Simulation Study on Fatigue Growth of Semi-Circular Axial Crack on Inner Surface of Core Barrel under Transient Loads
-
摘要: 为研究瞬态载荷下堆芯筒体内表面裂纹疲劳扩展，采用Zencrack软件中的裂纹块分析方法，对反应堆压力容器堆芯筒体内表面含半圆形轴向裂纹（裂纹深度d为10 mm，裂纹表面长度l 为20 mm）在瞬态载荷下的裂纹形貌变化规律进行了仿真模拟研究，其中采用子程序对堆芯筒体材料的疲劳裂纹扩展速率模型进行了实现。通过仿真研究可知：材料疲劳裂纹扩展速率模型的子程序实现是分析裂纹疲劳扩展模拟的一种高效方式；裂纹块分析方法计算得到的应力强度因子与规范工程化分析方法计算得到的结果是相当的；堆芯筒体内表面初始态为半圆形的轴向裂纹，在瞬态载荷下其裂纹疲劳扩展会出现初始态裂纹椭圆化的过程。Abstract: In order to study the fatigue growth of inner surface cracks in the core barrel under transient loads, the change law of crack morphology of semi-circular axial crack (crack depth d is 10 mm and crack surface length L is 20 mm) on the inner surface of reactor pressure vessel core barrel under transient load is simulated by using the crack block analysis method in the Zencrack software, wherein, the fatigue crack growth rate model of core cylinder material is realized by subprogram. Through the simulation study, it is known that the subprogram realization of material fatigue crack growth rate model is an efficient way to analyze the simulation of crack fatigue growth; the stress intensity factor calculated by the crack block analysis method is similar to that calculated by the standard engineering analysis method;. For the axial cracks with a semi-circular initial state on the inner surface of the core barrel, the initial crack ovalization will occur during the fatigue growth of the crack under transient loads.
-
Key words:
- Crack fatigue growth /
- Core barrel /
- Semi-circular axial crack /
- Transient loads
-
图 3 植入裂纹块后裂纹区域的有限元模型
Figure 3. Finite Element Model of Crack Region after Crack Block Implantation
图 5 裂纹块分析方法得到的内表面轴向真实裂纹前缘各点K值变化
Figure 5. Change of K at Each Point of Inner Surface Axial Real Crack Front Edge Calculated by Crack Block Analysis Method
图 7 裂纹块分析方法计算得到的K值与RSE-M规范方法计算得到的K值比较
Figure 7. K Calculated by Crack Block Analysis Method is Compared with that Calculated by RSE-M Code Method
图 9 裂纹块分析方法和RSE-M规范方法计算疲劳裂纹扩展规律对比结果
Figure 9. Comparison Results of Fatigue Crack Growth Law Calculated By Crack Block Analysis Method and RES-M Code Method
表 1 PWR环境下16MND5材料的疲劳裂纹扩展速率
Table 1. Fatigue Crack Growth Rate of 16MND5 under PWR Environment
环境 R ΔK/ (MPa·m0.5) ${ { {\dfrac{ { {\text{d} }a} }{ { {\text{d} }N} } } }}\Big/$(mm·cycle−1) 压水堆 <0.3 ΔK<16.5 取下列式中较保守的值：
da/dN=1.635×10−13(ΔK)8；da/dN=7.947×10−9(ΔK有效)2.927；
ΔK有效= Kmax(1−R)0.7516.5<ΔK≤100 da/dN=1.983×10−5 (ΔK)1.4 ΔK＞100 da/dN=4.754×10−10 (ΔK)3.726 ≥0.6 ΔK<12 取下列式中较保守的值：da/dN=5.214×10−12(ΔK)8；da/dN=7.947×10−9(ΔK有效)2.927；
当R≤0.9：ΔK有效= Kmax(1R)0.75；当R＞0.9：ΔK有效=ΔK (1−R/2)；ΔK≥12 da/dN=7.03×10−5(ΔK)1.4 da/dN=C(ΔK)m或da/dN=C(ΔK有效)m；ΔK有效—引起裂纹扩展的有效应力强度因子范围；Kmax—最大应力强度因子； C—裂纹扩展速率中的系数；m—裂纹扩展速率中的指数系数；da/dN——每一循环的裂纹扩展速率 
下载: 导出CSV
表 2 裂纹形貌中裂纹深点和表面点的尺寸
Table 2. Size of Deep and Surface Points in Crack Morphology
计算
方法瞬态 d/mm l/mm t/mm 裂纹块 初始态 10.00 20.00 200.00 瞬态（升温） 10.16 20.20 200.00 瞬态（升温） 10.50 20.65 200.00 瞬态（降温） 11.78 22.20 200.00
下载: 导出CSV
-
[1] NANSTAD R K, CORWIN W R, ALEXANDER D J, et al. Heavy-Section steel irradiation program on irradiation effects in light-water reactor pressure vessel materials: CONF-950740-66[R]. Tennessee: ORNL, 1995. [2] NGUYEN H Q, GALLIMARD L, BATHIAS C. Numerical simulation of fish-eye fatigue crack growth in very high cycle fatigue[J]. Engineering Fracture Mechanics, 2015, 135: 81-93. doi: 10.1016/j.engfracmech.2015.01.010 [3] PARIS P C, ERDOGAN F. A critical analysis of crack propagation laws[J]. Journal of Fluids Engineering, 1963, 85(4): 528-533. [4] FORMAN R G, KEARNEY V E, ENGLE R M. Numerical analysis of crack propagation in cyclic-loaded structures[J]. Journal of Fluids Engineering, 1967, 89(3): 459-463. [5] WALKER K. The effect of stress ratio during crack propagation and fatigue for 2024-T3 and 7075-T6 Aluminum[J]. Effects of Environment and Complex Load History on Fatigue Life, ASTM Special Technical Publication, 1970, 462: 1-14. [6] ZENCRACK. User’s Manual for 8.2[M]. London: Zentech International Ltd, 2017: 10-173. [7] AFCEN. In-service inspection rules for mechanical components of PWR nuclear islands: RSE-M[S]. Paris: AFCEN, 2010: 979-988. -
计量
- 文章访问数: 258
- HTML全文浏览量: 64
- PDF下载量: 31
- 被引次数: 0
