共查询到20条相似文献,搜索用时 46 毫秒
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本文借助于热辐应力图像分析技术记录了铝质紧养伤拉伸试件的热辐射应力图像。根据裂尖周围温度变化曲线的分布规律确定其特征区的,从而得以裂尖塑性区的开头曲线,并与理论值比较,符合良好。对裂纹扩展面进行SEM分析,得出该试件的断裂特性,对于进行细观损伤研究有重要的意义。 相似文献
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循环塑性区大小是疲劳断裂研究中非常重要的一个参数.本文运用数值方法,考察了不同塑性本构模型、有限单元尺寸、几何非线性、载荷比等参数对于裂纹尖端疲劳塑性区大小的影响.结果发现除塑性本构模型外其他参数对于裂纹尖端疲劳塑性区大小影响不大.同时对Ⅰ、Ⅱ型混合裂纹在多轴非比例载荷下给出了由Jiang和Kurath定义的疲劳塑性区... 相似文献
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基于Kane-Mindlin关于弹性平板面内问题位移的运动学假设,本文首次推导了一种考虑板厚效应的平板面内问题的有限元格式。将Kane-Mindl.n假设推广到弹塑性问题,推导了相应的有限元方程.对双边及中心裂纹拉伸试件的计算结果表明,裂纹尖端附近的弹性三维效应区尺寸和板厚相当.对线性硬化弹塑性材料,当切线模量E_t和弹性模量E之比E_t/E大于0.2时,三维效应区在两倍板厚以内. 相似文献
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Shih[1]应用奇异单元,获得了不考虑应力松驰小范围屈服条件下复合型裂纹尖端塑性区形状。Z.Z.Zu等[2]采用Rice[5]给出的裂纹尖端应力关系式,利用有限元分析获得了不考虑应力松驰下复合型裂纹尖端塑性区,本文基于静力学中内力与外力平衡条件,用线弹性的全场解代替局部解,给出了考虑应力松驰下复合型裂纹尖端塑性区边界方程,获得了考虑应力松驰下的任意方向的塑性区尺寸及塑性区形状 相似文献
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采用弹性-粘塑性本构模型,对幂硬化粘塑性介质中反平面剪切动态扩展裂纹尖端的应力,应变场进行了渐近分析,给出了反平面剪切动态扩展纹尖端场的渐进方程。分析结果表明,在裂纹法端应力具有(lnR/r)1/n-1的奇异性,应变具有(lnR/Rn/n-1的奇异性。从而提示了幂硬化粘塑材料反平面剪动态扩展裂纹尖端场的渐近行为。 相似文献
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裂尖曲率对裂纹前缘塑性区的影响 总被引:1,自引:0,他引:1
考虑尖端为圆弧形的钝头裂纹模型,在外围取线弹性无裂纹体的解,应用线场分析方法。形成一套估计钝头裂纹前缘塑性区尺寸的方法。对含径向裂纹和圆弧形裂尖的圆盘受均匀张力作用情况,给出了塑性区的裂纹前缘尺寸与裂纹尖端曲率的关系。得到的结论是,塑性区的裂纹前缘尺寸与裂纹尖端曲率有关;对于给定的塑性区的裂纹前缘尺寸,载荷反比于外缘尺寸的平方。前一结论说明了塑性区的裂前尺寸作为裂纹失稳扩展判断的局限性;后一结论说明了裂纹体强度失效的尺寸效应规律:抗断强度与总体线尺寸的平方成反比。 相似文献
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The plastic zone at a crack tip in a finite anisotropic body is studied. A boundary-value problem is formulated in terms of
the components of the covariant displacement vector for small strains. Particular attention is given to the case of plain
strain. In this case, a numerical solution is found for a long rectangular body with a central crack under tension. As a result,
conditions for the occurrence and development of a plastic zone at the crack tip are established. A plastic zone on the lateral
surface of the body is discovered. How both zones extend and coalesce is elucidated. The effect of anisotropy on the occurrence
of a plastic zone is evaluated
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 7, pp. 29–44, July 2006. 相似文献
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叶志明 《应用数学和力学(英文版)》1998,19(1):37-43
1.IntroductionBynowfracturemechanicsisuniversallyacknowledgedasthetoolofanalysingtheinveshgationofconcretecracking.Andaftermanyyearsofdevelopmentonnumerousconstitutivemodelsforuniaxial,biaxialandtriaxialmodelsofconcreteundercompressivestresses,andtheirvariousrefinements,researchershavefinallyturnedtheirattentiontothecornerofthestressstraincurveandaregivingmoreattentiontotheeffectofcrackingonthenonlinearresponse.ofconcretestructures.Havingexperimentallyobservedthatthemacroscopicresponseofconcre… 相似文献
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The influence of the length of a mode I crack on the plastic zone in an anisotropic body under hard loading is studied. The
case of a generalized plane stress state is examined. A boundary-value problem is solved numerically to study the behavior
of the main plastic zone at the crack tip, the additional plastic zone on the lateral face of the body, and the merged plastic
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Translated from Prikladnaya Mekhanika, Vol. 44, No. 9, pp. 36–52, September 2008. 相似文献
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林拜松 《应用数学和力学(英文版)》1993,14(7):643-648
On condition that any perfectly plastic stress component at a crack tip is nothingbut the function ofθ.by making use of equilibrium equations,anisotropic plastic stress-strain-rate relations,compatibility equations and Hill anisotropic plastic yieldcondition,in the present paper,we derive the generally analytical expressions of theanisotropic plastic stress field at a mixed-mode crack tip under plane and anti-planestrain.Applying these generally analytical expressions to the mixed-mode cracks,wecan obtain the analytical expressions of anisotropic plastic stress fields at the tips ofmixed-modeⅠ-Ⅲ,Ⅱ-ⅢandⅠ-Ⅱ-Ⅲcracks. 相似文献
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The effects of tension and compression along a crack on the plastic zone in a finite anisotropic body under plane strain are
studied. The formation pattern for the plastic zone with increasing load is established by numerically solving a boundary-value
problem for each of the cases. In particular, a new plastic zone is revealed. It occurs at the crack face under a compressive
load of certain magnitude. How this plastic zone interacts with that at the crack tip is established
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 5, pp. 3–19, May 2007. 相似文献
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EXACT SOLUTIONS OF NEAR CRACK LINE FIELDS FOR MODE I CRACK UNDER PLANE STRESS CONDITION IN AN ELASTIC-PERFECTLY PLASTIC SOLID 总被引:1,自引:1,他引:1
EXACTSOLUTIONSOFNEARCRACKLINEFIELDSFORMODEICRACKUNDERPLANESTRESSCONDITIONINANELASTIC-PERFECTLYPLASTICSOLIDEXACTSOLUTIONSOFNEA... 相似文献
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The elastic-plastic stress distribution and the elastic-plastic boundary con- figuration near a crack surface region are significant but hard to obtain by means of the conventional analysis. A crack line analysis method is developed in this paper by consid- ering the crack surface as an extension of the crack line. The stresses in the plastic zone, the length, and the unit normal vector of the elastic-plastic boundary near a crack surface region are obtained for an antiplane crack in an elastic-perfectly plastic solid. The usual small scale yielding assumptions are not needed in the analysis. 相似文献
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In this paper, double dissimilar orthotropic composite materials interfacial crack is studied by constructing new stress functions and employing the method of composite material complex. When the characteristic equations' discriminants △1 〉 0 and △2 〉0, the theoretical formula of the stress field and the displacement field near the mode I interface crack tip are derived, indicating that there is no oscillation and interembedding between the interfaces of the crack. 相似文献
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In this paper, a deformation theory of plasticity for damaged materials is proposed. An asymptotic expression forH near a crack tip is obtained. Finally, the stress and strain fields near the crack tip are presented. 相似文献
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In this paper,a weighted residual method for the elastic-plastic analysis near a crack tip is systematically given by taking the model of power-law hardening under plane strain condition as a sample.The elastic-plastic solutions of the crack tip field and an approach based on the superposition of the nonlinear finite element method on the complete solution in the whole crack body field,to calculate the plastic stress intensity factors,are also developed.Therefore,a complete analysis based on the calculation both for the crack tip field and for the whole crack body field is provided. 相似文献