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1.
基于Mooney-Rivlin模型和Yeoh模型2种橡胶本构模型,建立了硅橡胶、丁腈橡胶和氟橡胶的单轴压缩实验有限元模型,对比了3种橡胶材料的名义应力-应变曲线及模拟仿真。结果表明,Mooney-Rivlin模型适合橡胶的小变形行为,Yeoh模型适合橡胶的大变形行为,且Yeoh模型在橡胶小变形时也具有较好的拟合度。  相似文献   

2.
闫昱全  宋国臣 《橡胶科技》2023,21(7):0325-0329
基于橡胶试样单轴拉伸试验得到的拉力和变形量等试验数据,利用最小二乘法拟合求得橡胶材料的Mooney-Rivlin模型及Yeoh模型常数。基于有限元方法,用得到的模型常数对试样变形量进行计算并与试验结果对比。结果表明,Mooney-Rivlin模型在小应变和中等应变时可以较好地描述材料的力学行为,Yeoh模型适合模拟大应变时材料的力学行为。利用得到的模型常数计算分析异形密封圈的静态性能,最大变形量计算值与试验值的相对误差为2.74%,表明了所选模型常数的准确性。  相似文献   

3.
李昊  肖光辉  贺才春  涂奉臣 《橡胶工业》2020,67(7):0529-0533
分别采用Mooney-Rivlin,Odgen和Yeoh橡胶材料本构模型对永磁同步直驱系统用弹性联轴器进行有限元建模和径向刚度仿真计算,并将仿真计算结果与试验结果进行对比。分析得出,采用Mooney-Rivlin和Odgen模型得到的弹性联轴器径向刚度与试验值偏差较大,采用能够模拟大变形的Yeoh模型得到的弹性联轴器径向刚度与试验值偏差较小,Yeoh模型适合用于弹性联轴器及同类产品进行力学性能分析。  相似文献   

4.
通过对油浸式电抗器器身-油箱间阻尼橡胶材料进行轴向压缩滞回性能试验,研究了其阻尼特性;依据实验数据并结合ABAQUS数值模拟结果,校正了适用于油浸式电抗器器身-油箱间阻尼橡胶材料的Mooney-Rivlin和Yeoh本构模型参数。结果表明,相比普通抗振橡胶试件,丁腈橡胶试件的轴向压缩刚度更大,滞回曲线更饱满,耗能能力更强;Mooney-Rivlin模型和Yeoh模型均适用于NBR试件的小变形和大变形行为,其中Mooney-Rivlin模型参数和Yeoh模型参数计算结果最大误差分别为-11.31%和-12.21%。  相似文献   

5.
超弹性本构模型在轮胎有限元分析中的应用   总被引:6,自引:3,他引:3  
王友善  王锋  王浩 《轮胎工业》2009,29(5):277-282
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.  相似文献   

6.
基于Mooney-Rivlin和Yeoh模型的超弹性橡胶材料有限元分析   总被引:4,自引:0,他引:4  
通过介绍橡胶材料两种常见的应变能密度模型--Mooney-Rivlin模型和Yeoh模型,解析求得其材料常数,并结合ansys有限元分析软件,比较两种模型的位移、应力云图,验证了它们的适用范围,对超弹性材料的有限元分析模型选用的总结,为这类材料的有限元分析和应用起到了指导作用.  相似文献   

7.
付新华  李宁  郭渊浩  李鹏 《轮胎工业》2020,40(1):0056-0061
选取某规格全钢子午线轮胎胶料分别进行单轴拉伸、等双轴拉伸和平面拉伸不同变形模式测试,分析比较不同变形模式组合时Yeoh,Ogden和Van der Waals等本构模型的拟合精度,并以同规格轮胎为例对比不同变形模式下本构模型的仿真精度。结果表明,当仅有单轴拉伸数据时适宜选择Yeoh模型,而3种变形模式结合使用能够更好地表征胶料在工作状态时的变形状态。  相似文献   

8.
橡胶类超弹性本构模型中材料参数的确定   总被引:2,自引:0,他引:2       下载免费PDF全文
燕山  王伟 《橡胶工业》2014,61(8):453-457
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。  相似文献   

9.
顾铖璋 《橡胶科技》2021,19(8):0375-0381
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。  相似文献   

10.
针对适用于板式支座的新型三元乙丙橡胶(EPDM)材料进行单轴拉伸试验研究,分析3种超弹性唯像本构模型对新型改性EPDM材料的适用性。结果表明,Yeoh模型拟合效果最好,获取相应的材料参数并建立与EPDM标准试样对应的有限元分析模型,有限元数值模拟数据与试验数据基本吻合,对EPDM板式支座数值模拟的研究具有借鉴意义。  相似文献   

11.
Herman P. Ruyter 《Fuel》1982,61(12):1182-1187
A series of low-rank materials, ranging from biomass waste to subbituminous coal, were subjected to hydrothermal coalification, i.e. heat treatment in an autoclave with water. The results, together with relevant literature data, cover a wide range of reaction conditions: temperatures from 120° to 390° and residence periods from 1 min to 6 months. Using overall kinetics, the progress of hydrothermal coalification in terms of the evolution of carbon dioxide as a function of the conditions has been expressed in a simple model. Low-rank materials can be described in terms of properties that can be gathered into general relations which hold over wide ranges. Over the range from biomass to subbituminous coal, where coalification mainly implies the evolution of water and carbon dioxide, the conversion model allows the prediction of the enrichment of a material on the basis of feedstock properties and the conditions applied.  相似文献   

12.
Standard variable selection procedures, primarily developed for the construction of outcome prediction models, are routinely applied when assessing exposure effects in observational studies. We argue that this tradition is sub-optimal and prone to yield bias in exposure effect estimators as well as their corresponding uncertainty estimators. We weigh the pros and cons of confounder-selection procedures and propose a procedure directly targeting the quality of the exposure effect estimator. We further demonstrate that certain strategies for inferring causal effects have the desirable features (a) of producing (approximately) valid confidence intervals, even when the confounder-selection process is ignored, and (b) of being robust against certain forms of misspecification of the association of confounders with both exposure and outcome.  相似文献   

13.
从区间模型预测控制到双层结构模型预测控制   总被引:2,自引:2,他引:0       下载免费PDF全文
邹涛  王丁丁  潘昊  苑明哲  季忠宛 《化工学报》2013,64(12):4474-4483
模型预测控制算法(MPC)存在设定点控制与区间控制两种策略,区间预测控制较之设定点控制在技术上具有先进性。目前,主流的预测控制软件技术均采用双层结构,即上层稳态优化计算最优设定点,下层动态控制负责动态跟踪最优设定点。从过程稳态的角度出发,分别对区间预测控制和双层结构预测控制进行了机理分析,从定性与定量两个方面比较了这两者的异同点,提出并证明了两者的一致性条件。论述了双层结构预测控制较之单层结构下的区间控制更具先进性。  相似文献   

14.
Determining good parameter estimates in (exponential smooth transition autoregressive) models is known to be difficult. We show that the phenomena of getting strongly biased estimators is a consequence of the so‐called identification problem, the problem of properly distinguishing the transition function in relation to extreme parameter combinations. This happens in particular for either very small or very large values of the error term variance. Furthermore, we introduce a new alternative model – the TSTAR model – which has similar properties as the ESTAR model but reduces the effects of the identification problem. We also derive a linearity and a unit root test for this model.  相似文献   

15.
Pyromellitic dianhydride was reacted with various substituted aryl amines, under conditions similar to those used for polyimide formation. Yields of model imides have been greatly improved over those found in previous studies. The work has shown that the major impurities formed when the reactions were performed in solutions of N,N-dimethylformamide or N,N-dimethylacetamide were adducts containing chemically bound solvent residues.  相似文献   

16.
17.
龙桑田 《国外塑料》2004,22(6):88-88
德国多媒体艺术家Andre Heller为2006年德国世界杯足球赛创作了一件特殊的艺术品,就是将足球与艺术结合在一个巨大的足球模型上。这个巨型足球高20米,最近已在德国正式展出。这个巨型足球外层是用Dyneon公司出品的乙烯一四氟乙烯共聚物(ETFE)制成,这种高性能塑料也常用作现代的轻质屋顶结构材料。巨型足球模型的展出,是德国政府和大赛组委会作为宣传2006年德国世界杯足球赛而组织的一项文化与艺术活动序幕。  相似文献   

18.
The purpose of this article is to develop the likelihood ratio test for the structural change of an AR model to a threshold AR model. It is shown that the log‐likelihood ratio test converges to the maxima of a two‐parameter Gaussian process in distribution. This limiting distribution is novel and we tabulate the critical values. Some simulations are carried out to examine the finite‐sample performance of this test statistic. This article also includes a weak convergence of a two‐parameter marked empirical process, which is of independent interest.  相似文献   

19.
Models fitted to data are used extensively in chemical engineering for a variety of purposes, including simulation, design and control. In any of these contexts it is important to assess the uncertainties in the estimated parameters and in any functions of these parameters, including predictions from the fitted model. Profiling is a likelihood ratio approach to estimating uncertainties in parameters and functions of parameters. A comparison is made between the optimization and reparameterization approaches to determining likelihood intervals for functions of parameters. The merits and limitations of generalized profiling are discussed in relation to the linearization approach commonly used in engineering. The benefits of generalized profiling are illustrated with two examples. A geometric interpretation of profiling is used to elucidate its value, and cases are identified for which the numerical algorithm fails. An alternative approach is suggested for these cases.  相似文献   

20.
刘昌明  陈亚琦  王志刚 《耐火材料》2020,54(2):103-106,111
耐火材料的本构关系模型是材料对外载荷所作变形响应的一种数学表达,是数值模拟准确性与否的基础。为此,在细观损伤力学模型多尺度特性的基础上,借助商业有限元软件的二次开发功能,通过编制用户子程序接口将其界面细观力学模型的损伤本构关系嵌入到软件中,首先在宏观尺度上对炉衬结构耐火材料进行了拉、压加载数值试验,数值模拟的结果可以与试验结果较好地吻合;之后借助代表体积RVE单元,采用不同灰度代表不同损伤状态,在微观尺度上对损伤进行了直观表征,成功实现了炉衬结构耐火材料的多尺度模拟。  相似文献   

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