基于时变疲劳特性的悬臂式掘进机关键结构工作可靠性研究

Domestic research on the working reliability of the cantilever road-header is deficient in some aspects such as the load spectrum being incompatible with the actual geological and working conditions, being weak in presenting time-varying behavior of the fatigue resistance of the structures on the machine, as well as being short in numerically expression of the damage that caused by dynamic response like vibration of the structures. As for that, this project is proposed to cover the aforementioned deficiencies in some degree by applying the working parameters and vibrations of the working road-header under shaft coal mining. Firstly, the load files would be built according to real measurements and its impacts on the anti-fatigue property of the material is also considered in necessary. Thus the strength reduction model is built with time and load varying involved and used in the stress-strength interference model, which is applied in working reliability estimation for the critical structures. Secondly, the working modal parameters of the key structures are studied, form which and with the help of damage locating index analysis by finite element simulation, the nonlinear mapping between modal parameters and structure damages would be built and used to identify or predict possible structure damages. Lastly, the damage status of the structure is formulated according to real measurements and is applied to renew the strength reduction of the structure iteratively. Thereby, both dynamic response and time-varying strength are considered to assess the working reliability of the structures on the road-header and with higher accuracy. This would strongly support the development of research on working reliability of huge equipment that used in domestic mining industry.

针对现阶段我国悬臂式掘进机工作可靠性研究过程中存在的截割头载荷谱不完全符合实际地质和工况条件、关键结构疲劳可靠性时变特征反映不足、振动和冲击对系统结构稳定性破坏程度表征不清晰等问题，开展基于时变疲劳特性的悬臂式掘进机关键结构工作可靠性研究。以井下实测的掘进机工作参数和关键结构振动响应为基础，首先，结合不同工况下动力参数与截割臂位姿受力分析编制截割头载荷谱，构造反映动态载荷影响的强度-时间退化模型，研究基于应力-强度干涉模型的结构抗疲劳可靠度；其次，综合损伤敏感指标，构造结构模态参数与损伤度的非线性映射关系，研究结构损伤的实时识别和参数化表征；再次，基于实测数据，结合工作载荷和动态响应对结构抗疲劳特性的影响，迭代修正结构剩余强度，完成结构抗疲劳可靠度估计与失效验证。项目研究有效提高悬臂式掘进机工作疲劳可靠度准确性，为我国特有复杂地质环境下大型设备结构疲劳可靠性分析提供理论和实践基础。

围绕“将掘进机动态载荷特点、结构疲劳特性的时变性、结构工作模态参数变化联合起来综合开展工作掘进机时变可靠性研究”这一总体研究内容及目标，完成了基于实测工况数据的掘进机动态载荷谱编制；分析了关键结构在高强度高频率载荷下的应力响应规律；编制动态载荷体现了时变性,为解决复杂工况下悬臂式掘进机结构时变可靠性评估提供了载荷依据。.其次，以井下实测的设备振动信号为基础，一方面全面统计信号的时频域特性，另一方面通过论证和试验多种现代信号分析手段完成了对结构模态在不同工况、不同时段的动态监测，构建了基于结构振动特性的动态损伤识别模式，将掘进机的工作振动监测转化为模态参数的时变特性表征；在结构损伤和异常判别中，引入机器学习算法、自适应学习算法，将模态参数如频率、振型、能量的变化进行了统计和分类自学习，实现了损伤的智能界定，验证了动态、智能化定性结构损伤的可行性，建立了一套基于智能学习的结构损伤定性判断方法。结合现场结构损伤的实际情况，为损伤定量分析如分级预警提供可行方案。 .最后，基于“将结构可靠性与功能可靠性相结合”这一专家建议，提出以高效掘进、动力优化为目标，从掘进调度的角度，以高效控制为手段，进行了考虑误差的井下掘进机行进纠偏调度控制研究，从行进调度优化控制的角度提升了掘进机工作可靠度，促进保障掘进效率。.面对煤炭行业矿井作业智能化升级的工业需求，所研究内容在设备健康状态监测与评估方面的成果对于掘进机远程智能监控系统的集成和实现具有较高的工程应用潜质和价值。基于研究过程所提炼的模态特征提取技术结合基于聚类分析与深度置信网络的时间累积加权控制技术在基于大数据监测的设备健康诊断方面具有显著的延续性及可延展性。