Papers by Keyword: Core Thickness

Abstract: This study explored the feasibility of flexural performance of composite sandwich material composed of various low density polyurethane foam core thickness sandwiched between GFRP skins. The mechanical behaviour of this material was assessed by carrying out a flexural testing. Each spesimen had a nominal dimensions of 110 mm x 30 mm x (c + 4 mm). These spesimens with various core thickness (c) of 2 mm. 5 mm. and 8 mm were then tested in three point bending according to ASTM C 393-00. This study revealed that. by incorporating the thickest core ( 8 mm ) . the bending strength decreases by 42.3 % compared to 5 mm core and it further decreases by 72.6 % compared to 2 mm core. The material stiffness showed positive trend for the thickest core (8 mm). it increases by 53.1 % and 78.1 % compared to 5 mm core and 2 mm core respectively. Low shear modulus of polyurethane foam core contributed to the low bending strength of composite sandwich material with 8 mm core. This was further confirmed by failure analysis under optical microscope which revealed that core shear failure was the dominant failure mechanism for 8 mm core. Meanwhile the dominant failure mechanism for 2 mm core and 5 mm core was microbuckling which confirm the high modulus of GFRP skin. The material stiffness was affected by the high modulus of GFRP skin and the core thickness.

Abstract: Considering core thickness is important issue to performance of exterior frame and core hybrid structure in high-rise buildings, seismic response analysis is conducted by response spectrum method for finite element models with different core thickness. The optimization design of core thickness of hybrid Structures on the basis of the seismic response is studied, the core thicknesses are chosen as design variables, the objective function about core volume is adopted, some specification requirements such as deformation, the ratio of lateral stiffness to gravity, storey shear to gravity, storey shear of exterior frame, axial compression ratio of column and wall limb, bearing capacity of structural member and core construction are regarded as restricting conditions, the optimal mathematical model is established for reflecting integrity dynamic properties of hybrid structure. The ANSYS software is used for optimizing tool, the hybrid structures optimization design are made through different initial values for verifying convergence of optimization method, the optimal result show that the performances of hybrid structure are improved, the internal forces are reduced and the ratios of inner force born by exterior frames are increased in the optimal scheme.