多环境场耦合下无砟轨道灌缝胶粘附耐久性及其跨尺度失效机理

Based on the lack of in-depth understanding of sealant failure mechanism in environmental conditions, which lead to the lack of existing durability evaluation test method can not predict the field performance of sealant accurately in actual service conditions, and also, this project aims at studying sealant adhesion durability and its cross-scale failure mechanism. First, based on the analysis of the excitation response of ballastless track structure, the force mode and failure evaluation threshold of sealant are studied, and the main environmental conditions and acceleration effect of parameters are studied based on literature review and accelerated testing theory. Second, based on the macroscopic DT loading test method and AFM nano-indentation and other characterization methods of microcosmic properties of sealants, the developing rules of macro/micro indicators in various environmental conditions are studied respectively. Lastly, based on the genetic algorithm and Copula function model, the cross-scale correlation of interaction behavior of sealant in actual environmental conditions are researched, and then the failure mechanism is explained; based on logistic regression and deep neural network theory, the contribution weights of various environmental fields onadhesion failure of sealant are studied, and the correlation model of adhesion behavior across environmental field excitation is established. The durability evaluation method of sealant under the coupling of multiple environmental fields is proposed to provide theoretical reference on improving micro-structure design for sealants.

基于目前对环境因素下无砟轨道灌缝胶粘附失效机理缺乏深入认知，以致相应灌缝胶粘附耐久性评价方法难以准确预测其服役特性的现状。本项目拟针对多环境场耦合下灌缝胶粘附耐久性及其跨尺度失效机理展开研究。首先，基于无砟轨道结构激励响应分析灌缝胶受力模式及失效判定阈值，基于加速加载试验研究灌缝胶主要服役环境场及环境场加速参数效应。其次，基于宏观DT加载及AFM纳米刻痕等材料微观属性表征手段，研究不同环境场强度下灌缝胶粘附特性宏/微观指标演变规律。最后，基于遗传算法及Copula函数模型，研究环境场作用下灌缝胶粘附交互行为跨尺度关联性，阐释灌缝胶粘附特性失效机制；基于逻辑回归及深度神经网络算法，研究不同环境场对灌缝胶粘附性失效的贡献权重，构建灌缝胶粘附行为跨环境场激励等效响应关联性模型，并据此提出多环境场耦合下灌缝胶粘附耐久性评价方法，为针对性改善灌缝胶微观结构设计提供理论参考。

基于目前对环境因素下无砟轨道灌缝胶粘附失效机理缺乏深入认知，以致相应灌缝胶粘附耐久性评价方法难以准确预测其服役特性的现状。本项目针对多环境场耦合下灌缝胶粘附耐久性及其跨尺度失效机理展开研究，基于无砟轨道结构激励响应分析灌缝胶受力模式及失效判定阈值，确定了紫外老化、水解、剪切振动是引发灌缝胶长期性能衰减的主要环境因素形式，并确定了不同环境工况参数，基于灌缝胶工况分析及自主开发的灌缝胶低温性能测定仪（LTTT），开发了评价灌缝胶粘附性能试验方法。借助AFM的PeakForce QNM模式观测灌缝胶范德华力及表面粗糙度，并探索适用于灌缝胶观测接触力（Tapping Force）及相关观测参数，同时开发可满足AFM纳米级扫描范围的灌缝胶微观属性观测试件；借助XPS分析灌缝胶与底座板缝壁间化学成键特性，为避免缝壁化学成分干扰，拟分别选用缝壁代表性材料（SiO2及CaCO3颗粒）与灌缝胶混合物分析化学成键特性，研究不同环境场强度下灌缝胶粘附特性宏/微观指标演变规律。最后，开展灌缝胶在紫外老化、水解、剪切振动作用下粘附性能衰变规律研究，以及宏观-微观作用下灌缝胶在多环境耦合作用下性能的关联性分析，研究了灌缝胶粘附交互行为跨尺度关联性，阐释了灌缝胶粘附特性失效机制，并据此提出多环境场耦合下灌缝胶粘附耐久性评价方法，为针对性改善灌缝胶微观结构设计提供理论参考。