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Prediction of cyclic large plasticity for prestrained structural steel using only tensile coupon tests

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Frontiers of Structural and Civil Engineering 2013年第4期7卷 466-476页

作者： Liang-Jiu JIA Tsuyoshi KOYAMA Hitoshi KUWAMURA Department of Architecture School of Engineeringthe University of TokyoTokyo 113-8656Japan

Cold-formed steel members,which experience complicated prestrain histories,are frequently applied in structural engineering.This paper aims to predict Cyclic plasticity of structural steels with tensile and compressive prestrain.Monotonic and cyclic tests on hourglass specimens with tensile and compressive prestrain are conducted,and compared with numerical simulations using the Chaboche model.Two approaches are taken in the simulation.The first requires only the monotonic tensile test data from the prestrained steels,and the second requires both the monotonic tensile test data from the virgin steel and the prestrain histories.The first approach slightly overestimates the compressive stress for specimens with tensile prestrain,while the second approach is able to accurately predict the Cyclic plasticity in specimens with tensile and compressive prestrain.

关键词： Cyclic plasticity prestrain Chaboche model mild steel

A MICROSTRUCTURE-BASED ANALYSIS FOR Cyclic plasticity OF DUAL-PHASE PEARLITIC RAIL STEELS

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Acta Mechanica Solida Sinica 2001年第4期14卷 334-343页

作者： Peng Xianghe Chang Jian Chongqing Univ Dept Engn Mech Chongqing 400044 Peoples R China

Based on the assumption that a representative element of apearlitic steel is an aggregate of numerous spherical pearliticcolonies with randomly distributed orientations, and that each colonyis com- posed of many parallel fine lamellas of ferrite andcementite, a description for the dual-phase pearlitic steel isobtained by making use of a microstructure-based constitutiveequation for a single dual-phase pearlitic colony and the Hill'sself-consistent scheme. The elastoplastic response of dual-phasepearlitic steel BS11 subjected to asymmetrically cyclic loading isanalyzed, and a comparison with the experimental results showssatisfacto- ry agreement. The non-proportional Cyclic plasticity ofBS11 is also analyzed, in which stress develops along a semi-circlein a biaxial tension/compression and shear stress plane, as istypically experienced by the sur- face elements in rolling andsliding contact.

关键词： pearlitic steel lamellar dual-phase material Hill's self-consistent scheme Cyclic plasticity

Damage localization effects of the regeneratively-cooled thrust chamber wall in LOX/methane rocket engines

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Chinese Journal of Aeronautics 2018年第8期31卷 1667-1678页

作者： Jiawen SONG Bing SUN School of Astronautics Beihang University

To investigate the damage localization effects of the thrust chamber wall caused by combustions in LOX/methane rocket engines, a fluid-structural coupling computational methodology with a multi-channel model is developed to obtain 3-demensioanl thermal and structural responses.Heat and mechanical loads are calculated by a validated finite volume fluid-thermal coupling numerical method considering non-premixed combustion processes of propellants. The methodology is subsequently performed on an LOX/methane thrust chamber under cyclic operation. Results show that the heat loads of the thrust chamber wall are apparently non-uniform in the circumferential direction. There are noticeable disparities between different cooling channels in terms of temperature and strain distributions at the end of the hot run phase, which in turn leads to different temperature ranges, strain ranges, and residual strains during one cycle. With the work cycle proceeding, the circumferential localization effect of the residual strain would be significantly enhanced. A post-processing damage analysis reveals that the low-cycle fatigue damage accumulated in each cycle is almost unchanged, while the quasi static damage accumulated in a considered cycle declines until stabilized after several cycles. The maximum discrepancy of the predicted lives between different cooling channels is about 30%.

关键词： Cyclic plasticity Damage Heat transfer Regenerative cooling Rocket engine Service life Thrust chamber

Experimental Study on the Uniaxial cyclic Deformation of 25CDV4.11 Steel

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Journal of Materials Science & Technology 2005年第1期21卷 5-9页

作者： Guozheng KANG, Qianhua KAN and Juan ZHANGDepartment of Applied Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, ChinaProf., Ph.D., Dept. of Appl. Mech. and Eng. Southwest Jiaotong Univ. Chengdu 610031 China

The strain cyclic characteristics and ratcheting behavior of 25CDV4.11 steel were studied by the experiments under uniaxial cyclic loading with relatively high cyclic number and at room temperature. The cyclic hardening/softening feature of the material was first observed under the uniaxial strain cycling with various strain amplitudes. Then, the ratcheting behavior of the material was researched in detail, and the effects of stress amplitude and mean stress on the ratcheting were discussed under uniaxial asymmetrical stress cycling. Comparing with the experimental results of SS316L stainless steel, it is concluded that the material exhibits remarkable cyclic softening feature, and then a special ratcheting behavior is caused. Some conclusions useful to establish corresponding constitutive model are obtained.

关键词： Ratcheting cyclic softening Cyclic plasticity Uniaxial loading

Experimental Study on Non-proportional Multiaxial Strain cyclic Characteristics and Ratcheting of U71Mn Rail Steel

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Journal of Materials Science & Technology 2002年第1期18卷 13-16页

作者： Guozheng KANG, Qing GAO, Lixun CAI, Yafang SUN and Xianjie YANGDepartment of Applied Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China [ Manuscript received December 4, 2000, in revised form February 20, 2001] Dept. of Appl. Mech. and Eng. Southwest Jiaotong Univ. Chengdu 610031 China

An experimental study was carried out on the strain cyclic characteristics and ratcheting of U71Mn rail steel subjected to non-proportional multiaxial cyclic loading. The strain cyclic characteristics were researched under the strain-controlled circular load path. The ratcheting was investigated for the stress-controlled multiaxial circular, elliptical and rhombic load paths with different mean stresses, stress amplitudes and their histories. The experiment shows that U71Mn rail steel features the cyclic non-hardening/softening, and its strain cyclic characteristics depend greatly on the strain amplitude but slightly on its history. However, the ratcheting of U71Mn rail steel depends greatly not only on the values of mean stress and stress amplitude, but also on their histories. In the meantime, the shape of load path and its history also apparently influence the ratcheting. The ratcheting changes with the different loading paths.

关键词： U71 Mn steel Ratcheting Cyclic plasticity Non-proportional load

THE STRAIN cyclic CHARACTERISTICS AND RATCHETING OF U71Mn RAIL STEEL UNDER UNIAXIAL LOADING

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 893-900页

作者： G.Z. Kang Q. Gao, X.J.Yang and Y.F. Sun(Department of Applied Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, China) Southwest Jiaotong Univ Chengdu China

An experimental study was carried out of the cyclic behavior of U71Mn rail steel subjected to uniaxial strain and stress. The effects of cyclic struin amplitude, mean struin,strain loading rate and their histories on the strain cyclic characteristics were studied.Under the asymmetrical stress cycling, the effects of stress amplitude, mean stress,stress loading rate and their histories on the ratcheting were analyzed. The interaction between strain cycling and stress cycling was also discussed. It is shown that either the cyclic characteristics under strain cycling or the ratcheting under asymmetrical stress cycling depends not only on the cumnt loading state, but also on the previous loading history. Some significant results are obtained.

关键词： Cyclic plasticity ratcheting U71Mn rail steel uniaxial loading