查询词典 season crack

The main research tasks and results are as follows:(1) Through comparing the stress intensity factor of compact tension specimen calculated by finite element software with the theoretical value, the feasibility of calculating fracture parameters of crack tip in ABAQUS software was verified.(2) The relationship between the elastic modulus of the material and research scale was studied based on deriving the cohesive stress theory and other relevant theories. And the elastic modulus of the material on meso-scale was determined.(3) Global model and sub-model of the finite element were built in th...e macro-scale, and stress-strain field nearby the crack tip was analyzed, and the results show that the detailed stress-strain in the crack tip could be obtained by using the sub-model technique.(4) In meso-scale, the crack growth model was also established by assuming the crack propagating along the grain boundary, and the detailed stress-strain field in the crack tip was obtained.(5) The effect of crack length on Von Mises stress, and maximum principal stress and strain was analyzed in meso-scale when equivalent KI equals 30MPa.m1/2. And the results show that except for crack tip area, the stress-strain distribution in whole specimen is not affected.

主要完成研究内容和取得成果如下：(1)利用有限元软件计算出紧凑拉伸试样的裂纹尖端应力强度因子KI值，其结果与理论值一致，从而验证了利用ABAQUS计算裂纹尖端相关断裂参量的可行性；(2)在研究内聚应力等相关理论的基础上，推导出了研究尺度与材料弹性模量的近似关系，并确定了介观尺度上的弹性模量；(3)在宏观尺度上建立了全局有限元计算模型和子模型，得到了裂纹尖端应力应变场分布，结果表明利用子模型技术获得比较准确的裂纹尖端应力应变场分布是可行的；(4)在介观尺度上利用平均晶粒尺度的方式建立了裂纹沿晶扩展模型，得到了裂纹尖端断裂过程区的微观应力应变场；(5)当应力强度因子为30MPa.m1/2时，分析了介观尺度上在裂纹沿晶扩展过程中裂纹长度对Mises应力、最大主应力和应变的影响，结果表明，裂纹扩展长度对试样整体应力应变分布影响不大，而对裂纹尖端区域有较大影响；(6)介。。。

Crack propagation problems under the influence of the edges of the crack subjected to homogenous loads, the origin of the coordinates subjected to concentrated increasing loads, the central zone of the edges of the crack subjected to homogenous loads, the certain point of the edges of the crack subjected to moving unit step loads, the origin of the coordinates subjected to moving increasing loads Px m, the edges of the crack subjected to instantaneous impulse loads, the edges of the crack subjected to moving concentrated variable loads, the origin of the coordinates subjected to point loads, the edges of the crack subjected to a constant moving concentrated loads and the origin of the coordinates subjected to instantaneously moving impulse loads are studied respectively, and the analytical solutions of dislocation distribution function have been obtained.

同时对裂纹面受均布载荷、坐标原点受集中增加载荷、裂纹面中心区受均布载荷、裂纹面上某点受运动阶跃载荷、坐标原点受运动增加载荷Px m、坐标原点受瞬时冲击载荷、裂纹面受运动集中变载荷、坐标原点受集中载荷、裂纹面受常数运动集中载荷、坐标原点受瞬时运动冲击载荷作用下的裂纹扩展问题分别进行了研究，获得了位错分布函数的解析解。

The crack that see much of most in several residence is that a layer maneuver a wall to hand over to connect place to have the stairs form the crack creation;Hand over to connect place or beam bottom and wall body to have the level crack the creation in the house noodles and the wall body;There is Shu under the first floor window sill toward the crack creation, the window sill of each floor two wall window way outside the layer four Cape existence inclined crack;Small scaled and hollow carve in the reinforced concrete pillar and the Mao a piece of fill a wall of mutually knot existence the Shu is to the crack;It is carve a piece periphery a creation crack.

随着国家保护耕地措施的实施，粘土砖的使用逐步得到控制，砼小型空心砌块在住宅工程中开始得到越来越多的应用期刊文章分类查询，尽在期刊图书馆在多层住宅中最常看到的裂缝是顶层纵横墙交接处有阶梯形裂缝产生；在屋面与墙体交接处或梁底与墙体间有水平裂缝产生；在底层窗台下有竖向裂缝产生，各个楼层的窗台两角和顶层外墙窗口四角处有斜裂缝存在；在钢筋混凝土柱和砼小型空心砌块填充墙的相结处有竖向裂缝存在；在砌块周边产生裂缝。

The crack that see much of most in several residence is that a layer maneuver a wall to hand over to connect place to have the stairs form the crack creation;Hand over to connect place or beam bottom and wall body to have the level crack the creation in the house noodles and the wall body;There is Shu under the first floor window sill toward the crack creation, the window sill of each floor two wall window way outside the layer four Cape existence inclined crack;Small scaled and hollow carve in the reinforced concrete pillar and the Mao a piece of fill a wall of mutually knot existence the Shu is to the crack;It is carve a piece periphery a creation crack.

随着国家保护耕地措施的实施，粘土砖的使用逐步得到控制，砼小型空心砌块在住宅工程中开始得到越来越多的应用在多层住宅中最常看到的裂缝是顶层纵横墙交接处有阶梯形裂缝产生；在屋面与墙体交接处或梁底与墙体间有水平裂缝产生；在底层窗台下有竖向裂缝产生，各个楼层的窗台两角和顶层外墙窗口四角处有斜裂缝存在；在钢筋混凝土柱和砼小型空心砌块填充墙的相结处有竖向裂缝存在；在砌块周边产生裂缝。

It is clarified for the first time that the thermal fatigue failure of solder joint is actually a creep strain low cycle fatigue failure, and a physical model for creep fatigue crack propagation has been proposed. It was pointed out that creep strain increases in the high stress area ahead of the tip of thermal fatigue crack, results on one hand that the slide of crack tip increase, inactivation more serious and crack close length increases, the other hand, that intergranular crack exists, whose direction will affect the fatigue crack propagating.

本文首次阐明了焊点的热循环失效本质上是以焊点内循环蠕变为主要应变的低周疲劳失效，并在此基础上提出了蠕变疲劳裂纹扩展的物理模型，指出热循环裂纹前端的高应力区内，蠕变加剧，使裂纹前端滑移增加，裂纹钝化加剧，导致随后的裂纹闭合扩展长度增加；同时蠕变也使裂纹前端的高应力区出现晶间裂纹，蠕变沿晶裂纹对主裂纹扩展的影响取决于沿晶裂纹的连接方向。

In this paper, the factors that may cause crack breaking of concrete pavement of several built highways were analyzed systematically and thoroughly. From analysis to site experiments and calculation, it is believed that crack breaking is mainly caused by factors as follows: 1 、 Unqualified sedimentation and losing stabilization of the roadbedinduced crack in the early; 2、 Construction technology、 materials and incorrect treatment methodswere adopted;3 、 Crack breaking induced by thermal stress; 4、 Water cant circulate makes crack cause;With regard to the afore-mentioned problems, corresponding preventive measures, qualified control indices and site control approach are presented based on analysis theory and site experiments.

本文在全面系统地分析已建成的高速公路水泥混凝土路面产生的原因的基础上，通过现场试验及计算分析，确定了高速公路水泥混凝土路面裂缝的主要影响因素有以下几个方面： 1、路基的不均匀沉降、失稳是早期裂缝产生的主要因素； 2、施工工艺、材料问题及养护方法不当； 3、温度应力产生的裂缝； 4、排水不畅影响裂缝产生；针对上述问题，通过理论分析及现场数据提出相应的质量控制目标、现场控制方法。

The application of reflected optical difference system in surface crack of aluminum detection is also discussed. By analyzing the experimental data, we found that the reflected pulsed wave techniques could be used to measure the position of crack precisely and depth imprecisely. Transmitted wave contain much size information of the crack, despite without position information. The spectrum of transmitted is sensitive to the depth of crack. The deeper the crack is, the narrower the spectrum bandwidth is.

使用自建的光偏转差分检测系统，对铝样品中多种表面缺陷进行了检测，对表面波直达波，反射波，透射波波形及频谱进行了分析，讨论超声表面波与各种缺陷相互作用后的变化，通过对实验结果的分析，发现缺陷脉冲发射法可以精确测定缺陷位置，粗略估计缺陷深度；而透射法测的波形无法定出缺陷位置，但包含了缺陷大小信息，透射波频谱对缺陷深度非常敏感，随缺陷深度的加深，频谱不断的左移。

According to the stress-strain complete process curve, the total volumetric strains and crack induced 1 volumetric strains is adopted as damage parameters for analyzing the five phases during the crack growth (crack closure , linear elastic, stable crack growth, unstable crack growth and post failure).

通过压缩试验获得的脆性岩石的全应力应变曲线，利用体积变量和裂纹体积变量等损伤变量分析得出裂纹发展的五个阶段即：压密、弹性、微裂纹稳定扩展、裂纹非稳定扩展和峰后失稳等。

Secondly, the paper carries on the destruction processes and the stress distribution situation numerical simulation of the concrete three point bending specimen with bias crack under static load function,, and analyze specimen crack expansion and the destruction mechanism, obtain the reason that the crack expanding flectional way is because the material nonuniformity, in the same time, from the specimen destruction process chart we can see that the crack bias degree has some influence on the crack expansion way.

其次论文对含偏置裂纹的混凝土三点弯曲试件在静态载荷作用下的破坏过程和应力分布情况进行了数值模拟，并对试件的裂纹扩展和破坏机理进行了分析，得出裂纹扩展的曲折性是由于材料不均匀性所引起的，同时从试件的破坏过程图中可以看出，裂纹的偏置程度对裂纹的扩展路径有一定的影响。

To give the definition of the mass concrete and to concrete\'s cracks together with practical meanings of control ,and give a brief review on the research in the field at home and abroad, at last, methods to control temperature crack of the mass concrete from several aspects such as design measures,concrets material, construction schedules.etc are summed up; To explain the physical mechanics of the concrete and computing methods-Difference Method and Finite Element Method, and illustrate the application of their specific methods repectively;Several temperature factors that can influence the temperature stress of mass concrete baseplate are analyzed. The influence degree of temperature factor can be got through the ANSYS simulation computation the control of temperature can control the temperature stress, consequently control the temperature crack of mass concert baseplate; through the influence of the crack resistance ability of mass concrete baseplate which takes the reinforcement as a part is analyzed. By ANSYS simulation, the best suited volume ratio of reinforcement is found out, at same time the layout of reinforcement with the same volume ratio can also affect the resistance ability of mass concrete baseplate. Sum up of above analysis, anti-crack function of steel bar in early mass concrete baseplate is obvious, so it\'s necessary to consider beneficial effect of construction steel bar in research of temperature control on mass concrete baseplate.

本文先容了大体积混凝土及混凝土裂缝的基本概念，对国内外在这个领域里的研究现状作了扼要叙述，并从结构设计、混凝土材质、施工措施等方面总结了大体积混凝土温度裂缝控制的方法及防止措施；阐述了混凝土的基本物理力学性能，总结了大体积混凝土温度计算的方法——差分法和有限元法，并分别举例说明其具体应用的方法；分析了影响大体积混凝土底板温度应力的几种温度因素，利用ANSYS模拟计算，得出了每种因素的影响程度，通过分析提出了在这几种温度影响因素下如何通过控制温度以达到控制温度应力从而来控制裂缝的具体建议；针对大体积混凝土基础底板中配筋的不同对混凝土底板抗裂能力的影响不同，利用ANSYS进行模拟分析，得出底板中最合适的体积配筋率，同时分析了在相同体积配筋率下钢筋的具体布置对大体积混凝土基础底板抗裂能力的影响，分析表明，配置钢筋对混凝土结构的开裂阻止作用明显，在研究大体积混凝土温度裂缝题目时，要考虑钢筋在其中的有利作用。

More direct, directer ; most direct, directest

径直的，笔直的

Do you know how to use a chain saw?

你知道如何使用链锯吗？