共查询到19条相似文献,搜索用时 78 毫秒
1.
2.
为研究碳纤维约束高强混凝土单轴受压性能和应力-应变关系,进行了碳纤维约束高强混凝土棱柱体单轴受压试验,考察了混凝土强度、碳纤维包裹层数等参数对其单轴受压性能的影响规律;将试验结果与国内外七个碳纤维约束混凝土方柱的应力-应变模型进行了比较,发现已有模型不能准确反映碳纤维约束高强混凝土的单轴受压性能。 相似文献
3.
基于不可逆热力学原理提出一种简单的混凝土类准脆性材料的损伤本构模型,具有参数相对少、公式表达简单、易于数值实现等特点。采用双标量损伤变量来描述混凝土的拉伸和压缩不等性、刚度及强度退化特性;通过分解自由能为体积和剪切两部分,在体积部分引入单边效应函数来考虑裂纹闭合效应;通过对损伤变量的黏性化处理以及附加弹性条件来考虑率相关性。给出混凝土试件在单轴拉伸和压缩、双轴加载、三轴压缩以及应变率影响的不同加载条件下的数值计算结果,与试验结果比较吻合。通过对缺口梁三点弯曲加载破坏过程和重力坝地震响应的数值模拟,验证损伤模型在大尺度混凝土结构的非线性分析方面,具有较好的收敛性和计算能力。 相似文献
4.
针对模型试验用微粒混凝土未充分考虑质量密度相似条件的问题,提出了在基础配合比(大理石粉∶水泥∶重晶石砂∶水=1∶1∶16∶1.6)的基础上,用铁砂和铅丸等质量替代骨料(10%、20%、30%)的加重微粒混凝土配合比设计试验方案,研究其力学性能以及应力-应变本构关系。结果表明:各替代组表观密度均在3 000 kg/m3以上,表观密度提升效果明显。两替代组的28 d抗压强度均低于11 MPa,弹性模量在1.11×104~1.72×104MPa之间,符合低抗压强度、低弹性模量的相似要求。两替代组的破坏形态以及应力应变全曲线形状与普通混凝土相似,并对比分析两替代组的峰值应力与峰值应变随替代组的变化规律。建立了适用加重微粒混凝土的分段式本构方程以及损伤本构方程,两种方程的预测结果与试验数据具有较好的一致性。试验结果满足模型试验的相似要求,并通过本构关系的研究有利于了解原型混凝土的力学性能与破坏机理,为相关试验人员提供参考和借鉴。 相似文献
5.
6.
7.
混凝土二维本构关系试验研究 总被引:1,自引:0,他引:1
本文采用Instron-8506四立柱液压伺服试验机对混凝土二维本构关系进行了系统的试验研究。在应变控制加载的条件下测得了混凝土板式试件在二轴压-压区和拉-压区的双轴应力应变全曲线。分析了试件的破坏特点,讨论了不同应变组合条件下试件的破坏模式。提取全曲线的特征参数,建立了应力空间和应变空间的强度包络线,并与经典试验结果进行了对比。研究表明双轴应变比例控制加载条件下可以测得混凝土板式试件的二轴应力应变全曲线,所得曲线具有一定的精度和可信性。本文得到的应力应变全曲线和包络线为多轴本构关系的研究以及复杂结构设计提供了依据。 相似文献
8.
现有混凝土本构关系主要是基于成熟的经典弹塑性模型所建立的,弹塑性模型在数学上较严格,但是与混凝土材料破坏机理不协调,各国学者针对混凝土这类特殊多相复合材料提出了很多基于不可逆热力学理论的损伤本构模型。系统综述了混凝土损伤本构研究的成果,在分析了各个有代表意义的混凝土损伤本构模型基础之上,对比研究了各个模型的特点及各自适用范围,通过总结前人成果,为损伤本构模型研究提供了思路。 相似文献
9.
为研究型钢高强混凝土界面黏结性能,对9个型钢高强混凝土试件进行推出试验,分别考虑混凝土强度、配箍率、保护层厚度和型钢锚固长度对型钢高强混凝土界面黏结性能的影响。观察试件的加载过程和裂缝发展形态,分析了试件破坏形态,得到试件加载端荷载-滑移曲线。通过分析沿型钢锚固方向应变和界面黏结应力的分布规律,运用灰色关联理论建立了黏结应力计算式,并推导出荷载-滑移曲线关系表达式。讨论了影响界面滑移损伤变量的关系。结果表明:各试件加载端荷载-滑移曲线走势基本相同;灰色关联理论能够较好地反映黏结应力与各影响因素之间的关系,其中保护层厚度与黏结应力相关性最好;推导的黏结应力算式的计算精度能达到98%;提出的黏结应力-滑移的本构关系数学表达式拟合度较好;界面损伤发展程度与各影响因素关系紧密。 相似文献
10.
11.
进行了系统的粗粒土与结构接触面静动力学试验以研究其本构规律。基于试验得到的宏观和细观测量结果,归纳总结了粗粒土与结构接触面静动力学特性的五条基本规律,即:(1)抗剪强度与法向应力近似成线性关系;(2)在一条法向应力不变条件下的单调剪切应力路径中,剪应力随着剪应变的增加而不断增长并趋向于一稳定值;(3)剪胀体应变由不可逆性和可逆性的体应变分量构成,可逆性剪胀体应变表现出明显的接触面异向性,与剪胀体应变有关的剪应变在总剪应变中所占比例在不同剪切阶段是不同的;(4)压缩性随着法向应力的增大而逐渐降低;(5)受载过程中发生物理状态及力学特性的演化并逐渐趋于稳定。 相似文献
12.
13.
《Structure and Infrastructure Engineering》2013,9(5):353-367
This study aims to import multi-source information fusion (MSIF) into structural damage diagnosis to improve its validity. Two structural damage identification methods based on MSIF are put forward, one of which is to fuse two or more structural damage detection methods by MSIF and another of which is the improved modal strain energy method by multi-mode information processing based on MSIF. Through a concrete plate experiment it is proved that, if two methods are integrated by character-level information fusion, structural initial damages can be more accurately identified than by a single method. In a simulation of a concrete box beam bridge, it is indicated that the improved modal strain energy method has a nice sensitivity to structural initial damages and a favorable robusticity to noise. These two structural damage diagnosis methods based on MSIF have good effects on structural damage identification and good practicability to actual structures. 相似文献
14.
15.
结合具体工程,介绍了型钢混凝土梁设计以及型钢混凝土梁与混凝土柱连接节点设计情况,对整体进行了计算分析,得出了悬挑结构变形能力得到改善,承载力满足要求的结论,并总结了工程组合结构设计的构造要求及确保工程质量的技术措施。 相似文献
16.
《岩石力学与岩土工程学报(英文版)》2022,14(6):1710-1721
Underground rock dynamic disasters are becoming more severe due to the increasing depth of human operations underground. Underground temperature and pressure conditions contribute significantly to these disasters. Therefore, it is important to understand the coupled thermo-mechanical (TM) behaviour of rocks for the long-term safety and maintenance of underground tunnelling and mining. Moreover, investigation of the damage, strength and failure characteristics of rocks under triaxial stress conditions is important to avoid underground rock disasters. In this study, based on Weibull distribution and Lemaitre’s strain equivalent principle, a statistical coupled TM constitutive model for sandstone was established under high temperature and pressure conditions. The triaxial test results of sandstone under different temperature and pressure conditions were used to validate the model. The proposed model was in good agreement with the experimental results up to 600 °C. The total TM damage was decreased with increasing temperature, while it was increased with increasing confining pressure. The model’s parameters can be calculated using conventional laboratory test results. 相似文献
17.
In this paper, a constitutive law describing the wood behaviour, as elasto-plastic orthotropic material with 3D finite element model, is presented. Anisotropic elasto-plastic constitutive law with hardening associated with material densification, without distinction between radial and tangential properties, was used for the compressive behaviour. The main novelty of the developed 3D F.E. model, among the models accounting for hardening is the coupling between the anisotropic plasticity and the ductile densification. The model was successfully implemented in the commercial ABAQUS software and validated in the context of uniaxial compressive loading and on one-bolt wood connection tests. The results for the uniaxial compressive loading were compared with the published experimental ones, showing good agreements and demonstrate clearly the effect of the densification on the plastic behaviour. Further, the results obtained on one-dowel wood connection were compared with experiments showing the capability of the model to simulate accurately the non-linear behaviour of bolted joints until failure. 相似文献
18.