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本文介绍一种由临近缝端的等色线条纹图确定混合型应力强度因子K_I与K_(II)的新方法——等参数法。基于断裂力学的理论,作者提出一种用来确定混合型应力强度因子的光弹性分析方法。阐明了非单一的远场应力σ_(ox)的效应。涉及K_I、K_(II)和σ_(ox)的应力场系由非线性方程式来表明,与该应力场以相应的等色线条纹级数所在点的座标函数γ与θ来描述。 这种考虑远场应力的高精确度的方法是以严谨的理论为依据的,能应用于各种不同形态的缝端应力场。对于任何团合的或发散的等色线条纹图,它均可用于估价裂缝区中的张开型及滑移型应力强度因子。 解决的方式包含了重复的数据运算处理,成果分析的方式包含了重复的数据运算处理。然而,当测取r及N时,已考虑了试验误差;所以这种重复运算很快就得到收敛,其计算量是很小的。这种方法通常可应用全场的条纹图资料,并有效地增加了确定K_I、K_(II)和σ_(ox)的精确性。 此外,当不计及远场应力时,研究的结果给出了十分简便的计算公式。 本文阐明了混合型应力强度因子的光弹性理论分析及其试验研究,并用于确定有缝的工程结构的应力强度因子。最后,讨论了应用等参数法研究应力强度因子的一些值得注意的问题,推荐了人工裂缝的模拟方法,阐明了应力强度因子的取值、缝端半径?
In this paper, we introduce a new method to determine the mixed stress intensity factors K_I and K_ (II) from the isochromatic line fringes near the seam end - the isoparametric method. Based on the theory of fracture mechanics, the authors propose a photoelastic analysis method to determine the mixed stress intensity factor. The effect of non-uniform far-field stress σ_ (ox) is clarified. The stress fields related to K_I, K_ (II) and σ_ (ox) are shown by the nonlinear equation, which is described by the coordinate functions γ and θ of the points where the corresponding isochromatic line fringes are located. This high-precision method of considering far-field stress is based on rigorous theory and can be applied to a variety of different forms of seam end stress field. It can be used to estimate open and slipping stress intensity factors in any fractured zone for any coherent or divergent isochromatic fringe pattern. The solution includes repeated data operations, and the result analysis includes repeated data operations. However, when r and N are taken into account, experimental errors have been taken into account; therefore, this iterative operation converges very quickly and the computational effort is small. This method generally applies full-field fringe pattern data and effectively increases the accuracy of determining K_I, K_ (II) and σ_ (ox). In addition, the results of the study give very simple formulas when the far field stresses are not taken into account. In this paper, the theory of photoelasticity of mixed stress intensity factor and its experimental study are illustrated and used to determine the stress intensity factor of the cracked engineering structure. Finally, some important problems that should be noticed when applying the isoparametric method to study the stress intensity factor are discussed. The artificial fracture simulation method is recommended, and the value of the stress intensity factor and the radius of the seam end are expounded.