WH型橡胶隔振器静刚度仿真研究

以WH型橡胶隔振器为研究对象，基于超弹性本构理论，应用Abaqus软件建立橡胶隔振器的有限元模型，计算WH型橡胶隔振器的三向静刚度，并与测试结果进行对比。结果表明：对于WH型橡胶隔振器，横向静刚度的计算应选择单轴拉伸＋等双轴拉伸的应力-应变曲线组合，垂向、纵向静刚度的计算应选择单轴拉伸＋平面拉伸的应力-应变曲线组合；本研究探讨的5种超弹性本构模型中，Mooney-Rivlin模型的计算误差最小，Neo Hooke模型仅在描述剪切变形时精度较高，Ogden模型、Yeoh模型和Van Der Waals模型的计算误差较大。     

超弹性本构模型在轮胎有限元分析中的应用

对3种主要的超弹性本构模型进行对比,并基于非线性力学理论对轮胎用橡胶材料单轴拉伸力学行为进行测试;假设橡胶为完全不可压缩材料,给出Neo-Hookean,Mooney-Rivlin和Yeoh 3种超弹性本构模型常数的确定方法;在Ansys软件中采用不同的本构模型对轮胎充气状态的力学性能进行分析.结果表明,在轮胎小变形条件下,线弹性模型的模拟结果与实测值比较吻合.     

高阻尼橡胶支座的本构模型研究综述

从弹塑性和超弹性两方面进行了高阻尼橡胶本构理论的推导,综述并对比分析了普通橡胶材料分别基于热力学统计和唯象学建立的常用超弹性本构模型,并以普通橡胶材料本构模型为基础,考虑高阻尼橡胶在大变形下的强化、应变历史相关性以及速度相关性,总结了目前较能精确模拟高阻尼橡胶支座受力特性的几种本构模型,以期为高阻尼橡胶支座的力学性能研究提供理论参考和依据。     

橡胶类超弹性本构模型中材料参数的确定

采用单轴拉伸、等双轴拉伸及平面剪切下橡胶材料试验数据的4种不同组合方式分别对主要用于表述橡胶超弹性的Yeoh模型和Ogden三阶模型进行拟合,并得出两种模型的材料参数。建立单轴拉伸、等双轴拉伸及平面剪切试验的有限元模型,探究1种仅仅借助单轴拉伸试验数据并结合其他2种试验有限元模型预测结果,进行橡胶类本构模型参数拟合的新方法。结果表明:选用Yeoh模型时,利用单轴拉伸和等双轴拉伸组合方式可获得较理想的材料参数;在只具备单轴拉伸试验数据的条件下,利用单轴试验数据和等双轴有限元模型预测数据的组合方式在低应变区用Yeoh模型拟合得到的材料参数较可靠;Ogden三阶模型较Yeoh模型精度高,但计算效率低且不易收敛。     

圆柱形橡胶试样压缩变形有限元分析的超弹性本构方程对比研究

采用有限元分析方法预测圆柱形橡胶试样的压缩变形,并与试验数据进行对比,判断不同本构方程的计算精度。结果表明:对于应力-应变试验,仅采用单轴拉伸(UT)试验数据拟合本构方程时,不能单纯依赖拟合精度判断本构方程的优劣;同时采用UT、平面拉伸(PT)和等双轴拉伸(ET)试验数据拟合本构方程时,整体计算精度大幅提升,且可依据拟合精度判断超弹性本构方程的优劣。对于超弹性本构方程,若提供UT,PT和ET试验数据,宜选用拟合精度高的O_Ni,P_Ni,VdW,Marlow等方程;而在仅有UT数据的情况下,则宜选用RP_Ni,AB,Marlow等方程。     

橡胶材料超弹性本构模型选取及参数确定概述

概述橡胶材料超弹性本构模型的选取及参数确定。橡胶材料超弹性本构模型选取取决于材料试验、有限元分析适应性和橡胶制品力学计算精度三方面,模型参数确定方法主要有基于简单材料试验的本构理论计算法、基于完整材料试验的数值拟合法、根据已有橡胶材料特性的识别法和先进材料参数试验法。基于完整材料试验的数值拟合法和先进材料参数试验法是确定橡胶材料超弹性本构模型参数的发展方向。     

高阻尼橡胶的动态压缩性能及其应变率相关的本构模型

为研究高阻尼橡胶的动态压缩性能及其应变率相关的本构模型,应用分离式Hopkinson压杆装置对高阻尼橡胶试样进行冲击压缩试验,获得了不同应变率下的应力-应变曲线。结果表明,高阻尼橡胶体现了明显的超弹性特征,在500/s到5 200/s的大应变率范围内,高阻尼橡胶具有明显的应变率相关性,相同应变条件下,应变率越高,应力值越大。考察几种常见超弹性本构模型对试验数据的拟合情况,并选取拟合最优的本构模型,拟合结果与试验结果非常吻合,研究结果为高阻尼橡胶在抗爆炸、抗冲击领域的进一步研究奠定了基础。     

橡胶材料的超弹性本构模型建模方法

正授权公告号:CN 105989244B授权公告日:2017年2月15日专利权人:中国人民解放军国防科学技术大学发明人:廖一寰、郝东、李东旭等本发明介绍了一种橡胶材料的超弹性本构模型建模方法。该方法首先提出聚合物分子链体积的影响模型;然后改进八链模型,提出拓扑约束所引起的概率密度函数;其后建立分子链的微观变形与宏观变形的关系,据此推导橡胶材料的应变能密度函数,得到非仿射超弹性本构模型。本发明在建立橡胶材     

隔振橡胶材料基于简单应变模式的 蠕变特性研究

对隔振橡胶材料的单轴拉伸应力松弛试验数据进行归一化处理,应用Prony级数模型对其应力松弛试验数据进行拟合,获得对应的粘弹本构参数。将表征粘弹特性的Prony级数因子引入Ogden超弹本构方程,获得隔振橡胶材料基于时间效应的本构方程,进而分析单轴拉伸、双轴拉伸和平面拉伸模式的蠕变特性,最后采用沙漏弹簧进行蠕变仿真与试验验证。该蠕变仿真预测方法为隔振橡胶材料的粘弹试验、蠕变计算和工程应用提供一种新思路。     

深冷环境下密封橡胶的力学性能研究

在深冷环境下密封橡胶易发生变脆、丧失高弹性等现象,从而导致密封性能降低。密封橡胶的力学性能是评估密封可靠性的重要参数。选择低苯基硅橡胶及以低苯基硅橡胶为基体分别添加全氟聚醚油和聚酰亚胺粉的改性橡胶为研究对象,考察3种橡胶在超低温下的力学性能,在常温(23℃)和超低温(-196℃)下进行单轴拉伸和压缩永久变形试验,并利用有限元软件Abaqus超弹性材料拟合板块对本构模型进行参数模拟,探讨Mooney-Rivlin模型、Ogden模型和Yeoh模型对超低温下密封橡胶的适用性。结果表明:在超低温下,聚酰亚胺粉改性低苯基硅橡胶的密封性能优于其他两种橡胶材料;在单轴拉伸试验拟合中,Yeoh模型拟合误差较小;在压缩试验拟合中,Mooney-Rivlin模型和Ogden模型能更准确地描述橡胶力学性能。     

Prediction of the nonlinear poisson function using large volumetric strains estimated from a finite hyperelastic material law

The aim of this study is to evaluate the transverse strain of hyperelastic solids as a function of its longitudinal using a special constitutive equation for compressible hyperelastic materials. In addition, the nonlinear dependence of the Poisson ratio on longitudinal strain was derived. Experimental data from EPDM elastomers subjected to uniaxial tension were used in order to determine the material parameters, which are incorporated in the constitutive law.     

Modeling of visco‐hyperelastic behavior of transversely isotropic functionally graded rubbers

In this article, visco‐hyperelastic constitutive model is developed to describe the rate‐dependent behavior of transversely isotropic functionally graded rubber‐like materials at finite deformations. Zener model that consists of Maxwell element parallel to a hyperelastic equilibrium spring is used in this article. Steady state response is described by equilibrium hyperelastic spring and rate‐dependence behavior is modeled by Maxwell element that consists of a hyperelastic intermediate spring and a nonlinear viscous damper. Modified and reinforced neo‐Hookean strain energy function is proposed for the two hyperelastic springs. The mechanical properties and material constants of strain energy function are graded along the axial direction based on exponential function. A history‐integral method has been used to develop a constitutive equation for modeling the behavior of the model. The applied history integral method is based on the Kaye‐BKZ theory. The material constant parameters appeared in the formulation have been determined with the aid of available uniaxial tensile experimental tests for a specific material and the results are compared to experimental results. It is then concluded that, the proposed constitutive equation is quite proficient in forecasting the behavior of rubber‐like materials in different deformation and wide ranges of strain rate. POLYM. ENG. SCI., 56:342–347, 2016. © 2016 Society of Plastics Engineers     

有限变形下的橡胶材料非线性高弹-粘弹性本构模型

本文基于唯象学原理提出了一种适用于橡胶材料在有限应变条件下的非线性高弹-粘弹性本构模型,该模型将应力拆分为两部分：第一部分基于Yeoh模型计算得到的高弹性应力;第二部分由Boltzmann叠加原理计算得到的带有率依赖性的粘弹性应力。该本构模型中应变依赖性的高弹性应力通过修正Zener模型中的非线性弹簧表示,时间及应变依赖性的粘弹性应力通过修正Zener模型中的非线性Maxwell模型表示。利用提出的高弹-粘弹性本构模型模拟不同应变条件下的拉伸、回复、应力松弛及多步松弛在内的复杂加载过程,并与实验值对比,结果表现出良好的吻合性,说明该本构模型的合理、可靠。     

A visco‐hyperelastic constitutive model to characterize both tensile and compressive behavior of rubber

The strain rate–dependent finite deformation behavior of three types of rubber under tension and compression are experimentally characterized using a Hopkinson bar. Based on the measured data, a frame‐independent incompressible visco‐hyperelastic constitutive equation is proposed to describe the tensile and compressive responses of rubber under high strain rates. The equation comprises two parts: a three‐parameter component based on an elastic strain energy potential, to characterize static hyperelastic behavior, and another with four parameters, developed from the BKZ model, to define rate sensitivity and strain history dependence. Established static and dynamic experimental techniques are employed to determine the seven parameters in the constitutive relationship. Comparison of predictions based on the proposed model with experiments shows that it is able to describe the visco‐hyperelastic behavior of rubber‐like materials under high strain rates. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 523–531, 2004     

New constitutive model for anisotropic hyperelastic biased woven fibre reinforced composite

Abstract

This paper presents an improved constitutive model having application in finite element analysis of composites made of hyperelastic matrix with biased woven fabric reinforcement and is based on a pragmatic approach and the continuum mechanics theory. A generalised strain energy function is developed via a series of uniaxial tests in fibre warp and weft directions and via shear tests of representative samples of composite fabric. The proposed material characterisation approach is demonstrated on composites made of neoprene rubber matrix with nylon biased woven reinforcements having volume fraction composition 0·74 vol.-% neoprene and 0·26 vol.-% nylon. The material parameters in the anisotropic hyperelastic model are obtained by minimisation of least square residuals of uniaxial and pure shear energy densities against the respective strain invariants. Numerical simulations of uniaxial and bulge tests of the composites using the material model presented in this paper are shown to correspond well with results obtained from laboratory experiment.     

Plastic behavior and deformation textures of poly(etherether ketone) under uniaxial tension and simple shear

Samples of poly(etherether ketone) (PEEK) were subjected to large plastic deformations under uniaxial tension and simple shear by means of a new video-controlled testing method at constant true strain rate. The “equivalent” stress-strain curves obtained under the two loading modes are close at the yield point, but diverge drastically at large strains, with a rapidly increasing hardening in tension and a moderate hardening under simple shear. X-ray diffraction goniometry shows that these contrasting behaviors are associated with the different textures developed in the crystallite orientations. Under tension, the PEEK lamellae are progressively tilted in such a way that the chain axis becomes oriented parallel to the tensile axis; in the other mode, the final chain orientation is near to the shear axis. DSC analyses of deformed samples in both modes are carried out. The results show that the tension loading induces a fragmentation of the thin lamellae, while the shear mode generates less fragmentation. A quantitative model is presented that involves a composite approach: (i) the viscoplastic deformation of the crystalline lamellae, which is controlled by chain slip and transverse slip systems on planes parallel to the c axis, and (ii) the hyperelastic deformation of the amorphous phase, which depends on the affine unfolding of statistically distributed subchains. A discussion of the influence of the CRSS values on the stress-strain curves and textures is developed by means of this model.     

The large strain compression,tension, and simple shear of polycarbonate

Polymeric materials subjected to large strains undergo an evolution in molecular orientation. The developing orientation and corresponding strengthening are highly dependent on the state of strain. In this paper, we examine and compare the very different stress-strain results of polycarbonate produced from four types of mechanical testing: uniaxial compression, plane strain compression, uniaxial tension, and simple shear. These tests produce different states of orientation within the material and, in the case of simple shear, the principle axes of orientation rotate during the deformation. The ability of the recent constitutive model of Arruda and Boyce (1992) to predict the to predict the observed behavior is evaluated. The model has been incoporated into a finite element code in order to properly simulate the material behavior during the inhomogenous deformations of tension (cold drawing) and simple shear. The material properties of the model are obtained from the uniaxial compression test and the model is then found to be truly predictive of the other states of deformation demonstrating its fully three dimensional capability. The disadvantages of the tensile and simple shear tests for obtaining the data needed to accurately quantify the large strain material behavior of polymers are shown and discussed.     

A phenomenological energy-based model to characterize stress-softening effect in elastomers

A phenomenological energy-based model for stress-softening of isotropic, incompressible hyperelastic rubberlike materials is derived here. In this model, the microstructural damage is characterized by an exponential softening function that depends on the current magnitude of the strain-energy function and its maximum previous value in a deformation of the virgin material. Theoretical models are presented for uniaxial, equibiaxial and pure shear deformations by using Gaussian and non-Gaussian material molecular network models. The accuracy of the resulting constitutive equations is demonstrated on uniaxial, equibiaxial and pure shear experimental data provided in the literature. Comparisons between the energy-based model and the strain intensity based phenomenological model described in [Elías-Zúñiga A, Beatty MF. ZAMP 2002;53:794-814. [1]] show that the model developed here is slightly superior in following experimental data.     

Cauchy stresses and vibration frequencies for the instability parameters of dielectric elastomer actuators

An analysis of the effect of Cauchy stresses, vibration frequency response, and instability on the transient dynamic response of step‐voltage‐driven dielectric elastomer actuators (DEAs) is presented in this paper. Material nonlinearities associated with the hyperelastic constitutive law are taken into account, and the membrane is assumed to be made of an isotropic, homogeneous, and incompressible material. The results for the neo‐Hookean material model are further extended to analyze relatively complex multiparameter hyperelastic models (Mooney–Rivlin and Ogden) that are often employed for investigating the behavior of DEAs. The dynamic instability parameters are predicted using energy‐based extraction of static instability and validated by the response of the material in the vicinity of the dynamic instability. The natural modes of the membrane are used to approximate the nonlinear deformation field using the Galerkin method. A detailed parametric analysis of the equations of motion for the prestretched membrane shows the natural frequencies and mode shapes of the membrane and the strong influence of the stretching ratios and material parameters on the linear and nonlinear oscillations of the membrane. The results of the present investigation show the electric field–frequency relations, resonance curves, and bifurcation diagrams using the nonlinear dynamics of DEAs subjected to electrical loads. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46215.     

Microstructure transformation and stress-strain behavior of isotactic polypropylene under large plastic deformation

The macroscopic stress-strain behavior of monoclinic polypropylene samples was investigated at 70°C under uniaxial tension and simple shear by means of a special videometric testing system that gives access to the constitutive equation of plastic behavior at constant strain rate up to large deformation. At several levels of plastic strain, the microstructural evolution of the material was characterized by means of X-ray scattering, densitometry and viscoelastic analysis. It appears that the strain hardening is high in tension, whereas it is nearly zero in shear. This behavior is associated with the development of a fiber texture in tension, which differs drastically from the planar crystalline texture developed in shear. Furthermore, it is shown that structural damage takes place as the plastic deformation proceeds in tension, while only little damage is recorded in shear. A viscoplastic model has been developed that specifically tales into account the various slip systems activated in the polypropylene crystallites and the elastic interactions of the lamellae through a self-consistent scheme. Simulations based on this model reproduce correctly the contrasting strain-hardening in tension and in shear and the different crystalline textures induced for these two loading paths.