精度、拟合能力和泛化能力。然后以材料P-S_a-S_m-N曲面为基础，由应力寿命法和Monte-Carlo法仿真并获得了扭力轴在各恒幅载荷作用下给定可靠度的疲劳寿命，由此拟合得到了扭力轴的P-S_a-S_m-N曲面。与实验结果比较，表明该疲劳可靠性试验仿真方法是合理的。 考虑了扭力轴的两类不同性质的横向随机性和纵向随机性的影响，由MM法则和EM法则修正二维概率Miner准则，推导获得了MTPMiner准则和ETPMiner准则，运用了应力寿命—MTPMiner准则理论和应力寿命—ETPMiner准则理论分别进行了扭力轴的疲劳可靠性分析，提供了某个可靠度下扭力轴疲劳寿命的变化区间。并从疲劳安全寿命的角度，根据疲劳寿命的仿真结果提出了完善自行火炮扭力轴的大小修周期的建议。而且，运用上面的计算理论和仿真方法，仿真了行动系统履带销、履带板和主动轮等关重件的疲劳可靠寿命。同时开发了自行火炮行动系统疲劳可靠性仿真软件，该软件解决了VC与MATLAB之间数据多交互多更多还原

【Abstract】 Fatigue lives prediction and reliability simulation of the driving system of a certain type of self-propelled gun are studied. This dissertation has provided these theoretic foundation and technical references for the maintenance guarantee of self-propelled guns. It is beneficial to improve guarantee capability and survivability of weapon equipments. A new set of CAE simulative method about fatigue fracture reliability analysis has been established. The random loading acting on the key components of the driving system have been obtained by simulating the virtual prototype of the self-propelled gun on various types of standard road. The scatters of all kinds of random factors are investigated based on fatigue fracture reliability theoretics. Furthermore, these calculation theoretics and simulation methods for crack initiation lives and crack propagation lives of the torsion shaft have been studied deeply from fatigue safe life/damage tolerance’s view under multi-driving condition stochastic load.Firstly, the virtual driving experiment systems are built, which consist of the self-propelled gun virtual prototype using ATV (ADAMS/Tracked Vehicle), the numerical standard road surfaces and the contact models between the virtual prototype and the road surfaces. And the stochastic loading history of the key components of the driving system is simulated and obtained when the self-propelled gun drives in different speed grades on various types of standard road surfaces. The random loading has been counted, dealt with in statistics methods, synthesized and extended with these theories and methods, Which include the advanced rain-flow counting method, the weight coefficient method and the probability density — the steepest descent method. As a result, the 8 X 8 two-dimensional load design spectrum for the whole life was fulfilled.Secondly, this thesis has presented a fatigue reliability test simulation method of the structural detail to obtain the P-Sa-Sm-N fatigue surface. The random of these fatigue transverse factors has been considered, such as these correlative important sizes of the key components, the stress concentration factor K_f, the size correction factor ε and the surface quality correction factors β ,and so on. The effect of the scatter character of some critical sizes of the torsion shaft is investigated using the MENN (Modified Evolutionary Neural Network). The maximum shearing stress history of the critical location on the root of spline tooth obtained from results of simulation by MSC.Marc software is used for the MENN training samples. And the weight matrix and biases matrix of Neural Network is optimized and given by Genetic Algorithm simulation更多还原