摘要：通常情况下金属材料在交变载荷的影响下，会在某一区域造成材料的累积损伤，受到一定程度的交变载荷之后材料表面会突然出现裂纹或者突然发生整体断裂，这个过程被称作金属的疲劳效应。磁记忆检测方法属于无损检测中比较新颖的方式之一，它可以对金属构件进行损伤的早期诊断。本文将磁记忆检测方法在金属疲劳损伤评价及其疲劳寿命的评估分析领域中进行了应用，通过对我国CRH3型高速动车组轮对材料25CrMo4合金钢进行常温裂纹扩展率试验，检测并记录载荷相同且应力循环次数不同时的磁信号强度变化情况，分析讨论磁信号变化与25CrMo4合金钢的疲劳寿命以及试件断裂裂纹长度之间的联系，以此为基础建立以磁记忆信号为主的早期疲劳损伤评估模型。经过试验确定了载荷循环次数对于材料内部磁信号的影响程度并验证了磁记忆检测技术对于应力集中区域的探测能力，在试验完成后应用ANSYS 15.0版本有限元仿真软件分别对试验材料所受到的载荷数值和负载情况下的疲劳程度进行了仿真模拟分析。43667

毕业论文关键词：金属疲劳；磁记忆检测；25CrMo4合金钢；疲劳试验

Magnetic Memory Testing Fatigue Evaluation Research

Abstract: Usually metallic materials under the influence of alternating load, will cause the cumulative damage of material, in an area under a certain degree of alternating load after suddenly appeared on the surface of cracks or sudden integral fracture, this process is called metal fatigue effect.Magnetic memory testing method belongs to the nondestructive testing is new in one way, it can be used to the early diagnosis of the damage of metal component, in this paper, the magnetic memory testing method in the metal fatigue damage evaluation and fatigue life evaluation was carried out in the field of application, through to our country CRH3 type high speed emu wheels for 25 crmo4 steel alloy materials for room temperature crack propagation rate test, detect and record the same load and stress cycle number different magnetic signal intensity change, analyzed and discussed the magnetic signal changes and 25 crmo4 steel alloy and the fatigue life of the connection between the specimen fracture crack length, by building is given priority to with magnetic memory signal early fatigue damage assessment model.After test to determine the load cycles for magnetic signals inside the material and verify the influence of the magnetic memory testing technique for the determination of stress concentration zone detecting ability, at last, ANSYS finite element software version 15.0 respectively to test materials by fatigue load size and load conditions for simulation analysis.

Key words:Metal fatigue;Magnetic memory testing;25 crmo4 alloy steel;Fatigue test

 目录

1 绪论 1

1.1 课题的目的和意义 1

1.2 国内外研究现状与水平 1

1.2.1 国内 1

1.2.2 国外 2

1.3 发展趋势 2

1.4 本课题研究的主要内容和意义 2

2 磁记忆检测技术简述以及金属疲劳研究背景 4

2.1 金属磁记忆检测技术简述 4

2.1.1 金属磁记忆检测技术基本原理和特点 4

2.1.2 金属磁记忆检测技术的发展 4

2.2 金属疲劳 5

2.2.1 金属疲劳简介 5

2.2.2 各国轮对疲劳试验背景