Empirical formulation of stress concentration factor around an arbitrary-sized spherical dual-cavity system and its application to aluminum die castings
Empirical formulation of stress concentration factor around an arbitrary-sized spherical dual-cavity system and its application to aluminum die castings
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DOI：
10.1016/j.apm.2015.01.032
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发表时间：
2015-09
影响因子：
5
通讯作者：
S. Bidhar;O. Kuwazuru;Y. Shiihara;T. Utsunomiya;Y. Hangai;M. Nomura;I. Watanabe;N. Yoshikawa
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文献类型：
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作者：
S. Bidhar;O. Kuwazuru;Y. Shiihara;T. Utsunomiya;Y. Hangai;M. Nomura;I. Watanabe;N. Yoshikawa
对于任意方位的不等尺寸孔对，导出了应力集中系数的经验公式。进行三维有限元线弹性分析，以评估不同尺寸，方向和分离的空腔的应力集中系数。选择合适的数学函数来拟合有限元分析的数值结果。给出了一个计算发动机缸体铝合金压铸件疲劳裂纹萌生的最大应力集中系数的应用实例。从X射线CT图像，气体孔隙的位置和几何形状进行评估，从而开发出建议的经验公式，这个实际的多孔系统简化为一个双球孔系统。通过与体素有限元分析的比较，证明了该公式。从疲劳裂纹萌生的角度出发，提出的经验公式可作为选择汽车发动机缸体铸造方法的科学依据。
An empirical formula for the stress concentration factor is developed for an unequal-sized cavity pair in an arbitrary orientation. Three-dimensional finite element linear elastic analyses are performed to evaluate the stress concentration factors for different sizes, orientations, and separations of cavities. A suitable mathematical function is chosen to fit the numerical results of the finite element analyses. An application is given for evaluating the maximum stress concentration factor, which governs fatigue crack initiation in aluminum die cast test pieces from an engine block. From the X-ray CT image, the location and geometry of the gas pores are evaluated so as to develop the proposed empirical formula for this actual multi-pore system simplified to a dual spherical pore system. A proof of the formula is shown by comparison with voxel finite element analysis. The proposed empirical formula can be satisfactorily used as a scientific guideline for selecting a casting method for car engine blocks from a fatigue crack initiation perspective.