苏艳,钟勇,苏虹,王成章,吴帅.自然环境-疲劳交替作用对2024典型连接结构累积损伤的影响研究[J].表面技术,2020,49(10):268-275.
SU Yan,ZHONG Yong,SU Hong,WANG Cheng-zhang,WU Shuai.Influence of Natural Environment-Fatigue Alternate Action on Accumulated Damage of 2024 Typical Connection Structure[J].Surface Technology,2020,49(10):268-275 |
| 自然环境-疲劳交替作用对2024典型连接结构累积损伤的影响研究 |
| Influence of Natural Environment-Fatigue Alternate Action on Accumulated Damage of 2024 Typical Connection Structure |
| 投稿时间：2020-06-15 修订日期：2020-10-20 |
| DOI：10.16490/j.cnki.issn.1001-3660.2020.10.031 |
| 中文关键词: 连接结构 环境腐蚀 疲劳 交替作用 损伤规律 损伤机制 |
| 英文关键词:connection structure environmental corrosion fatigue alternate action damage rule damage mechanism |
| 基金项目: |
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| Author | Institution |
| SU Yan | Southwest Institute of Technology and Engineering, Chongqing 400039, China |
| ZHONG Yong | Southwest Institute of Technology and Engineering, Chongqing 400039, China |
| SU Hong | Southwest Institute of Technology and Engineering, Chongqing 400039, China |
| WANG Cheng-zhang | Southwest Institute of Technology and Engineering, Chongqing 400039, China |
| WU Shuai | Southwest Institute of Technology and Engineering, Chongqing 400039, China |
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| 中文摘要: |
| 目的 揭示自然环境和疲劳交替作用下，2024典型连接结构环境损伤规律与损伤机制。方法 采用静态暴露试验和静态暴露-疲劳交互试验，对比研究2024典型连接结构的累积损伤特性和疲劳寿命退化规律。通过电液伺服材料试验机测试不同试验周期的试样疲劳寿命，利用环境扫描电镜（SEM）和金相显微镜（OM）观察和表征试样疲劳断口形貌及微观腐蚀特征，利用X射线应力分析仪测量了周期加载引起的孔边残余应力变化。结果 金相分析结果表明，周期疲劳加载对2024连接结构的腐蚀损伤进程有一定加速性，交互试验2年的腐蚀深度（51.9 μm）大于静态暴露试样（47.0 μm）。中值疲劳寿命变化曲线显示，相同环境腐蚀条件下，静态暴露的试样疲劳寿命较“疲劳+静态暴露”交互试验方式有所提高，裸材试样的中值疲劳寿命约为交互试验的1.5～2.3倍，带涂层试样的中值疲劳寿命约为交互试验的1.1～1.4倍。紧固孔周边残余应力检测数据表明，受外加交变应力和环境腐蚀的叠加作用，孔边残余压应力逐渐减小，产生局部塑性变形，这会对疲劳寿命造成不利影响。结论 “疲劳+静态暴露”交互试验条件下的试样疲劳寿命退化与低载锻炼效应和电化学效应相互竞争、孔边残余压应力变化及微动磨损密切相关，从而呈现出先升高、后小幅振荡下降的趋势。 |
| 英文摘要: |
| The work aims to exhibit the environmental damage rule and damage mechanism of 2024 typical connection structure under the alternate action of natural environment and fatigue. Static natural exposure test and static natural environment-fatigue alternate test were used to comparatively study the accumulated damage characteristics and fatigue degradation rule of 2024 typical connection structure. Electro-liquid servo material test machine was applied to test the fatigue life of samples for different cycles. Environmental SEM and optical microscopy were adopted to observe and characterize the morphology and micro corrosion characteristics of sample fatigue fracture. The X-ray stress analyzer was employed to measure the change of residue stress at hole edge by periodical stress. Metallographic results showed that periodical fatigue stress had certain accelerating effects on corrosion damage of 2024 typical connection structure, and the corrosion depth (51.9 μm) under alternate condition for 2 years was larger than that (47.0 μm) in static exposure condition. Median fatigue life curve showed that the samples with the same environmental corrosion conditions in static exposure test had longer fatigue life than that in “fatigue + static exposure” alternate condition. The median fatigue life of samples without coating was about 1.5~2.3 times that in alternate test, and that of coated samples was about 1.1~1.4 times that in alternate test. The test data of residual stress around the fastening hole showed that the residual compressive stress at the edge of the hole gradually decreased due to the superposition of external alternate stress and environmental corrosion, resulting in local plastic deformation, which adversely affected the fatigue life. Under the condition of “fatigue+static exposure” alternate test, the fatigue life degradation of samples is closely related to the competition between low load exercise effect and electrochemical effect, the change of residual compressive stress at the hole edge and fretting wear, thus showing a trend of first increasing and then slightly oscillating and decreasing. |
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