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章根德 《非线性动力学学报》1998,5(2):117-125
本文提出描述非线性响应的砂擀土本构模型,由本构模型计算所得到的理论曲线与实验曲线发接近此模型能广泛地用于土工问题的弹一塑性有限元分析中。 相似文献
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双向加载条件下尼龙6-橡胶复合材料的应力松弛研究 总被引:1,自引:0,他引:1
在双向测试系统上进行了不同纵向应变与不同横向应变的双向松弛实验,研究了在双向拉伸载荷作用下单向尼龙6-橡胶复合材料的应力松弛特性.为了预测尼龙6-橡胶复合材料的应力松弛规律,提出了一个松弛型本构模型.当试件承受双向拉伸载荷作用时,将松弛型本构模型获得的理论曲线和实验数据进行了对比,二者取得了较好的一致性. 相似文献
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双基推进剂的高应变率力学特性及其含损伤ZWT本构 总被引:1,自引:0,他引:1
为了解双基推进剂在冲击载荷下的力学特性及本构行为,利用材料试验机和分离式霍普金森压杆(SHPB)对双基推进剂进行了单轴压缩实验,并对实验数据的有效性进行了检验。用二波法对实验数据进行处理,得到了双基推进剂的应力应变曲线。实验结果表明:双基推进剂具有明显的应变率相关性,动态下屈服应力与静态下相比明显提高,且屈服应力表现为应变率对数的双线性关系;双基推进剂屈服应变表现为延脆转换特性,在低应变率下表现为延展性,高应变率下表现为冲击脆化特性。利用含损伤朱王唐(ZWT)本构模型对实验结果进行了拟合,得到了模型中的本构参数,并对损伤因子项进行了分析。通过模型预测曲线与实验曲线的对比,发现含损伤ZWT本构能较好地描述双基推进剂在0~0.14应变范围内的力学特性。 相似文献
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针对粘弹塑性统一本构模型参效众多的特点和传统评估参效方法的缺点,应用非线性最小二秉法与敏感系数分析方法相结合,提出了一个比较系统的对粘弹塑性统一本构模型的参数进行评估的方法。对铜合金在室温下不同加载速率的试验曲线进行参数适配,表明本方法的合理性与正确性。为粘弹塑性统一本构模型的工程应用奠定了基础。 相似文献
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为了研究聚乙烯材料在不同应变率下的压缩力学性能,通过准静态实验和动态实验获得聚乙烯材料不同应变率下的应力应变曲线,分析发现:聚乙烯的弹性模量和屈服强度随应变率增大而增大,具有明显的黏弹塑性;聚乙烯材料进入塑性阶段,其应力应变曲线在不同应变率下具有相近的变化趋势,即塑性切向模量近似相同。根据聚乙烯材料的压缩力学性能,建立了弹性区、屈服点和塑性区的分段本构模型。该模型的屈服点和塑性段与实验结果吻合较好,由于弹性段采用线弹性模型,与实验结果存在一定偏差,可近似描述材料的弹性行为。 相似文献
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运用Holmquist-Johnson-Cook (HJC) 本构模型对混凝土的SHPB实验进行了数值模拟。解决了罚函数算法中罚因子合理数值的选取问题。利用模拟结果按SHPB两波法重构了试样的应力应变曲线。分析了混凝土材料的SHPB实验得到应力应变曲线的有效段范围和各段的力学规律。通过比较实际混凝土材料SHPB实验和数值模拟得到的应力应变曲线,发现两者体现的力学行为很相似,即HJC模型是描述该类材料的一种合理本构模型。模拟了试样不同平行度公差下的SHPB实验,发现在一定应变率范围内其影响程度远大于试样应力(应变)不均匀性。 相似文献
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IntroductionAcompanionpaper [1 ]describedastressvector_basedconstitutivemodelforcohesionlesssoil.Themodelisbasedontheequivalentdecompositionoftheactioneffectofstressvectorforthemain .Thatis ,underplanestraincondition ,theactioneffectofstressvectorcanbeequi… 相似文献
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含损伤的冻土本构模型及耦合问题数值分析 总被引:7,自引:1,他引:7
从复合材料的细观力学机理出发,建立了含损伤的冻土弹性本构模型. 对于在不同冰体积
含量和不同温度下的冻结砂土,由该损伤本构模型计算的结果与实测的应力-应变曲线比较
吻合. 利用自主开发的程序,分别对渠道冻结和冻土路基的水分场、温度场、应力场3场耦
合进行数值模拟,得到了比较准确、详尽的符合实际的温度场与应力场、位移场、应变场耦
合的计算结果,与前人的计算及实测结果相符合,规律一致. 表明该程序能够计算冻土材料
的相关物理量,并能很好地描述这些相关物理量之间的关系. 相似文献
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The stress vector-based constitutive model for cohesionless soil, proposed by SHI Hong-yan et al., was applied to analyze
the deformation behaviors of materials subjected to various stress paths. The result of analysis shows that the constitutive
model can capture well the main deformation behavior of cohesionless soil, such as stress-strain nonlinearity, hardening property,
dilatancy, stress path dependency, non-coaxiality between the principal stress and the principal strain increment directions,
and the coupling of mean effective and deviatoric stress with deformation. In addition, the model can also take into account
the rotation of principal stress axes and the influence of intermediate principal stress on deformation and strength of soil
simultaneously. The excellent agreement between the predicted and measured behavior indicates the comprehensive applicability
of the model.
Biography: SHI Hong-yan (1962-), Associate Professor, Doctor 相似文献
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IntroductionOneoftheprimaryproblemsingoetechnicalengineeringistoconstructasoilconstitutivemodelapplicabletogeneral 3_Dstressstates.Althoughmanytypesofconstitutivemodelshavebeenproposed ,fewcantakeproperaccountofthedirectionalchangeofstressvector (i.e .,ro… 相似文献
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On the basis of the sufficient consideration of vectorial characteristics of stress, a new nonlinear constitutive model for
cohesionless soil under plane strain and 3-D conditions was presented in a way that the action effects of stress vector are
decomposed into the action effect of mean effective stress and that of the stress ratio vector (ratio of deviatoric stress
vector to mean effective stress). The constitutive model can take account of the influence of both numerical and directional
changes of stress vector on deformation of soil simultaneously, and is applicable of both static and dynamic loading.
Biography: Shi Hong-yan (1964-) 相似文献
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DOUBLE-MEDIUM CONSTITUTIVE MODEL OF GEOLOGICAL MATERIAL IN UNIAXIAL TENSION AND COMPRESSION 总被引:1,自引:0,他引:1
Based on elasto-plasticity and damage mechanics, a double-medium constitutive model of geological material under uniaxial tension and compression was presented, on the assumption that rock and soil materials are the pore-fracture double-medium, and porous medium has no damage occurring, while fracture medium has damage occurring with load. To the implicit equation of the model, iterative method was adopted to obtain the complete stress-strain curve of the material. The result shows that many different distributions (uniform distribution, concentrated distribution and random distribution) of fractures in rock and soil material are the essential reasons of the daedal constitutive relations. By the reason that the double-medium constitutive model separates the material to be porous medium part, which is the main body of elasticity, and fracture medium part, which is the main body of damage, it is of important practical values and theoretical meanings to the study on failure of rock and soil or materials containing damage. 相似文献
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Paul Hölscher 《Transport in Porous Media》1992,9(1-2):73-84
The behaviour of the soil under a dynamically loaded pile toe is studied. The soil is modelled as a fluid saturated porous continuum. The constitutive behaviour of the solid skeleton is described by the elasto-plastic model of Drücker-Prager. The wave propagation is simulated with a dynamical finite-element program.A two-phase model of soil gives useful information about effective stress and pore pressure in the soil. In saturated soil the main wave under the pile toe propagates more downards than in dry soil, due to the higher compressional stiffness in saturated soil. The plastic zone under the pile toe propagates with the velocity of the fast compressional wave. The pore fluid influences the plasticity strongly and can be expected to affect pile driving too.The distribution of effective stress and pore pressure under the pile toe depends on the permeability of the soil and cannot be calculated uniquely from a single-phase calculation. Therefore, a nonlinear soil cannot be modelled correctly as a conventional single-phase material. 相似文献
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Uniaxial and non-proportionally multiaxial ratcheting of SS304 stainless steel at room temperature: experiments and simulations 总被引:1,自引:0,他引:1
The uniaxial and non-proportionally multiaxial ratcheting behaviors of SS304 stainless steel at room temperature were initially researched by experiment and then were theoretically described by a cyclic constitutive model in the framework of unified visco-plasticity. The effects of cyclic stress amplitude, mean stress, and their histories on the ratcheting were experimentally investigated under uniaxial and different multiaxial loading paths. The shapes of non-proportional loading paths were linear, circular, elliptical and rhombic, respectively. In the constitutive model, the rate-dependent behavior of the material was reflected by a viscous term; the cyclic flow and cyclic hardening behaviors of the material under asymmetrical stress-controlled cycling were reflected by the evolution rules of kinematic hardening back stress and isotropic deforming resistance, respectively. The effect of loading history on the ratcheting was also considered by introducing two fading memorization functions for maximum inelastic strain amplitude and isotropic deformation resistance, respectively, into the constitutive model. The effect of multiaxial loading path on the ratcheting was reflected by a non-proportional factor defined in this work. The predicting ability of the developed model was proved to be good by comparing the simulations with corresponding experiments. 相似文献
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在长期交通载荷作用下土体塑性累积变形本构模型对路基沉降计算至为关键.元件组合模型可以计算岩土体循环累积应变,但现有的各类元件模型未能反映饱和软黏土的主应力轴循环旋转现象.在对饱和软黏土进行等向固结条件下的主应力轴循环旋转加载试验及非等向固结下的循环扭剪试验基础上,将Abel黏壶代替Burgers模型中的Newton黏壶,得到分数阶Burgers模型;利用遗传算法优化循环塑性累积应变的Burgers模型和分数阶Burgers模型的参数,通过对比两组模型的计算值与试验值,发现分数阶模型更适合模拟计算循环载荷下饱和软黏土的累积变形. 相似文献