Light weight high performance sandwich composite structures have been used extensively in various load bearing applications.Experiments have shown that the indentation significantly reduces the load bearing capacity o...Light weight high performance sandwich composite structures have been used extensively in various load bearing applications.Experiments have shown that the indentation significantly reduces the load bearing capacity of sandwiched beams.In this paper,the indentation behavior of foam core sandwich beams without considering the globally axial and flexural deformation was analyzed using the principle of virtual velocities.A concisely theoretical solution of loading capacity and denting profile was presented.The denting load was found to be proportional to the square root of the denting depth.A finite element model was established to verify the prediction of the model.The load-indentation curves and the profiles of the dented zone predicted by theoretical model and numerical simulation are in good agreement.展开更多
The quasi-static indentation behavior of sandwich beams with a metal foam core was investigated. An analytical model was developed to predict the large deflections of indention of the sandwich beams with a metal foam ...The quasi-static indentation behavior of sandwich beams with a metal foam core was investigated. An analytical model was developed to predict the large deflections of indention of the sandwich beams with a metal foam core subjected to a concentrated loading. The interaction of plastic bending and stretching in the local deformation regions of the face sheet was considered in the analytical model. Moreover, the effects of the shear strength of the foam core on the indentation behavior were discussed in detail. The finite element simulations were preformed to validate the theoretical model. Comparisons between the analytical predictions and finite element results were conducted and good agreement was achieved. The results show that the membrane force dominates indentation behavior of the sandwich beams when the maximum deflection exceeds the thickness of the face sheet.展开更多
The good quality CuInGaSe2 (CIGS) thin film solar cells were fabricated on molybdenum metal coated soda lime glass substrate. Three-stage co-evaporation method was utilized for the fabrication of high quality p-type C...The good quality CuInGaSe2 (CIGS) thin film solar cells were fabricated on molybdenum metal coated soda lime glass substrate. Three-stage co-evaporation method was utilized for the fabrication of high quality p-type CIGS thin film absorber layer. Further, n-type CdS layer, high resistive intrinsic ZnO layer and transparent conducting AlZnO layers were fabricated by CBD method and vacuum sputtering methods. We made three various top metal sandwich grid patterns, i.e. Al, Al/Cu and Cu/Al which were utilized to investigate the metal sandwich layer oriented efficiency enhancement superiority on CuInGaSe2 thin film solar cells. The investigated specific CIGS solar cell device efficiency with respect to various top metal grid sandwich patterns is presented and discussed.展开更多
基金supported by the National Natural Science Foundation of China(90916026,10532020 and 10672156)the Chinese Academy of Sciences(KJCX2-EW-L03)
文摘Light weight high performance sandwich composite structures have been used extensively in various load bearing applications.Experiments have shown that the indentation significantly reduces the load bearing capacity of sandwiched beams.In this paper,the indentation behavior of foam core sandwich beams without considering the globally axial and flexural deformation was analyzed using the principle of virtual velocities.A concisely theoretical solution of loading capacity and denting profile was presented.The denting load was found to be proportional to the square root of the denting depth.A finite element model was established to verify the prediction of the model.The load-indentation curves and the profiles of the dented zone predicted by theoretical model and numerical simulation are in good agreement.
基金Projects(11102146,11372235,11272246,11021202,11002107)supported by the National Natural Science Foundation of ChinaProject(2011CB610301)supported by the National Basic Research Program of ChinaProject supported by the Fundamental Research Funds for the Central Universities,China
文摘The quasi-static indentation behavior of sandwich beams with a metal foam core was investigated. An analytical model was developed to predict the large deflections of indention of the sandwich beams with a metal foam core subjected to a concentrated loading. The interaction of plastic bending and stretching in the local deformation regions of the face sheet was considered in the analytical model. Moreover, the effects of the shear strength of the foam core on the indentation behavior were discussed in detail. The finite element simulations were preformed to validate the theoretical model. Comparisons between the analytical predictions and finite element results were conducted and good agreement was achieved. The results show that the membrane force dominates indentation behavior of the sandwich beams when the maximum deflection exceeds the thickness of the face sheet.
文摘The good quality CuInGaSe2 (CIGS) thin film solar cells were fabricated on molybdenum metal coated soda lime glass substrate. Three-stage co-evaporation method was utilized for the fabrication of high quality p-type CIGS thin film absorber layer. Further, n-type CdS layer, high resistive intrinsic ZnO layer and transparent conducting AlZnO layers were fabricated by CBD method and vacuum sputtering methods. We made three various top metal sandwich grid patterns, i.e. Al, Al/Cu and Cu/Al which were utilized to investigate the metal sandwich layer oriented efficiency enhancement superiority on CuInGaSe2 thin film solar cells. The investigated specific CIGS solar cell device efficiency with respect to various top metal grid sandwich patterns is presented and discussed.
