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髌骨软骨拉伸应力松弛蠕变实验研究 被引量:3
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作者 孟广伟 程杰平 马洪顺 《医用生物力学》 EI CAS CSCD 2003年第4期239-243,255,共6页
目的 研究正常国人 8具新鲜尸体髌骨软骨的力学性质 ,为临床提供生物力学参数。方法 对正常国人新鲜尸体髌骨软骨一维拉伸力学性能和拉伸应力松弛、蠕变粘弹性力学性质进行实验研究。结果 获得了髌骨软骨一维拉伸的破坏载荷、伸长比... 目的 研究正常国人 8具新鲜尸体髌骨软骨的力学性质 ,为临床提供生物力学参数。方法 对正常国人新鲜尸体髌骨软骨一维拉伸力学性能和拉伸应力松弛、蠕变粘弹性力学性质进行实验研究。结果 获得了髌骨软骨一维拉伸的破坏载荷、伸长比、张应力、张应变等测试结果 ,以多项式用最小二乘法对拉伸实验数据进行拟合 ,得出了半月板的应力 -应变关系表达式和应力 -应变曲线。还得出了应力松弛、蠕变数据、曲线和归一化应力松弛函数、归一化蠕变函数数据、曲线。对实验数据以最小二乘法进行处理 ,得出了G(t)表达式 ,根据准线性理论得出了半月板的松弛函数K(λ、t)=G(t)T(e) (λ)的表达式。结论 髌骨软骨单向拉伸最大载荷为 3 8.5 4± 4.1 8N ,伸长比为 1 .3 1 2± 0 .0 1 8,张应力为 6.65± 0 .83MPa ,应变为 3 4.0± 3 .6%。应力松弛曲线是以对数关系变化的 。 展开更多
关键词 髌骨软骨 应力松弛蠕变 单向拉伸 松弛函数
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腰椎L_4松质骨应力松弛蠕变方程 被引量:37
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作者 孙树东 赵长福 马洪顺 《生物医学工程研究》 2007年第2期128-130,134,共4页
研究正常国人新鲜尸体腰椎L 4椎体松质骨的粘弹性力学性质,为临床提供生物力学参数。在Shimadzu AUTOGRAPH电子万能试验机上,对L4椎体松质骨试样进行应力松弛蠕变实验。得出了L4椎体应力松弛蠕变曲线,以三参数模型处理实验数据,得出应... 研究正常国人新鲜尸体腰椎L 4椎体松质骨的粘弹性力学性质,为临床提供生物力学参数。在Shimadzu AUTOGRAPH电子万能试验机上,对L4椎体松质骨试样进行应力松弛蠕变实验。得出了L4椎体应力松弛蠕变曲线,以三参数模型处理实验数据,得出应力松弛蠕变方程。结果表明:L4椎体7200s,应力松弛量为0.232MPa、蠕变量为0.271%。 展开更多
关键词 脊柱 腰椎 松质骨 应力松弛蠕变方程
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金属波齿柔性石墨复合垫片蠕变-应力松弛性能研究 被引量:2
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作者 郭滨诗 姜敏夫 刘金义 《化工科技》 CAS 2013年第4期58-60,共3页
垫片的蠕变-应力松弛特性对螺栓法兰密封连接系统的可靠性有显著的影响。作者按照GB/T19066.3的实验条件对标准规格为D65.5mm×50.5mm×2.5mm 3种不同几何尺寸的金属(06Cr19Ni10+柔性石墨)波齿复合垫片进行蠕变-应力松弛实验研... 垫片的蠕变-应力松弛特性对螺栓法兰密封连接系统的可靠性有显著的影响。作者按照GB/T19066.3的实验条件对标准规格为D65.5mm×50.5mm×2.5mm 3种不同几何尺寸的金属(06Cr19Ni10+柔性石墨)波齿复合垫片进行蠕变-应力松弛实验研究,从而找出应力松弛特性影响因素及其规律,为工程实践提供科学指导。 展开更多
关键词 金属波齿 柔性石墨 垫片 蠕变-应力松弛
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剑麻纤维素微晶/酚醛树脂力学性能和动态力学性能的研究 被引量:2
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作者 黄绍军 韦春 +2 位作者 刘红霞 吕建 曾思华 《现代塑料加工应用》 CAS 北大核心 2013年第1期1-4,共4页
采用硅烷偶联剂KH550对从剑麻中提取的剑麻纤维素微晶(SFCM)进行改性,对SFCM与酚醛树脂(PF)进行熔融共混、用模压成型工艺制备SCFM/PF复合材料,研究SFCM含量对复合材料的力学性能、动态力学性能、蠕变和应力松弛性能的影响。结果表明,... 采用硅烷偶联剂KH550对从剑麻中提取的剑麻纤维素微晶(SFCM)进行改性,对SFCM与酚醛树脂(PF)进行熔融共混、用模压成型工艺制备SCFM/PF复合材料,研究SFCM含量对复合材料的力学性能、动态力学性能、蠕变和应力松弛性能的影响。结果表明,与PF相比,SFCM/PF复合材料的冲击强度和弯曲强度分别提高了54.94%,31.37%,储能模量提高了30%,玻璃化转变温度提高了41℃,蠕变和应力松弛性能也得到了提高。 展开更多
关键词 剑麻纤维素微晶 酚醛树脂 复合材料 力学性能 动态力学性能 蠕变应力松弛
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Correlation of Cooperatively Localized Rearrangement on the "Fluidized Domain" of Polymers to Their Nonexponentially Viscoelastic Behaviors at Double Aging Processes (I): A Set of Reduced Universal Equations on the Stress Relaxation Modulus and Creep Comp
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作者 刘颖 宋名实 +2 位作者 金艳 胡桂贤 吴大鸣 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第1期45-64,I0001,共21页
Based on the structure of glass (or liquid) polymers consisting of α-domain, β-co-domain, and entanglement constituent chain networks, and the nonexponentially viscoelastic behavior, a “heterophase fluctuation” ... Based on the structure of glass (or liquid) polymers consisting of α-domain, β-co-domain, and entanglement constituent chain networks, and the nonexponentially viscoelastic behavior, a “heterophase fluctuation” model was proposed. It was found that the dynamics of cooperative rearrangement on the “fluidized domain” has a great shear rate, domain size, and temperature dependences. When the shear rate, domain size, and temperature dependences were taken account into the cooperatively localized rearrangement on the fluidized domain by the degradation of primary α-domain and the reformation of secondary β-co-domain constituent chains. A new dynamic theory of cooperatively localized rearrangement on the fluidized domain constituent chains with different size and different network chain length during physical and mechanical aging was established. The total viscoelastic free en-ergy of deformation resulting from the change in conformations of α-domain, β-co-domain, crytallite, crosslinked, and trapped entanglement constituent chains during aging processes was calculated by the combining method of kinetics and statistical mechanics. The constitu- tive equations and reduced stress relaxation modulus and creep compliances for three types of polymers were also derived. Finally, two reduced universal equations on creep compliance and stress relaxation modulus with a non-linear and two nonexponential parameters α and β were theoretically derived from the dynamic theory and a statistically extended mode coupling theory for double aging effects of polymers was developed. Results show that the two reduced universal equations have the same form as Kohlraush-Williams-Watts (K-W-W) stretched exponential function. The nonlinearity and the nonexponentiality are, respectively, originated from the memory effects of nonthermal and thermal history. The correlation of nonlinearity, α and β to the aging time, aging temperature, and the mesomorphic structure of fluidized domains was also established. 展开更多
关键词 Heterophrase fluctuation model Kinetics of aging Dynamics of de-aging Creep and stress relaxation K-W-W decay function Fluidized domain constituent chain
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中等时间尺度下弹道明胶的线性黏弹性模型
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作者 马小林 范毓润 《高分子材料科学与工程》 EI CAS CSCD 北大核心 2018年第12期95-100,共6页
在不同时间尺度下,明胶表现出不同的黏弹性行为。应用蠕变和应力松弛模式研究质量分数为10%的弹道明胶在中等时间尺度下的线性黏弹性行为。低剪切速率下的连续加载-卸载实验显示,在常规感知的时间尺度下(~1min)弹道明胶接近完全弹性体... 在不同时间尺度下,明胶表现出不同的黏弹性行为。应用蠕变和应力松弛模式研究质量分数为10%的弹道明胶在中等时间尺度下的线性黏弹性行为。低剪切速率下的连续加载-卸载实验显示,在常规感知的时间尺度下(~1min)弹道明胶接近完全弹性体,其线性区应变范围为0~0.25。对蠕变实验对应的中等时间尺度(>1h),选择样品老化24h作为实验起点,这时明胶结构缓慢老化带来的影响可以忽略,从而能够构建恒定参数的本构方程来描述弹道明胶的线性黏弹性行为。对1组蠕变实验结果进行分析,可确定Burgers模型的4个粘弹性参数,然后使用该组参数的模型预测另外2组蠕变实验以及应力松弛实验。结果表明Burgers模型能较好地表征弹道明胶在中等时间尺度下的线性黏弹性行为。 展开更多
关键词 弹道明胶 老化行为 中等时间尺度 线性黏弹性 BURGERS模型 蠕变应力松弛
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Correlation of Cooperatively Localized Rearrangement on the "Fluidized Domain" of Polymers to Their Nonexponentially Viscoelastic Behavior and Lifetime at Double Aging Processes II: Estimation of Long-term Mechanical Behavior and Lifetime of Polymeric Materials from Short-time Creep and Stress Relaxation Tests 被引量:1
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作者 金艳 宋名实 +1 位作者 胡桂贤 吴大鸣 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第2期185-194,I0002,共11页
Three kinds of polymeric materials are taken as example for the verification of linear ex-trapolation method from unified master lines with reduced universal equations on creep and stress relaxation tests. The theoret... Three kinds of polymeric materials are taken as example for the verification of linear ex-trapolation method from unified master lines with reduced universal equations on creep and stress relaxation tests. The theoretical values of long-term mechanical behavior and lifetime for a cured epoxide, polypropylene, poly(methyl-methacrylate), and SBR rubber are directly evaluated with the universal equations on reduced creep compliance and reduced stress relax-ation modulus and are compared with their predicted values by the linear extrapolation from the unified master lines of creep and stress relaxation. The results show that the theoretical values of dimensional stability, bearing ability and lifetime are in an excellent agreement with the predicted values, it shows that the linear extrapolation method is more simple and reliable. The dependences of long-term mechanical behaviors and lifetime on the different aging times are discussed. 展开更多
关键词 Physical aging Mechanical aging Dimensional stability Bearing ability Creep and stress relaxation Estimation of aging lifetime
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Uniqueness of rate-dependency, creep and stress relaxation behaviors for soft clays 被引量:1
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作者 朱启银 尹振宇 +2 位作者 徐长节 殷建华 夏小和 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期296-302,共7页
This work focuses on the uniqueness of rate-dependency, creep and stress relaxation behaviors for soft clays under one-dimensional condition. An elasto-viscoplastic model is briefly introduced based on the rate-depend... This work focuses on the uniqueness of rate-dependency, creep and stress relaxation behaviors for soft clays under one-dimensional condition. An elasto-viscoplastic model is briefly introduced based on the rate-dependency of preconsolidation pressure. By comparing the rate-dependency formulation with the creep based formulation, the relationship between rate-dependency and creep behaviors is firstly described. The rate-dependency based formulation is then extended to derive an analytical solution for the stress relaxation behavior with defining a stress relaxation coefficient. Based on this, the relationship between the rate-dependency coefficient and the stress relaxation coefficient is derived. Therefore, the uniqueness between behaviors of rate-dependency, creep and stress relaxation with their key parameters is obtained. The uniqueness is finally validated by comparing the simulated rate-dependency of preconsolidation pressure, the estimated values of secondary compression coefficient and simulations of stress relaxation tests with test results on both reconstituted Illite and Berthierville clay. 展开更多
关键词 soft clays creep rate-dependency stress relaxation oedometer test
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橡胶弹性元件常见的几种失效形式
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作者 胡新颖 戴连鹏 隋青春 《中文科技期刊数据库(全文版)工程技术》 2021年第9期130-131,134,共3页
橡胶和塑料及纤维是典型的三大合成高分子材料,它具有高弹性,透气性,耐化学介质及电绝缘性能的优点。橡胶的这些基本性能使它在减震、密封、耐磨、防腐、绝缘等领域发挥越来越重要的作用。根据橡胶弹性元件的使用功能及失效特点,文中详... 橡胶和塑料及纤维是典型的三大合成高分子材料,它具有高弹性,透气性,耐化学介质及电绝缘性能的优点。橡胶的这些基本性能使它在减震、密封、耐磨、防腐、绝缘等领域发挥越来越重要的作用。根据橡胶弹性元件的使用功能及失效特点,文中详细介绍橡胶弹性元件最常见的几种的失效形式,以及失效后对产品性能使用的影响。 展开更多
关键词 橡胶弹性元件 应力松弛蠕变失效 刚度失效 稳定性失效 疲劳失效
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Experimental Study on Stress Relaxation and Creep Properties of Human Thoracolumbar Vertebral Bodies and Intervertebral Discs
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作者 HUANG Jian-song HUA Hong-xing +1 位作者 WANG Yi-jin CHEN Yong 《Chinese Journal of Biomedical Engineering(English Edition)》 2009年第4期154-161,共8页
Objective:Underwater shock can produce extremely high accelerations, resulting in severe human injuries on shipboard, and human thoraco lumbar spines are prone to suffer from injuries by ship shock motion. To observe ... Objective:Underwater shock can produce extremely high accelerations, resulting in severe human injuries on shipboard, and human thoraco lumbar spines are prone to suffer from injuries by ship shock motion. To observe the viscoelasticity of thoracolumbar of young fresh cadavers, and to provide biomechanical parameters for both research and clinical practice. Materials and Methods:5 fresh young male cadavers (aged 22 to 31 years) were provided, and 15 thoracolumbar spinal anatomies of 5 samples were harvested within 1 hour of death. WE-10A universal testing machine was used for creep and relaxation tests.Results:Stress relaxation and creep deformation equations are derived from the biomechanics model and the measured and simulated curves are compared. The creep in vertebral bodies and intervertebral discs exhibited significantly changes in the first 5 min and 10 min, respectively. The stress rapidly decreased in the first 2 min, and then gradually went balance during the relaxation process. Conclusion:The change in creep rate is significant at early stage,and gradually slows down.This indicates that the differences between internal pressure and local pressure are decreased until balance. The simulated curve derived from equation coincides with the experimental data to a large degree, which states that the equation is rational and reliable. 展开更多
关键词 spine biomechanics functional spinal unit (FSU) vertebral body intervertebral disc stress relaxation creep deformation spring-dashpot
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