Akio Tange

Static and dynamic properties of unidirectional CFRP laminates with flexible interphase

In this study, a flexible interphase than matrix resin is studied. The fabrication method of unidirectional CFRP laminates with flexible fiber/matrix interphase has been established. The influence of the flexible interphase thickness on the flexural modulus and strength are experimentally investigated. The influence on the vibration properties are also investigated. It has been concluded that the flexible interphase with the optimized thickness could improve both the static and dynamic properties.

Eigenfrequency Analysis Method For Single-lapAdhesive Joints Of CFRP Laminates

The purpose of this study is to propose a new numerical modeling of single-lap joints of CFRP laminated composites. The eigenvibration mode is always three-dimensional behavior deformation which includes in-plane and out-plane deformations. This indicates that the finite element analysis requires threedimensional solid element. In case that the adherend plane structure is modeled by the conventional solid element, the huge elements and huge solution time are unavoidable. Therefore, we proposed the new numerical model in this study. This model is construction of orthtropic-shell element and beam element, which represent adherend and adhesive, respectively. Shell elements are connected with beam elements in the thickness direction to express adhesive layer. The space between shell and beam elements is combined by rigid link to the correspond the beam elements length to the real adhesive thickness. Using this model, the eigenvibration analysis of canti-levered CFRP single-lap joints structure were performanced. Influences of adhesive and adherend properties and adherend thickness upon eigenfrequency are also discussed. Hoop positions of the 1st and 2nd eigenvibration modes of CFRP adhesive joints are an free edge of specimen and the adhesive, respectively. In particular, it is confirmed that the 2nd eigenfrequency depends on shear deformability in adhesive layer. Transactions on Engineering Sciences vol 21,

Modified Quasi-three-dimensional 4-pointBending Simulation Method For CFRPCylindrical Tube

The damage propagation of a CFRP cylindrical tube subjected to 4-point bending load was investigated. A numerical simulation using a quasi-threedimensional model is attempted. The quasi-three-dimensional model is constructed of both shell elements and beam elements which represent fiber and matrix, respectively. The damage propagation analyses of three types have been performed. As a result, it is confirmed that the numerical simulation using the quasi-three-dimensional model is effective for predicting the damage propagation behaviours.

Reliability Engineering. Eigenfrequency Analysis Method of Sandwich Injection Moldings.

The purpose of this study is to propose a new numerical modeling of sandwich injection moldings, in which two kinds of materials are sequentially injected from one gate with a time lag. Using this molding method, the skin and core layers can be set in same injection, respectively. The materials of excellent mechanical properties can be produced by this method in comparison with the uniform plastic. The numerical proposed model in this study consists of shell and beam elements, corresponding to skin and core layers, respectively. The validity of the new numerical model for the eigenvibration analysis of sandwich injection moldings is checked through comparisons with experimental results. Using this model, influences of skin layer properties and core area ratios upon eigenfrequency are discussed. The results indicate that the validity of the new numerical model was verified through comparisons with experimental results.