| 2 | A NEW METHOD FOR MEASURING LONG-TERMCREEP DEFORMATION IN A SMALL REGION显示文摘Creep deformation localization is generally found in structures at high temperamture,typically in weldments. As the heat affected zone (HAZ) in a weldment is very narrow, deformation in HAZ region can hardly be measured by conventional displacement gauge. A new method for measuring long-term local creep deformation was developed by quartz optical fiber and technique of digital image analysis. The creep deformations of base metal, weld metal and HAZ in weldments are thereby determined with crossweld specimens. | J.M.Gong S.T.Tu J.Xia X.Ling | 1998 | Acta Metallurgica Sinica(English Letters)1998，11，6： | 1 |
| 3 | Dynamic Impact of High-Density Aluminum Foam显示文摘High-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise because the hydrostatic pressure can reach more than 30 MPa.In this paper,instead of using tri-axial tests,we proposed three easier tests-tension,compression and shear to obtain the parameters of constitutive model(the Deshpande-Fleck model).To verify the constitutive model both statically and dynamically,we carried out addi-tional triaxial tests and direct impact tests,respectively.Based on the derived model,we performed finite element simulation to study the impact response of the present foam.By dimensional analysis,we proposed an empirical equation for a non-dimensional impact time the impact time divided by the time required for plastic wave travelling from the impact surface to the bottom surface,to det ermine the deformation charac teristic of the aluminum foam after impact.For the case with t_(d)≤1,the deformation tends to exhibit a shock-type characteristic,while for the case with t_(d)>5,the deformation tends to exhibit an upsetting-type characteristic. | Q.Peng J.Xie H.S.Ma X.Ling X.Liu Y.G.Wei | 2022 | Acta Mechanica Solida Sinica2022，35，2： | 0 |
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