共查询到20条相似文献,搜索用时 11 毫秒
1.
内爆炸加载条件下圆筒的膨胀、破裂规律研究 总被引:7,自引:0,他引:7
以经典热粘塑性本构关系 (John Cook本构关系和Powerlaw本构关系 )为基础 ,建立了更适当表征材料特征的新的、解耦的本构关系。采用SHPB(分离式霍普金森杆 )技术测定了常用弹箭材料 35CrMnSiA的不同应变率下的应力、应变关系 ,并采用拟合的方法确定了本构方程中的材料常数。与高速摄影技术测得的径向位移函数及圆筒材料的损伤演化方程相结合 ,建立了控制内爆炸加载圆筒膨胀 ,直至破裂的完备方程组 ,完成了内爆炸加载圆筒问题的数值模拟 ,计算结果与以往有关箭弹材料圆筒膨胀的实验结果符合较好。 相似文献
2.
Interfacial debonding of coated-fiber-reinforced composites under tension-tension cyclic loading 总被引:8,自引:0,他引:8
A new degradation function of the friction coefficient is used. Based on the double shear-lag model and Paris formula, the
interfacial damage of coated-fiber-reinforced composites under tension-tension cyclic loading is studied. The effects of strength
and thickness of the coating materials on the debond stress, debond rate as well as debond length are simulated.
The subject supported by the National Natural Science Foundation of China (No.59778034), Teaching and Research Award Program
for Outstanding Young Teachers in Higher Education Institutions of MOE, China and The Hong Kong Polytechnic University (G-S737) 相似文献
3.
Relations are proposed for the determination of the stress-strain state, strength, and life of butt welds with mild and hard
interlayers under cyclic elastoplastic tension-compression. The accumulation of cyclic and quasistatic damages is determined
with allowance for the redistribution of the cyclic elastoplastic strains and hardness of the stress state due to changes
in the cyclic properties of separate regions of welds. The theoretical distribution of cyclic strains and the durability of
welds under cyclic elastoplastic loading are supported by experimental data
__________
Translated from Prikladnaya Mekhanika, Vol. 44, No. 2, pp. 29–38, February 2008. 相似文献
4.
Fatigue damage model for bridge under traffic loading: application made to Tsing Ma Bridge 总被引:2,自引:0,他引:2
A fatigue damage model is developed to account for the damage accumulation process in bridges subjected to in-field traffic loading. Continuous damage mechanics (CDM) is applied to formulate damage kinetic constitutive equations. On-line strain gauge measurements are then made on the orthotropic steel deck structure of the Tsing Ma Bridge, an essential portion of the transport network for the Hong Kong airport. Fatigue life prediction analyses are then made. The results agree well with those obtained by the tests. 相似文献
5.
6.
A constitutive model for cyclic plasticity is briefly outlined. Then the model is implemented in a finite element code to predict the response of cyclic loaded structural components such as a double-edge-notched plate, a grove bar and a nozzle in spherical shell. Comparision with results from other theories and experiments shows that the results obtained by using the present model are very satisfactory.The Project Supported by National Natural Science Foundation of China. 相似文献
7.
两级载荷下复合材料层板疲劳与寿命预测 总被引:4,自引:0,他引:4
研究了复合材料层板疲劳过程中的累积应变演化规律,建立了以累积应变为基础的非线性积累损伤法则,实验结果表明:文中提出的累积应变方法能够较好地反映加载次序效应,准确地预测了复合材料层板在两级载荷下的疲劳寿命。 相似文献
8.
9.
Some mechanical properties exhibit a very strong dependence upon temperature; these evolutions can be properly analyzed by the steady state response in cyclic loading. To relate experimental conditions to thermomechanical characteristics, the existence and the stability of steady state solutions are studied for cylinders submitted to cyclic compression. The material, considered as rigid viscoplastic, is modeled by a non-Newtonian temperature dependent viscous law. Closed form solutions are obtained in the framework of a large deformation theory by neglecting thermal expansion and inertia effects. Steady state regime is analyzed. The stress versus strain rate response and the temperature distribution are established as functions of the geometry of the cylinder, the loading characteristics and the material parameters. The stability of steady state solutions is analyzed with use of a linear perturbation scheme.Received: 4 July 2002, Accepted: 5 August 2004, Published online: 24 February 2005PACS:
46.15.Ff, 83.60.St
Correspondence to: F. Dinzart 相似文献
10.
A two-surface model describing ratchetting behaviors and transient hardening under nonproportional loading 总被引:2,自引:0,他引:2
A new superposed rule of Mroz's kinematic hardening rule and Ziegler's kinematic hardening rule based on two-surface model
is proposed in the paper. Some experimental results on ratchetting of 2014-T6 aluminum alloy are predicted very well under
multiaxial loading. In addition the conformability of the model is discussed for transient cyclic hardening under two kinds
of nonproportional cyclic loading paths, i.e. square and rhombic path.
The project supported by the National Natural Science Foundation of China 相似文献
11.
一种新型的宽带随机谱下疲劳寿命计算模型的建立与分析 总被引:1,自引:0,他引:1
通过严密的数学推导和具体的数值分析,建立了一种新型的宽带随机载荷谱下疲劳寿命计算模型,数值计算表明,本模型较国际上已有的几种有代表性的近似计算模型有更大的适应范围和更高的精度。 相似文献
12.
V. P. Golub V. I. Krizhanovskii A. D. Pogrebnyak 《International Applied Mechanics》2004,40(11):1281-1289
A new method of plotting limit stress diagrams is set forth. The method is based on the hypothesis of unified limit diagram invariant to the number of cycles to failure. The unified diagram is given by a transcendental power function whose exponent is considered an additional material constant characterizing the sensitivity of the material to cycle asymmetry (stress ratio). The equations derived on the basis of this function encompass all forms of limit stress diagrams, including convex, nearly rectilinear, and concave ones. The method is tested for a wide range of metallic and composite materials subjected to asymmetric tension-compression, bending, and torsion.Translated from Prikladnaya Mekhanika, Vol. 40, No. 11, pp. 106–116, November 2004.This revised version was published online in April 2005 with a corrected cover date. 相似文献
13.
14.
15.
V. A. Gorokhov S. A. Kapustin Yu. A. Churilov 《Journal of Applied Mechanics and Technical Physics》2017,58(3):461-468
This paper presents the results of a finite-element study of elastic-plastic deformation and damage accumulation in structural materials under various cyclic loading conditions. Material behavior is described by the relations of damage mechanics using thermoplastic model which takes into account the plastic deformation of material under cyclic loading and the kinetic equations of the energy theory of damage accumulation. The basic laws of plastic deformation and development of damage in materials under hard, soft, symmetric, and asymmetric low-cycle loading are established. 相似文献
16.
利用MTS 815电液伺服岩石实验系统进行上限应力为80%、85%、90%、95%单轴抗压强度的大理岩单轴压缩循环加卸载实验,每种上限应力条件分别设置20、40、60、80次循环。再利用分离式Hopkinson压杆对损伤岩样进行动力学实验。分析了循环加卸载上限应力及循环次数对大理岩塑性应变的影响,揭示了大理岩动态力学参数和破碎吸收能随损伤变量的演化规律。实验结果表明:塑性应变与循环次数呈正相关,且上限应力越大,塑性应变趋于稳定所需的循环次数也会增大;动态单轴抗压强度、动态弹性模量随损伤变量增加呈指数衰减;破碎吸能占比以损伤变量D=0.343为临界点分为两个阶段,D<0.343时,破碎吸能占比稳定在10%左右,数值约为13 J,当D>0.343时破碎吸能占比随损伤变量增加不断增大。研究结果可为岩体工程的设计、施工及支护参数的选取提供参考。 相似文献
17.
采用
18.
The fatigue life prediction for components is a difficult task since many factors can affect the final fatigue life. Based on the damage evolution equation of Lemaitre and Desmorat, a revised two-scale damage evolution equation for high cycle fatigue is presented according to the experimental data, in which factors such as the stress amplitude and mean stress are taken into account. Then, a method is proposed to obtain the material parameters of the revised equation from the present fatigue experimental data. Finally, with the utilization of the ANSYS parametric design language (APDL) on the ANSYS platform, the coupling effect between the fatigue damage of materials and the stress distribution in structures is taken into account, and the fatigue life of specimens is predicted. The outcome shows that the numerical prediction is in accord with the experimental results, indicating that the revised two-scale damage evolution model can be well applied for the high cycle fatigue life prediction under uniaxial loading. 相似文献
19.
The fatigue failure of a thin infinite center-cracked plate under completely reversed uniaxial loading is considered. A two-stage
fatigue crack model including the incubation and crack propagation stages is constructed. The stress distribution in the vicinity
of the crack tip is described using the concept of a conventional elastic crack. The crack-tip plastic zone is simulated by
a Dugdale thin plastic zone, and the condition for the movement of the failure front is given by criteria of damage mechanics.
It is shown that the fatigue crack growth rate in perfectly plastic materials with a plastic zone of constant length is a
power-law function of the stress intensity factor range. This relationship is quadratic when the length of the plastic zone
is not constant
Published in Prikladnaya Mekhanika, Vol. 41, No. 12, pp. 116–127, December 2005. 相似文献