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Numerical modeling of nonlinear deformation of polymer composites based on hyperelastic constitutive

Qingsheng YANG, Fang XU

《机械工程前沿(英文)》 2009年 第4卷 第3期   页码 284-288 doi: 10.1007/s11465-009-0067-0

摘要: Fiber reinforced polymer (FRP) composites exhibit nonlinear and hyperelastic characteristics under finite deformation. This paper investigates the macroscopic hyperelastic behavior of fiber reinforced polymer composites using a micromechanical model and finite deformation theory based on the hyperelastic constitutive law. The local stress and deformation of a representative volume element are calculated by the nonlinear finite element method. Then, an averaging procedure is used to find the homogenized stress and strain, and the macroscopic stress-strain curves are obtained. Numerical examples are given to demonstrate hyperelastic behavior and deformation of the composites, and the effects of the distribution pattern of fibers are also investigated to model the mechanical behavior of FRP composites.

关键词: composites     hyperelastic     finite deformation     homogenization     micromechanics    

Hypoplastic constitutive modeling of wetting deformation of weathered rockfill materials

Erich BAUER, Zhongzhi FU, Sihong LIU,

《结构与土木工程前沿(英文)》 2010年 第4卷 第1期   页码 78-91 doi: 10.1007/s11709-010-0011-8

摘要: The wetting deformation of weathered rockfill materials has been attracting growing attention from both engineers and scientists. The importance of realistic predictions of wetting deformations for high earth and rockfill dams is a strong motivation to establish a suitable constitutive model. Recently, the hypoplastic constitutive model by Gudehus and Bauer was extended by introducing solid hardness depending on the state of weathering. The extended model takes into account the influence of the current density, the effective stress state, the rate of deformation, and the time dependent process of degradation of the solid hardness. In the present paper, the performance of this model is evaluated by comparing numerical simulations with experiments obtained from a water sensitive rockfill material. In particular, triaxial compression paths and creep deformation under deviatoric stress states are considered. Finally, the constitutive model proposed is used to study the influence of a degradation of the solid hardness on the long term behavior of a hypothetical fill dam.

关键词: rockfill dams     weathered granular materials     hypoplasticity     solid hardness     creep     stress relaxation    

Development of a constitutive model for rockfills and similar granular materials based on the disturbed

Mehdi VEISKARAMI, Ali GHORBANI, Mohammadreza ALAVIPOUR

《结构与土木工程前沿(英文)》 2012年 第6卷 第4期   页码 365-378 doi: 10.1007/s11709-012-0178-2

摘要: Behavior of rockfills was investigated experimentally and theoretically. A series of standard triaxial compression tests were carried out on a quarried rockfill material at different stress levels. It was found that both the stress level and the shear stress ratio, like most of granular materials, controls the behavior of rockfill materials. At lower shear stress ratios the behavior is much more similar to a nonlinear elastic solid. When the shear stress goes further, the stress-strain curve shows an elasto-plastic behavior which suggests using the disturbed state concept to develop a constitutive model to predict the stress-strain behavior. The presented constitutive model complies reasonably with the experimental data.

关键词: constitutive model     granular material     rockfill     plasticity     disturbed state concept     stress level    

Precision glass molding: Toward an optimal fabrication of optical lenses

Liangchi ZHANG,Weidong LIU

《机械工程前沿(英文)》 2017年 第12卷 第1期   页码 3-17 doi: 10.1007/s11465-017-0408-3

摘要:

It is costly and time consuming to use machining processes, such as grinding, polishing and lapping, to produce optical glass lenses with complex features. Precision glass molding (PGM) has thus been developed to realize an efficient manufacture of such optical components in a single step. However, PGM faces various technical challenges. For example, a PGM process must be carried out within the super-cooled region of optical glass above its glass transition temperature, in which the material has an unstable non-equilibrium structure. Within a narrow window of allowable temperature variation, the glass viscosity can change from 105 to 1012 Pa·s due to the kinetic fragility of the super-cooled liquid. This makes a PGM process sensitive to its molding temperature. In addition, because of the structural relaxation in this temperature window, the atomic structure that governs the material properties is strongly dependent on time and thermal history. Such complexity often leads to residual stresses and shape distortion in a lens molded, causing unexpected changes in density and refractive index. This review will discuss some of the central issues in PGM processes and provide a method based on a manufacturing chain consideration from mold material selection, property and deformation characterization of optical glass to process optimization. The realization of such optimization is a necessary step for the Industry 4.0 of PGM.

关键词: precision glass molding     optical lens     constitutive modeling     optimization     manufacturing chain     Industry 4.0    

Damage-constitutive model for seawater coral concrete using different stirrup confinements subjected

《结构与土木工程前沿(英文)》 2023年 第17卷 第3期   页码 429-447 doi: 10.1007/s11709-022-0913-2

摘要: Recently, the application of detrital coral as an alternative to natural aggregates in marine structures has attracted increased attention. In this study, research on the compressive performance of coral aggregate concrete (CAC) confined using steel stirrups with anti-rust treatment was experimentally conducted. A total of 45 specimens were cast, including 9 specimens without stirrups and under different strength grades (C20, C30, and C40) and 36 specimens under different strength grades (C20, C30, and C40). Moreover, three stirrup levels (rectangular, diamond-shaped compound, and spiral stirrups) and different stirrup spacings (40, 50, 60, and 70 mm) were used. Subsequently, the stress−strain curves of specimens subjected to axial loading were measured. The effects of the stirrup spacing and stirrup configurations on the stress and strain were investigated, respectively, and the lateral effective stress of the different stirrups was calculated based on the cohesive-elastic ring model and modified elastic beam theory. Moreover, a damage-constitutive model of CAC considering the lateral stress was set up based on damage mechanics theory. The results indicated an increase in the stress and strain with a decrease in the stirrup spacing, and the adopted stirrup ratio had a better strengthening effect than the different concrete grades, and the variation in the deformation was restricted by the performance of coral coarse aggregate (CA). However, an increment in the lateral strain was observed with an increase in the axial strain. The lateral stress model showed a good agreement with the experimental data, and the proposed damage-constitutive model had a good correlation with the measured stress−strain curves.

关键词: coral aggregate concrete     stress−strain curves     lateral effective stress     peak stress     axial−lateral curves     damage-constitutive model.    

Endochronic damage constitutive model for fully-graded aggregate mass concrete

SONG Yupu, WANG Huailiang

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 274-280 doi: 10.1007/s11709-007-0035-x

摘要: The behavior of deformation and strength of a fully-graded aggregate concrete under complex stress state is the basis of the nonlinear analysis and design for mass concrete structures such as concrete dams. In this paper, based on the combined endochronic theory with damage mechanics and on the quantities of experimental data, an endochronic damage constitutive model suitable for various aggregate grade concrete is proposed. This model takes into consideration the scale effect and the effect of wet screen sieve of aggregate in which the concept of yield surface is not needed and the difference of damage evolution rule of various graded aggregate concrete is a concern. The proposed model is used to analyze the deformation and strength of fully-graded aggregate mass concrete and the wet screened aggregate concrete specimens. The calculated results are in good agreement with experimental data, which can be used as a guide for the design of arch dams and other mass concrete structures.

关键词: concept     surface     design     concern     strength    

Unified description of sand behavior

Feng ZHANG, Bin YE, Guanlin YE

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 121-150 doi: 10.1007/s11709-011-0104-z

摘要: In this paper, the mechanical behavior of sand, was systematically described and modeled with a elastoplastic model proposed by Zhang et al. [ ]. Without losing the generality of the sand, a specific sand called as Toyoura sand, a typical clean sand found in Japan, has been discussed in detail. In the model, the results of conventional triaxial tests of the sand under different loading and drainage conditions were simulated with a fixed set of material parameters. The model only employs eight parameters among which five parameters are the same as those used in Cam-clay model. Once the parameters are determined with the conventional drained triaxial compression tests and undrained triaxial cyclic loading tests, then they are fixed to uniquely describe the overall mechanical behaviors of the Toyoura sand, without changing the values of the eight parameters irrespective of what kind of the loadings or the drainage conditions may be. The capability of the model is discussed in a theoretical way.

关键词: constitutive model     sand     stress-induced anisotropy     density     structure    

钨合金的冲击拉伸行为及其本构和断裂判据的表述

张宝,丁淳彤,刘宝华,陈雪莲

《中国工程科学》 2003年 第5卷 第3期   页码 44-50

摘要:

利用飞轮式Hopkinson拉杆实验技术对钨质量分数为93% 的钨合金在-50~100℃温度范围、应变率ε=102~103s-1区间的动态拉伸性态进行了测试,提供了相应的σ-ε曲线和最大拉伸失效应变,并以此为依据建立了该合金动态拉伸行为的本构关系,提出了该合金受动载发生塑性失稳以致发生拉断的判据。利用断口分形分析理论,对试件拉伸断口微观特征所作的分析和对宏观力学性态实验所作的结论给予了有力的支持。

关键词: 动态拉伸本构模型     钨合金     断裂失效判据    

Confining pressure effect on dynamic response of high rockfill dam

Xuexing CAO, Yunlong HE, Kun XIONG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第1期   页码 116-126 doi: 10.1007/s11709-010-0014-5

摘要: Studies show that the dynamic properties of rockfill are strongly dependent on the confining pressure. Therefore, confining pressure effect has become a very important factor in the seismic analysis of high rockfill dam. The relationships of dynamic shear modulus versus dynamic shear strain and damping ratio versus dynamic shear strain had been improved to a certain degree on the basic of widely used Hardin-Drnevich constitutive model in this paper. Then a new model that could consider confining pressure effect has been established. Regression analysis was carried out of the dynamic triaxial experimental data of the damming materials in the Changheba hydropower station of Sichun Province, China. The results show that, the new model can fit the test data well under various confining pressures. A corresponding computational procedure was compiled and applied in the dynamic response analysis of the Changheba Dam. Comparing the calculation results between the new constitutive model and the ordinary Hardin-Drnevich model, it can be seen that the result is conservative to some extent without considering confining pressure effect.

关键词: confining pressure effect     high rockfill dam     dynamic response     Hardin-Drnevich constitutive model    

富水全、强风化砂岩强度特性试验及本构关系探讨

邹翀,雷胜友,岳喜军,宋妍,高攀

《中国工程科学》 2011年 第13卷 第1期   页码 74-80

摘要:

针对富水全、强风化砂岩的特点,进行了该砂岩的基本物理力学性质、化学成分实验,然后通过单轴、三轴压缩实验研究了爆破扰动、含水量、试样层理对砂岩应力-应变强度特性的影响。发现砂岩遇水软化,粘聚力大幅度降低,表现出显著的各向异性;爆破扰动后,岩石试样的单轴抗压强度减低,弹模减小,泊松比增大;由于砂岩具有明显的节理性,按两种方向加载所得到的岩石试样强度明显不同;根据实验所得应力-应变曲线特点,发现用修正的Duncan-Zhang模型可以很好地描述砂岩的前应力-应变曲线。

关键词: 砂岩     含水量     强度     爆破扰动     节理     本构关系    

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 1025-1037 doi: 10.1007/s11709-021-0741-9

摘要: The understanding of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill (FR-CPB) play crucial roles in the successful implementation of reinforcement technique in underground mine backfilling operations. However, very limited studies have been performed to gain insight into the evolution of compressive and tensile behaviors and associated mechanical properties of FR-CPB under various curing temperatures from early to advanced ages. Thus, this study aims to investigate the time (7, 28, and 90 d)- and temperature (20°C, 35°C, and 45°C)-dependence of constitutive behavior and mechanical properties of FR-CPB. The obtained results show that pre- and post-failure behaviors of FR-CPB demonstrate strongly curing temperature-dependence from early to advanced ages. Moreover, the pseudo-hardening behavior is sensitive to curing temperature, especially at early ages. Furthermore, the mechanical properties including elastic modulus, material stiffness, strengths, brittleness, cohesion, and internal friction angle of FR-CPB show increasing trends with curing temperature as curing time elapses. Additionally, a predictive model is developed to capture the strong correlation between compressive and tensile strength of FR-CPB. The findings of this study will contribute to the successful implementation of FR-CPB technology.

关键词: cemented paste backfill     fiber reinforcement     constitutive behavior     temperature     tailings    

Several basic problems in plastic theory of geomaterials

Yuanxue LIU, Jiawu ZHOU, Zhongyou LI, Chen CHEN, Yingren ZHENG

《结构与土木工程前沿(英文)》 2009年 第3卷 第1期   页码 81-84 doi: 10.1007/s11709-009-0016-3

摘要: Based on the basic mechanical properties of geomaterials, it was proven that the Drucker Postulate and the classical theory of plasticity can not be applied to geomaterials. Moreover, several basic problems of plastic theory of geomaterials were discussed. Based on the strict theoretical analysis, the following have been proven: the single yield surface model based on the classical theory of plasticity is unsuitable for geomaterials whether the rule of associated flow is applied or not; the yield surface of geomaterials is not unique, and its number is the same as the freedoms of plastic strain increment; the yield surface is not convex; and the rule of associated flow is unsuitable for geomaterials.

关键词: constitutive relation     geomaterials     classial plastic theory     Drucker Postulate     yield surface     flow rule    

新型碳酚醛材料动静态力学性能和本构关系研究

张泰,王肖钧,王志海,郭扬,王元博

《中国工程科学》 2006年 第8卷 第5期   页码 63-68

摘要:

研究了碳纤维增强酚醛复合材料在不同温度下的动静态压缩力学性能,碳酚醛材料不但是应变率敏感材料,也是温度相关材料;提出了一个非线性粘弹性本构方程,通过对实验应力-应变曲线的拟合给出了本构方程的材料参数,讨论了温度对本构方程参数的影响;分析了材料力学行为的时温等效性,给出了不同加载条件下的时温等效曲线。

关键词: 碳酚醛     力学性能     粘弹性     本构模型     时温等效    

Multiscale computation on feedforward neural network and recurrent neural network

Bin LI, Xiaoying ZHUANG

《结构与土木工程前沿(英文)》 2020年 第14卷 第6期   页码 1285-1298 doi: 10.1007/s11709-020-0691-7

摘要: Homogenization methods can be used to predict the effective macroscopic properties of materials that are heterogenous at micro- or fine-scale. Among existing methods for homogenization, computational homogenization is widely used in multiscale analyses of structures and materials. Conventional computational homogenization suffers from long computing times, which substantially limits its application in analyzing engineering problems. The neural networks can be used to construct fully decoupled approaches in nonlinear multiscale methods by mapping macroscopic loading and microscopic response. Computational homogenization methods for nonlinear material and implementation of offline multiscale computation are studied to generate data set. This article intends to model the multiscale constitution using feedforward neural network (FNN) and recurrent neural network (RNN), and appropriate set of loading paths are selected to effectively predict the materials behavior along unknown paths. Applications to two-dimensional multiscale analysis are tested and discussed in detail.

关键词: multiscale method     constitutive model     feedforward neural network     recurrent neural network    

Cyclic behavior of prefabricated reinforced concrete frame with infill slit shear walls

Kui XIAO,Qilin ZHANG,Bin JIA

《结构与土木工程前沿(英文)》 2016年 第10卷 第1期   页码 63-71 doi: 10.1007/s11709-015-0294-x

摘要: A composite structural system consisting of prefabricated reinforced concrete frame with infill slit shear walls (PRCFW), with good ductility, is a new type of earthquake resistant structure. Pseudo-static tests were performed to evaluate the seismic behavior of the PRCFW system. Two one-bay, two-story PRCFW specimens were both built at one-half scale. Additional computational research is also conducted to enhance the nonlinear analytical capabilities for this system. Combined with the concrete damaged plastic (CDP) model provided by finite element program ABAQUS and the constitutive model of concrete proposed by Chinese code, the damage process of the PRCFW structure under cyclic load is simulated. The simulated results show a good agreement with the test data, the dynamic behavior of the PRCFW system can be simulated sufficiently accurate and efficient to provide useful design information. The experimental and numerical study show that this system has the potential to offer good ductility and energy absorption capacity to dissipate input energy, and stiffness adequate for controlling drift for buildings located in earthquake-prone regions.

关键词: slit shear wall     constitutive model     cyclic     seismic     damage    

标题 作者 时间 类型 操作

Numerical modeling of nonlinear deformation of polymer composites based on hyperelastic constitutive

Qingsheng YANG, Fang XU

期刊论文

Hypoplastic constitutive modeling of wetting deformation of weathered rockfill materials

Erich BAUER, Zhongzhi FU, Sihong LIU,

期刊论文

Development of a constitutive model for rockfills and similar granular materials based on the disturbed

Mehdi VEISKARAMI, Ali GHORBANI, Mohammadreza ALAVIPOUR

期刊论文

Precision glass molding: Toward an optimal fabrication of optical lenses

Liangchi ZHANG,Weidong LIU

期刊论文

Damage-constitutive model for seawater coral concrete using different stirrup confinements subjected

期刊论文

Endochronic damage constitutive model for fully-graded aggregate mass concrete

SONG Yupu, WANG Huailiang

期刊论文

Unified description of sand behavior

Feng ZHANG, Bin YE, Guanlin YE

期刊论文

钨合金的冲击拉伸行为及其本构和断裂判据的表述

张宝,丁淳彤,刘宝华,陈雪莲

期刊论文

Confining pressure effect on dynamic response of high rockfill dam

Xuexing CAO, Yunlong HE, Kun XIONG,

期刊论文

富水全、强风化砂岩强度特性试验及本构关系探讨

邹翀,雷胜友,岳喜军,宋妍,高攀

期刊论文

Time- and temperature-dependence of compressive and tensile behaviors of polypropylene fiber-reinforced cemented paste backfill

期刊论文

Several basic problems in plastic theory of geomaterials

Yuanxue LIU, Jiawu ZHOU, Zhongyou LI, Chen CHEN, Yingren ZHENG

期刊论文

新型碳酚醛材料动静态力学性能和本构关系研究

张泰,王肖钧,王志海,郭扬,王元博

期刊论文

Multiscale computation on feedforward neural network and recurrent neural network

Bin LI, Xiaoying ZHUANG

期刊论文

Cyclic behavior of prefabricated reinforced concrete frame with infill slit shear walls

Kui XIAO,Qilin ZHANG,Bin JIA

期刊论文