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硬度影响压痕弹塑性行为的有限元分析 被引量:3
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作者 孙渊 王庆明 《机械设计与研究》 CSCD 北大核心 2007年第4期69-73,共5页
以具有不同硬度40Cr为研究对象,根据集中载荷下的接触模型和赫兹理论,计算了压痕接触半径和压痕附近弹性区域的表面局部接触应力,并采用有限元法,分析硬度物理量对压痕弹塑性行为、局部接触应力、卸载后保留在内部的残余应力的影响,探... 以具有不同硬度40Cr为研究对象,根据集中载荷下的接触模型和赫兹理论,计算了压痕接触半径和压痕附近弹性区域的表面局部接触应力,并采用有限元法,分析硬度物理量对压痕弹塑性行为、局部接触应力、卸载后保留在内部的残余应力的影响,探讨压痕参数、压痕接触应力、残余应力与硬度之间的关系以及载荷增加时它们的发展。结果表明,相同载荷下塑性隆起量、压痕接触半径、压痕量和塑性区范围随着硬度值的提高而减小,弹性回弹量、最大接触应力和残余应力随硬度提高而增加;压痕周围处接触应力和残余应力、其分布范围和塑性区域随载荷的增加而增加。 展开更多
关键词 硬度 压痕 弹塑性行为 有限元分析
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汽车发动机气缸体铝合金319的蠕变和弹塑性行为分析 被引量:1
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作者 梁代春 程飞 《热加工工艺》 CSCD 北大核心 2013年第20期85-87,90,共4页
基于NAFEMS标准,通过在铝合金319厚壁汽缸上加载非比例载荷,建立了汽车发动机铝合金319的非线性材料模型,以模拟汽车发动机汽缸体铝合金319的非线性应力应变以及蠕变和弹塑性行为。结果表明:利用所建立弹塑性和蠕变模型获得的在汽缸内... 基于NAFEMS标准,通过在铝合金319厚壁汽缸上加载非比例载荷,建立了汽车发动机铝合金319的非线性材料模型,以模拟汽车发动机汽缸体铝合金319的非线性应力应变以及蠕变和弹塑性行为。结果表明:利用所建立弹塑性和蠕变模型获得的在汽缸内壁上的蠕变计算曲线和NAFEMS标准的目标数据取得了很好的拟合,这说明利用NAFEMS基准模型可预测发动机汽缸内表面的等效蠕变应变的时间历程。 展开更多
关键词 汽缸体 铝合金319 蠕变 弹塑性行为
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碳微球的纳米压痕弹塑性行为的研究
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作者 孙渊 张栋 孙利 《上海电机学院学报》 2019年第3期125-129,共5页
通过光学显微镜和原子力显微镜观察到碳微球的结构,采用纳米压痕法研究碳微球的压痕弹塑性行为以及基体效应,分析了载荷作用下最大压痕深度、弹性回弹量、弹性能和弹性回复率等弹性性能。研究表明:碳微球在最大压痕深度与微球半径的比值... 通过光学显微镜和原子力显微镜观察到碳微球的结构,采用纳米压痕法研究碳微球的压痕弹塑性行为以及基体效应,分析了载荷作用下最大压痕深度、弹性回弹量、弹性能和弹性回复率等弹性性能。研究表明:碳微球在最大压痕深度与微球半径的比值(h_m/R)超过0.1时,其压痕行为受到基体的影响,在载荷为75μN下,h_m/R为0.16~0.17时,所测得的接触弹性模量值误差将接近50%,并随着载荷的增加,h_m/R增加,误差也随之增加;碳球的回弹率和弹性回复能力随着载荷的增加而下降,说明在较高载荷下产生了较大的不可回复的塑性变形和储存了较大的弹塑性能。 展开更多
关键词 碳微球 纳米压痕法 压入响应 基体效应 弹塑性行为
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局部载荷下材料性能影响压痕弹塑性行为的研究 被引量:2
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作者 孙渊 王庆明 《上海电机学院学报》 2008年第2期99-103,109,共6页
利用有限元法分析了不同材料在载荷作用下接触区域的弹塑性行为,探讨了弹塑性行为与载荷、屈服强度、弹性模量和泊松比之间的关系,并构建1套压痕实验装置予以实验验证。研究结果表明:载荷、材料屈服强度对压痕弹塑性行为影响大,而弹性... 利用有限元法分析了不同材料在载荷作用下接触区域的弹塑性行为,探讨了弹塑性行为与载荷、屈服强度、弹性模量和泊松比之间的关系,并构建1套压痕实验装置予以实验验证。研究结果表明:载荷、材料屈服强度对压痕弹塑性行为影响大,而弹性模量、泊松比对其压痕弹塑性行为影响较小。研究结果描述了载荷增加时其压痕弹塑性行为的发展,压痕参数与屈服强度之间的关系,为压痕法根据压痕参数确定屈服强度提供参考。 展开更多
关键词 材料性能 有限元分析 弹塑性压痕行为 实验研究
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微结构对金属基复合材料宏观弹塑性性能的影响 被引量:3
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作者 陈浩然 苏晓风 唐立民 《固体力学学报》 CAS CSCD 北大核心 1996年第2期103-108,共6页
采用广义自洽有限元迭代平均化方法分析SiC晶须增强铝基复合材料的弹塑性拉伸行为,研究纤维长径比与体分比的变化对复合材料宏观弹塑性变形的影响.通过细观应力场的分析,讨论基体内塑性区的发展与复合材料宏观弹塑性变形过程之间... 采用广义自洽有限元迭代平均化方法分析SiC晶须增强铝基复合材料的弹塑性拉伸行为,研究纤维长径比与体分比的变化对复合材料宏观弹塑性变形的影响.通过细观应力场的分析,讨论基体内塑性区的发展与复合材料宏观弹塑性变形过程之间的联系,指出纤维端头处基体塑性区的发展将对复合材料拉伸弹塑性行为有着显著影响.最后,还讨论了以名义屈服应力σ0.2来表征金属基复合材料的弹塑性特征的不足之处. 展开更多
关键词 金属基 复合材料 微结构 宏观弹塑性行为
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组合梁上层混凝土板弹塑性与剪力度关系分析 被引量:1
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作者 郭发忠 《公路交通科技》 CAS CSCD 北大核心 2010年第8期51-54,75,共5页
为了探讨双层组合连续梁的工程力学特性,分析双层组合梁连接剪力度对上层混凝土板弹塑性行为的影响,通过有限元软件Ansys10.0建立了三维空间模型,考虑了混凝土、剪力连接件、钢梁等材料的非线性,采用非线性弹簧单元combine39模拟剪力连... 为了探讨双层组合连续梁的工程力学特性,分析双层组合梁连接剪力度对上层混凝土板弹塑性行为的影响,通过有限元软件Ansys10.0建立了三维空间模型,考虑了混凝土、剪力连接件、钢梁等材料的非线性,采用非线性弹簧单元combine39模拟剪力连接件,对双层组合梁的上层混凝土板弹塑性行为和剪力度关系进行了分析。结果表明,当剪力度增大到一定值时,开裂荷载不再随剪力度增大而增大,剪力度过大会导致上层混凝土板过早开裂,以致造成上层混凝土板承载力降低。 展开更多
关键词 桥梁工程 双层组合梁 有限元 剪力度 上层混凝土板 弹塑性行为
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C-Si-Mn冷轧双相钢的应变硬化特性 被引量:14
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作者 邝霜 康永林 +1 位作者 于浩 刘仁东 《材料工程》 EI CAS CSCD 北大核心 2009年第2期11-14,18,共5页
试制了C-Si-Mn冷轧双相钢。采用力学测试、显微组织观察与修正的C-J分析方法研究了双相钢的应变硬化特性。研究结果表明,双相钢的应变硬化具有两阶段。第一阶段应变硬化能力较强,第二阶段硬化能力减弱。两阶段硬化之间存在一个转折应变... 试制了C-Si-Mn冷轧双相钢。采用力学测试、显微组织观察与修正的C-J分析方法研究了双相钢的应变硬化特性。研究结果表明,双相钢的应变硬化具有两阶段。第一阶段应变硬化能力较强,第二阶段硬化能力减弱。两阶段硬化之间存在一个转折应变。当马氏体体积分数小于16%,随马氏体体积分数的增加,两阶段硬化能力均增强。当马氏体体积分数大于16%,随马氏体体积分数的增加,两阶段硬化能力均减弱。硬化转折应变则随马氏体体积分数增加单调递减。铁素体与马氏体的弹塑性行为差异是导致双相钢两阶段硬化的主要原因。马氏体体积分数增加,其强化效果增加,但是由于马氏体中的碳含量降低,其塑性抗力降低。只有当马氏体量增加带来的强化效应大于碳含量减少的弱化效应时,双相钢的应变硬化能力才随之增加。 展开更多
关键词 双相钢 应变硬化 弹塑性行为 马氏体
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细观参数对纤维增强金属基复合材料宏细观力学性能的影响 被引量:7
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作者 胡丽娟 张少睿 +2 位作者 李大永 苌群峰 彭颖红 《上海交通大学学报》 EI CAS CSCD 北大核心 2008年第3期475-479,共5页
B纤维、SiC纤维增强Al基及Mg基复合材料的微观参数对宏观性能具有重要影响.基于细观力学理论,利用代表性体积元(RVE)建立极坐标复合材料宏细观弹塑性本构模型,采用有限元法研究了Al基和Mg基复合材料的基体材料、纤维种类、纤维体积分数... B纤维、SiC纤维增强Al基及Mg基复合材料的微观参数对宏观性能具有重要影响.基于细观力学理论,利用代表性体积元(RVE)建立极坐标复合材料宏细观弹塑性本构模型,采用有限元法研究了Al基和Mg基复合材料的基体材料、纤维种类、纤维体积分数对复合材料整体力学性能的影响.研究结果表明:基体材料遵循自身弹塑性变化规律并引起复合材料整体的弹塑性变形,纤维保持其线弹性性能,在拉伸过程起主要承载作用;基体材料及纤维体积分数对复合材料力学性能的影响效应更强;利用宏细观本构模型计算获得的复合材料应力值与试验值接近,误差不超过2.5%. 展开更多
关键词 金属基复合材料 细观参数 宏细观弹塑性行为 数值仿真
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Visco-elastoplastic damage constitutive model for compressed asphalt mastic 被引量:1
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作者 曾国伟 杨新华 +1 位作者 白凡 高虎 《Journal of Central South University》 SCIE EI CAS 2014年第10期4007-4013,共7页
In order to describe the three-stage creep behavior of compressed asphalt mastic, a visco-elastoplastic damage constitutive model is proposed in this work. The model parameters are treated as quadratic polynomial func... In order to describe the three-stage creep behavior of compressed asphalt mastic, a visco-elastoplastic damage constitutive model is proposed in this work. The model parameters are treated as quadratic polynomial functions with respect to stress and temperature. A series of uniaxial compressive creep experiments are performed at various stress and temperature conditions in order to determine these parameter functions, and then the proposed model is validated by comparison between the predictions and experiments at the other loading conditions. It is shown that very small permanent deformation at low stress and temperature increases rapidly with elevated stress or temperature and the damage may initiate in the stationary stage but mainly develops in the accelerated stage. Compared with the visco-elastoplastic models without damage, the predictions from the proposed model is in better agreement with the experiments, and can better capture the rate-dependency in creep responses of asphalt mastic especially below its softening point of 47 ℃ 展开更多
关键词 asphalt mastic visco-elastoplastic damage model compressive creep
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Henriksen and Flora (1999) Revisited A Literature Review on Third-Person Effects and Children/Adolescents*
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作者 Gabriella Sandstig 《Journal of Literature and Art Studies》 2013年第7期436-450,共15页
In this literature review on TPE (third-person effects) and the behavioral consequences on children, the research questions posed are how the body of knowledge has evolved since the first empirical evidence of TPE a... In this literature review on TPE (third-person effects) and the behavioral consequences on children, the research questions posed are how the body of knowledge has evolved since the first empirical evidence of TPE among children and what knowledge gaps that remain. The traceable developments are two: (1) Compared to the vast amount of articles on TPE in general, the 5 9 identified on the topic of children are few and two thirds actually focus on adolescents/young adults rather than children. The reason put forward for studying younger children is the urge to prevent risky behavior through media literacy programs or pro-social advertisements; and (2) The studies have not primarily addressed results to support occurrence of TPE among children. Rather they support parental TPE or among the adolescents that TPE and reverse TPE occur due to certain kind of media content. The discussion on knowledge gaps that remain follow three themes: (1) Differentiations between self and others are in psychological studies implied to occur among children between the ages of 3-4 years old, yet no study address how children develop TPE; (2) There is a tendency to follow the more general development within TPE research with the renewed interest in behavioral consequences. But the primary behavioral consequence studied in TPE in general and within studies of TPE and children is support for censorship. Few studies address "real" behavioral consequences like parental mediation; and (3) There is also a need for more theoretically coherent research on the importance of social distance. 展开更多
关键词 third-person perception TPE (third-person effects) hypothesis TPE (third-person effects) CHILDREN social distance corollary
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火焰复合层对化学交联聚乙烯发泡材料力学性能的影响 被引量:2
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作者 张伯琴 孟积兴 +2 位作者 张俊平 龙国荣 胥明 《实验力学》 CSCD 北大核心 2018年第3期377-384,共8页
化学交联聚乙烯发泡材料(Cross-linked polyethylene,XPE)具有优异的物理、化学与力学性能,被广泛应用于工业领域。本文通过对不同层数的XPE发泡材料进行加载-卸载试验与压缩循环试验,得到不同层数XPE发泡材料的应力-应变曲线,获得了... 化学交联聚乙烯发泡材料(Cross-linked polyethylene,XPE)具有优异的物理、化学与力学性能,被广泛应用于工业领域。本文通过对不同层数的XPE发泡材料进行加载-卸载试验与压缩循环试验,得到不同层数XPE发泡材料的应力-应变曲线,获得了弹性区与平台区分界点的应力与应变、平台区与强化区应力的数量关系。通过计算得出应力-应变环的面积,发现其能量耗散能力随加载次数增加呈现下降趋势。结果表明,单层XPE发泡材料的弹性区与平台区弹性极限应变、临界应力强度和应力环面积等性质与多层材料相比差别显著,而多层材料间力学性能的差异微小。这些特征表明,火焰复合层自身具有较大的刚度并对发泡材料孔壁有较强的约束,改善了XPE发泡材料的刚度、弹性模量及耗能能力等。 展开更多
关键词 XPE发泡材料 火焰复合层 加载-卸载试验 应力-应变曲线 弹塑性行为
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Elastoplastic damage model for concrete based on consistent free energy potential 被引量:4
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作者 ZHANG Ji LI Jie 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第11期2278-2286,共9页
The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic ener... The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic energy storage rates is proposed, which are conjugate forces of hardening variables in an undamaged configuration. Then an analogy between the evolution of harden- ing variables and that of a plastic strain is used to postulate the formulation of plastic free energy. This formulation reflects the specific characteristics of a certain plasticity model, so it can serve well as a thermodynamic link between plasticity and dam- age. By combination of the general formulation of free energy with the double hardening plasticity theory and two-parameter damage expression, a thermodynamically well-founded elastoplastic damage model for concrete is constructed. The operator split algorithm is emploved, and the numerical simulations a^ree well with a series of material tests. 展开更多
关键词 free energy plastic energy storage damage energy release constitutive model CONCRETE
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Viscoelastic plastic continuous physical model of a magnetorheological damper applied in the high speed train 被引量:1
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作者 LI ZhongJi NI Yi-Qing +1 位作者 DAI HuanYun YE ShuQin 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第10期2433-2446,共14页
In the preliminary design stage of high-speed train smart suspension,a simple,yet accurate magnetorheological(MR)damper model whose parameters have clear physical meaning is needed.Based on the working mechanism analy... In the preliminary design stage of high-speed train smart suspension,a simple,yet accurate magnetorheological(MR)damper model whose parameters have clear physical meaning is needed.Based on the working mechanism analysis and the dynamic behavior study of the MR damper,a new consecutive viscoelastic plastics(VEP)model is proposed.A methodology to find the parameters of the proposed model directly has been proposed.The comparison with experimental results indicates that the proposed model could adequately characterize the intrinsic nonlinear behavior of the MR damper,including the hysteretic behavior,roll-off phenomenon,and the variation of the hysteresis width in terms of the frequency and magnitude of excitation.The results of experimental testing prove that the accuracy of the proposed model is higher than that of the phenomenological model while only containing four undetermined parameters with clear physical meaning.Moreover,based on the proposed VEP model,a nonlinear stiffness VEP(nkVEP)model is developed with higher precision in the hysteretic region.The nkVEP model,which can reproduce the behavior of the damper with fluctuating input current,is developed.The proposed model could predict accurately the response of the MR damper in a wide range of frequency and displacement. 展开更多
关键词 magnetorheological (MR) damper physical model viscoelastic plastics (VEP) model nonlinear stiffness VEP (nkVEP)model parameters identification
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Modeling of strength and deformation of overconsolidated clays based on bounding surface plasticity 被引量:1
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作者 XIAO Yang LIU HanLong +1 位作者 SUN YiFei LIU Hong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第9期1452-1462,共11页
An elastoplastic constitutive model for overconsolidated clays is established in the framework of the critical state theory and bounding surface plasticity theory. The bounding surface is defined as the maximum yield ... An elastoplastic constitutive model for overconsolidated clays is established in the framework of the critical state theory and bounding surface plasticity theory. The bounding surface is defined as the maximum yield surface in the loading history. A yielding ratio, i.e., an internal variant, is defined as the size ratio of the current yield surface to the corresponding bounding surface. The yielding ratio instead of the overconsolidation ratio(OCR) is used to evaluate the strength and stress-strain behaviors of overconsolidated clays in the shearing process. The bounding stress ratio incorporating the effect of the yielding ratio is used to characterize the potential failure strength of the overconsolidated clays. The dilation stress ratio taking into account the effect of the yielding ratio is applied to describe the dilatancy behaviors of the overconsolidated clays. Comparisons between model predictions and test data show that the proposed model could well capture the strength and stress-strain behaviors of normally consolidated and overconsolidated clays. 展开更多
关键词 overconsolidated clay overconsolidated ratio critical state theory yielding ratio peak state strength DILATANCY
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A physical mechanism based investigation on the elasto-plastic-damage behavior of anisotropic aluminum alloys under finite deformation
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作者 CHEN Cen LIANG NaiGang +1 位作者 LIU Fang FU Qiang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第3期400-410,共11页
The elasto-plastic-damage behavior of anisotropic aluminum alloys is investigated under finite deformation using a physical mechanism based constitutive model.With an application to the structural calculation,the pres... The elasto-plastic-damage behavior of anisotropic aluminum alloys is investigated under finite deformation using a physical mechanism based constitutive model.With an application to the structural calculation,the present model is used to describe and analyze the mechanical response of anisotropic 6260-T6 aluminum alloy extrusions.For the tensile specimens extracted along three different material orientations from the extruded aluminum profile,twelve simulations are carried out covering four different specimen geometries.The simulation results in force-displacement response and central logarithmic axial strain evolution are compared with experimental results.From the comparisons,it can be concluded that the present model has the capacity to describe the behavior of anisotropic material.From the force-displacement curves,the anisotropy is observed in different material orientations,and the physical mechanism of anisotropy is analyzed. 展开更多
关键词 elasto-plastic-damage behavior ANISOTROPY physical mechanism finite deformation constitutive theory componentassembling model
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