破坏应力

Based on the laminate theory, a laminate weakened by damage is treated as an anisotropic thin plate. Using the complex potential method in the plane theory of elasticity of an anisotropic body, the series solution of finite anisotropic thin plate containing an elliptical inclusion is proposed with the help of Faber series. A hybrid element with an elliptical inclusion for anisotropic materials is obtained by using the hybrid variable principle, and the element efficiency is verified by numerical examples. The state of the damage is modeled by an elliptical soft inclusion, and using the point stress criterion based on characteristic curve and Yamada-Sun etc. criteria, the prediction of the strength of a composite laminate with damage is set up. The effects of various parameters on the stress distribution and the residual strength of a composite laminate weakened by damage are detailedly studied.

首先基于经典层板理论，将复合材料层板的弹性问题化归为均匀各向异性板来求解；采用各向异性体平面弹性理论中的复势方法，以Faber级数为工具，给出了有限大含椭圆核各向异性板弹性问题的级数解形式；利用杂交变分原理，成功导出含椭圆核各向异性板杂交应力有限元，并用算例验证了该单元的可行性和有效性；采用含刚度折减椭圆形弹性核的冲击损伤模型，引入基于特征曲线和Yamada-Sun破坏准则的点应力判据，建立了含损伤复合材料层板剩余强度的分析方法；通过数值计算详细讨论了各种几何参数对损伤层板应力分布、剩余强度的影响，得到了一系列对工程应用具有实用价值的结论。

Took Chongqing Gong-he tunnel as an engineering example and studied the failure mechanism of surrounding rock and the correlation with bolt support system by using the methods of theoretical analysis, modeling test, numerical simulation and in situ test, some helpful conclusions were arrived as follows.Firstly, a new failure criterion for transversely isotropic rock mass was proposed with consideration of bedding plane orientation and major principal stress, and the corresponding algorithm, arrived through VC++6.0, can be easily embedded into the software FLAC3D for the geotechnical calculation.

论文在国家自然科学基金专项基金创新群体基金项目(No.50621403)以及国家自然科学基金重点项目"隧道与地下空间工程结构物的稳定性与可靠性(No.50334060)"的资助下，以共和隧道为示范工程，运用理论分析、物理模型实验、数值模拟和现场测试等手段，对共和隧道大埋深段层状岩体的围岩变形破坏机理、锚杆支护力学效应及围岩-支护结构的变形特征等内容进行了研究，其主要研究成果有：①在总结和探讨国内外学者提出的层状岩体经验型连续介质破坏准则基础上，结合层状岩体力学特性，考虑层面方向和最大主应力方向两个影响因素，提出了共和隧道层状岩体横观各向同性破坏准则；采用汇编语言VC++6.0实现了横观各向同性弹塑性本构关系的算法，并嵌入FLAC3D有限差分数值分析软件接口中实现数值运算。

How to easily and reasonably determine the value of principal stress in the direction of plane strain is the key point.

基于弹塑性理论及土的试验规律，在平面应变的简单加载条件下，假定主应力之间的关系为双线性函数，并利用一维固结和破坏时的主应力状态，确定双线性函数的系数，得到平面应变方向上主应力计算公式的一个较合理形式，为应力状态和材料性质的函数。

We also elaborated upon the relations between immediately adjacent fibers and loadings、interfacial bonding、residual stress、matrix parameters and material elastic properties of two kinds of fibers and the influence on the observed"hybrid effect"in a hybrid composite.

计算了混杂复合材料由于高模量纤维破坏引起的高低模量纤维应力集中系数，详细分析了载荷大小、界面结合强度、残余应力和参与混杂的两种不同纤维及基体的弹性性质等与邻近纤维应力集中的关系及其对复合材料"混杂效应"的影响。

First of all, the paper carried out test study on four two-spanned model members of FSMRCWB, including three 1/2-scaled two-storeyed models and one 1/3-scaled three-storeyed model. The paper analyzed the test results, including analysis on mechanical property of the composite wall beam under vertical loads, and failure mode, deformation capacity, aseismic performance under horizontal loads and constant vertical loads. Secondly, the nonlinear property of concrete is studed and the nonlinear models of FSMRCSS is builded by ANSYS. Last, The paper studies the result of ANSYS, which mainly includes the loading-displace curve of FSMRCSS under horizontal loads and constant vertical loads, the mechanics of arch under vertical loads lonely and under horizontal loads and constant vertical loads respectively, and status of the distribution and changing of vertical stress and cross shear on the surface of the suporting beam, and the influence of span ratio and hole.All in all, the caculating results are in good agreement with the test results.

本文首先进行了三个1/2比例的两跨两层和一个1/3比例的两跨三层的框支密肋复合墙梁的模型试验，分析了框支密肋复合墙梁在竖向荷载作用下的受力性能，以及在竖向荷载与水平低周反复荷载共同作用下的受力性能、变形性能、滞回性能、耗能系数及破坏形态；其次，研究了混凝土的非线性特性，建立了框支密肋复合墙梁非线性有限元模型，并借助大型通用有限元软件ANSYS进行计算；再则，进行了非线性有限元结果分析，主要研究框支密肋复合墙梁在竖向荷载与水平地震力共同作用下的荷载位移曲线，分析在竖向荷载单独作用下和在竖向荷载与水平地震力共同作用下墙梁的拱作用，托梁顶面的竖向应力和横向剪应力分布及变化情况，并讨论跨度比、洞口对墙梁拱作用和托梁顶面的竖向应力的影响。

This damage criterion reflects the character of RCC, and shows that stress degree of RCC damage decreasing with heat current density vector and temperature gradient augmenting. If this process of RCC damage is in constant temperature, the damage completely depends on stress degree, which accords with the result of experiment.

结果 碾压混凝土热耗散和损伤耗散累积到一定程度时，损伤破坏就会发生，且随着热流密度矢量和温度梯度增大，碾压混凝土发生损伤破坏的应力水平将降低，如碾压混凝土是一个等温变化过程，则损伤完全取决于应力水平。

Combining the actual rockburst status after excavation, based on the previous research data in the earlier stage, the character of the tectonic stress in Cangling Tunnel is studied. Finite element method is adopted to simulate the site excavation steps. At the same time, the tectonic stress is changed on the boundary of the model to simulate the actual rockburst areas; and the most proximal area's value is adopted to decide the section tectonic stress. Then, other sections' values are revised.

从苍岭隧道的构造应力场特征入手，结合现场开挖后岩爆实际发生状况，在前期研究资料的基础上，利用有限元计算分析，模拟现场实际施工步骤的同时不断改变模型边界上的构造应力来拟合实际岩爆区，以最接近实际破坏范围的计算结果界定区段构造应力值，据此对隧道各区段的构造应力进行修正。

This analytical approach shows that, as increasing the wear flat of indenter, the maximum indentation force needed to develop critical plastic zone increases and its corresponding critical penetration depth also increases slightly, Note that the effect of wear flat will affect rock fracture behavior. In addition, regarding the simulation of the effect of doubled-indenters, result shows that two adjacent indenters may interact each other as reaching the transient/critical relative space between indenters of 2~3. It dicpicts that a proper spacing arrangement between indenters may enhance a efficient mechanical cutting due to the less required maximum indentation force and energy dissipation.

由数值模拟之结果得知，当楔尖磨耗增加时，岩材产生脆性破坏之初裂贯切力随之增加，而其对应之临界贯入深度则亦微幅增加，故磨耗效应确会干扰岩材脆性破坏机制之形成；而由双刀效应之模拟，可知两贯切刀楔互制影响之破坏裂缝生、衍行为，当双刀相对刀距为时，岩材之破坏特徵有明显变化，即定义此为临界相对刀距，并探讨其产生脆性破坏所需初裂贯切力之变动范围及应力重叠区，由此得知适当之刀距安排将有助於减少能量之耗损。

In-situ monitoring gave the following results: 1 a tension stress zone occurred at the bottom of reinforced rock mass which indicated that the role of rock bolting was remarkable; 2 stress concentration at surrounding rock of main shaft was gradually transferred from shaft wall to complete rock mass far from shaft center; 3 vertical displacement was gradually smaller from up to bottom and from center to outside of the reinforced loose rock mass.

首先，建立了主溜井三维有限元计算模型，模拟了主溜井围岩的塌落破坏过程和加固后的加固体的稳定性及变形特性；同时，还采用多点位移计等对加固体的稳定性进行了实地监测。计算结果表明：网棚锚注加固体的纵剖面上的压力和位移规律是①加固体下部局部出现拉应力区，表明锚杆的使用是合理的；②加固体内的应力由塌落中心向周围围岩过渡，应力越来越大，最终将荷载传至围岩中；③从下到上下沉逐渐减小；④从加固体中心到周围下沉位移逐渐减小，且近似一条抛物线。

The methods of stress and strain analysis, failure analysis and safety evaluation for high arch dam in available specification and studies are reviewed in this paper. The main deficiencies for these methods are: the failure modes are not taken into account in failure analysis and safety evaluation, the regimes of failures are not clearly defined, the related methods and criterion are not so reasonable.

在总结高拱坝应力变形分析、破坏分析和安全度评估的现行规范及现有研究方法的基础上，指出这些方法存在的主要问题是：在进行破坏分析和安全度评估时没有考虑拱坝的破坏模式，破坏分析的层次不够明确，分析方法的建立和破坏判据的确定缺乏理论依据。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。