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1.
《浙江大学学报(A卷英文版)》2016,(12)
目的:通过调整非常精细的颗粒,四方晶氧化锆多晶(TZP)在室温下保持稳态四方相,并且具有优异的塑性。然而,当材料变形时,我们必须对超塑性陶瓷在机械应力分布和断裂机制方面有更多的理解。创新点:1.通过材料弹塑性模型;2.使用胡克定律、塑性应变硬化及von Mises降伏准则;3.结合等向性硬化规则及相关联的流动规则。方法:1.开发一个高温超塑性材料在不同应变率拉伸条件下具备不同应力-应变关系的组成律模型及有限元分析模型;2.通过有限元法仿真模拟与实验结果比对;3.验证所提方法的可行性和精确性。结论:1.有限元仿真模拟的应力-应变关系与实验数据吻合较好,对于所研究的四种组合物,最大应力和应变的误差均小于1%。2.有限元仿真模拟的最终变形形状(宽度和厚度)与拉伸试验的结果一致;这些验证证实了所提有限元分析模型的可靠性。 相似文献
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采用波分和空分混合复用技术和LabVIEW,设计了一种可通过单片机控制的光纤Bragg光栅(FBG)传感监测解调系统,实现了温度和应变的实时监测。实验研究表明,在20～100℃范围内,温度监测平均误差0.3℃,标准差0.163℃,实验灵敏度与标定灵敏度之间的灵敏度误差为0.29%;在0～390με应变范围内,应变监测平均误差2.79με,标准差2.63με,悬臂梁上下FBG实验灵敏度与标定灵敏度之间的灵敏度误差分别为0.10%、0.19%。该解调系统实现了高灵活性、高精度的温度和应变监测。 相似文献
3.
碳化硅颗粒增强铝基复合材料(SiCp/Al)有着优异的力学性能,主要表现在强度、刚度、疲劳等方面,在航空航天、光学精密仪器等领域被广泛使用。为研究SiCp/Al材料在缺口方面的力学性能,进行了单轴拉伸试验,使用三维数字散斑应变测量分析系统,测量了SiCp/Al材料的强度和弹性模量等力学性能,并采集了材料颈缩处的位移场和应变场。对实验数据进行分析处理后,获取了Johnson-Cook本构模型所需参数的数据,使用ABAQUS有限元软件模拟SiCp/Al材料拉伸试验。将三维数字散斑应变系统测量的结果与仿真结果进行全场对比分析,结果吻合良好,误差在允许范围内,验证了模拟的合理性和有效性。 相似文献
4.
光纤FP干涉仪是一种新型的温度、应变测试装置。研究了各种FP干涉仪,并利用多光束干涉原理推导了统一的公式。对其进行了模拟仿真,得出了对实验有指导意义的结果。 相似文献
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基于有限差分FLAC5.0的数值模拟,建立工程地质模型,模拟了边坡开挖过程的应力、应变与位移,最终计算得出边坡的安全系数。通过与极限平衡结果相比较,证明了数值模拟的可行性与可靠性。 相似文献
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为了研究路基粒料的吸力依赖性及其对路面响应的影响,在Abaqus中进行了水力学耦合模拟.通过开发用户自定义材料子程序(UMAT),将一个吸力依赖的回弹模量模型整合到商用有限元软件Abaqus中.使用不同吸力条件下的三轴实验结果验证了开发的模型,模拟与试验结果具有良好的一致性.建立了一个三维有限元路面模型,并用开发的本构模型表征路基粒料的吸力依赖性.计算了处于3种不同湿度状态和FWD荷载作用下的路面水力学响应.模拟结果表明:路基粒料的回弹模量对吸力及应力状态具有敏感性;由于吸力下降,高地下水位降低了路基结构整体回弹模量,导致路表最大弯沉、面层层底拉应变、路基顶面压应变增大,相应造成路面使用性能恶化. 相似文献
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由于裂纹尖端的奇异性,应用解析法求解复杂裂纹周边的位移场和应变应力场几乎不可行,然而可以采用数值法,借助ANSYS软件,对裂纹前缘、边缘的位移场和应变应力场进行模拟,模拟结果与断裂力学理论分析几乎一致. 相似文献
9.
基于Gleeble-3500热模拟试验机平台,对6061铝合金进行等温热压缩实验,研究了该合金在变形温度为350~500℃和应变速率为0.01~10s-1条件下的高温流变行为并建立了6061铝合金的Arrhenius本构方程,应用于Deform软件进行热压缩实验模拟基于动态材料模型和Murty准则,建立了6061铝合金在不同应变下的加工图,结合显微组织进行验证。结果表明,该合金材料的流变应力随应变速率增加而增大,随变形温度降低而增大建立的本构方程能较好描述该合金的高温流变行为变形温度为460~500℃,应变速率为0.1~0.5s-1的区域是该合金最佳工艺参数范围。 相似文献
10.
16Mn热轧钢板延性断裂韧度JIC的相关性研究 总被引：1，自引：0，他引：1
探讨了热处理和应变循环加栽对16Mn延性断裂韧度JIC的影响.实验结果表明:16Mn热轧钢板正火后延性断裂韧度JIC约是正火前的3倍,应变循环加栽对钢材的延性断裂韧度JIC的影响很明显,钢材单调拉伸0.3%应变后,延性断裂韧度JIC均比未经单调拉伸0.3%应变时降低了11%.控制±0.3%全应变的循环加栽500周后,延性断裂韧度JIC比未经单调拉伸0.3%应变时钢的延性断裂韧度JIC提高了15%,产生相反差异的原因还有待于进一步的研究. 相似文献
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The stress-strain curves of confined concrete were obtained based on tests of seven cross-shaped columns confined by stirrups under axial load. The experiment results showed that the strength and deformation of confined concrete can be enhanced effectively by stirrups for cross-shaped columns. Compared with the non-confined concrete, when the stirrup characteristic value is in the range of 0.046--0.230, the confined concrete compressive strengths has an increase of 8%--43%, and the strain corresponding to the peak stress of confined concrete has an increase of 25%-- 195%. According to the test results, the effects of stirrup characteristic and stirrup spacing on the compressive strength and strain of confined concrete were analysed. It is shown that the compressive strength of confined concrete has a linear relationship with the product of stirrup characteristic value and stirrup effective restraint coefficient, and the strain corresponding to the peak stress of confined concrete has a nonlinear relationship with the product of stirrup characteristic value and stirrup effective restraint coefficient. The stress-strain curve equation of confined concrete was proposed for cross-shaped columns, and the calculated curves are in good agreement with the experimental curves. 相似文献
12.
研究了LZ50车轴钢的循环相关特性,循环疲劳特性及循环应力-应变关系。试验结果表明:LZ50车轴钢的循环疲劳特性曲线及循环应力-应变曲线很好地符合双对数线性关系;其循环相关特性表现为先循环软化,稳定后又发生循环硬化,而且循环软化和循环硬化的程度随控制应变的不同而不同。 相似文献
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To study the bending strength of mass concrete under dynamic loading, the pure bending zone of three-graded concrete beam is considered as a three-phase composite composed of matrix, aggregate and interface between them on meso-level. Dynamic constitutive model considering strain-rate strengthening effect and damage softening effect is adopted to describe the cocrete and meso-element's damage. The failure mechanisms of beam under impact loading, triagle wave load, dynamic load coupling with initial static loading were simulated by using displacement-controlled FEM. Furthermore, stress-strain curve of the specimens and their dynamic bending strength were obtained. The results obtained from numerical simulation agreed well with experimental data. 相似文献
14.
Cun-jian MIAO Jin-yang ZHENG Xiao-zhe GAO Ze HUANG A-bin GUO Du-yi YE Li MA 《浙江大学学报(A卷英文版)》2013,14(1):31-37
Cold-stretched pressure vessels from austenitic stainless steels(ASS) are widely used for storage and transportation of liquefied gases,and have such advantages as thin wall and light weight.Fatigue is an important concern in these pressure vessels,which are subjected to alternative loads.Even though several codes and standards have guidelines on these pressure vessels,there are no relevant design methods on fatigue failure.To understand the fatigue properties of ASS 1.4301(equivalents include UNS S30400 and AISI 304) in solution-annealed(SA) and cold-stretched conditions(9% strain level) and the response of fatigue properties to cold stretching(CS),low-cycle fatigue(LCF) tests were performed at room temperature,with total strain amplitudes ranging from -.4% to -.8%.Martensite transformations were measured during the tests.Comparisons on cyclic stress response,cyclic stress-strain behavior,and fatigue life were carried out between SA and CS materials.Results show that CS reduces the initial hardening stage,but prolongs the softening period in the cyclic stress response.Martensite transformation helps form a stable regime and subsequent secondary hardening.The stresses of monotonic and cyclic stress-strain curves are improved by CS,which leads to a lower plastic strain and a much higher elastic strain.The fatigue resistance of the CS material is better than that of the SA material,which is approximately 1?03 to 2?04 cycles.The S-N curve of the ASME standard for ASS is compared with the fatigue data and is justified to be suitable for the fatigue design of cold-stretched pressure vessels.However,considering the CS material has a better fatigue resistance,the S-N curve will be more conservative.The present study would be helpful in making full use of the advantages of CS to develop a new S-N curve for fatigue design of cold-stretched pressure vessels. 相似文献
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This paper proposes a new continuity model for engineering in rock masses and a new schematic method for reporting the engineering of rock continuity.This method can be used to evaluate the mechanics of every kind of medium;and is a new way to determine the mechanical parameters used in engineering design in rock masses.In the numerical simulation,the experimental parameters of intact rock were combined with the structural properties of field rock.The experimental results for orthogonally-jointed rock are given.The results included the curves of the stress-strain relationship of some rock masses,the curve of the relationship between the dimension △ and the uniaxial pressure-resistant strength σc of these rock masses,and pictures of the destructive procedure of some rock masses in uniaxial or triaxial tests,etc.Application of the method to engineering design in rock masses showed the potential of its application to engineering practice. 相似文献
16.
冷弯薄壁型钢梁的滞回性能非线性有限元分析 总被引：1，自引：0，他引：1
在确定冷弯薄壁型简支钢梁应力-应变模型的基础上,采用有限元软件ANSYS对冷弯薄壁型简支钢梁荷载-位移关系进行非线性有限元计算分析。对冷弯薄壁型简支钢梁荷载-位移关系骨架线、弯矩-曲率关系骨架线进行比较分析,主要比较了跨高比、宽厚比对其的影响。 相似文献
17.
运用G1eeb1e1500D热模拟试验机对柱状硼铜（USIBOR1500P）进行热拉伸试验,研究高温下热成形硼钢的变形抗力。首先将试件加热到奥氏体化温度,再以40℃／s冷却速率降到950～550℃,分别以应变速率为0．01、0．1、1／s进行热拉伸试验,获得应力一应变曲线。通过实验结果,分析成形温度、变形程度和应变速率对高温成形件的影响,并利用最小二乘法进行多元线性回归,建立高温下的本构模型。试验结果表明：成形温度和应变速率对变形抗力的影响较为敏感,变形抗力随着成形温度的升高而减小,变形抗力随着变形程度、应变速率的增加而增大。 相似文献
18.
Numerical analysis of ultimate strength of concrete filled steel tubular arch bridges 总被引：8，自引：0，他引：8
INTRODUCTION As a result of the combined effects of the rolled steel tube and the core concrete, Concrete Filled Steel Tubular (CFST) structures can effectively take ad-vantage of these two materials to improve the com-pressive strength and the ductility of the structures. This kind of structure is developing quickly in China and widely used in high-rise structures and bridges. Recently, due to the development of construction projects, numerous studies on CFST structures have been i… 相似文献
19.
The biomechanical behavior of dog's duodenum and jejunum were studied and a formulation of the stress-strain relation is presented
in this paper. The results obtained indicated that the exponential coefficient α and the incremental duodenum of the elastic
modulus are both large than those of the jejunum. It means that the duodenum is more deformable than the jejunum. The experimental
results of this work provide basal data for kinematics study of a robotic endoscope.
Project supported by the National Natural Science Foundation of China (No. 59805017) and the Chinese “863” High Technology
Project of China 相似文献
20.
In order to study the effect of seismic permanent deformation on the safety and stability of earth-rock dam, the permanent deformation is considered as the non-design permanent load, and the stress-strain hysteresis curve is also considered when the earth is under cyclic load. The research work can make the calculation results of plastic collapse more accurate by including the effect of the post-earthquake degree of plastic deformation on the stability of the earth-rock dam, and the dam safety factor decreases from 2.50 to 1.90 after the magnitude-8 earthquake. Moreover, the research work will also improve the design of the earth-rock dam under abnormal operating conditions. 相似文献