Shohei Kasahara

Bio: Shohei Kasahara is an academic researcher from Tokyo University of Science. The author has contributed to research in topics: Fibre-reinforced plastic. The author has an hindex of 1, co-authored 1 publications receiving 6 citations.

Evaluation of interface properties of carbon fiber/resin using the full atomistic model considering the electric charge state

Abstract: Evaluation of interface strength is important in composite material design such as carbon fiber reinforced plastic. Molecular simulation, which considers aspects such as chemical structure, can be ...

Recent advances of interphases in carbon fiber-reinforced polymer composites: A review

Abstract: Carbon fiber reinforced polymer (CFRP) have excellent properties such as light weight, high strength, high modulus and high temperature resistance, and have wide application prospect in the fields of national defense, aerospace and high-end civilian products. Various methods have been exploited to modify the CF to increase the surface activity, roughness and wettability , so that the interfacial adhesion between fiber and matrix could be improved for better mechanical properties, which is helpful to meet the needs of more fields for high-performance CFRP. In this review, the recent progress of CF surface modification methods and their reinforcing effects on composites are mainly summarized. Finally, some issues of CFRP are discussed and the future trends of interfacial reinforcement research are prospected.

Enhancing mechanical strength of carbon fiber-epoxy interface through electrowetting of fiber surface

Abstract: The interfacial shear strength between carbon fiber and polymer matrices plays a critical role in bulk mechanical performances of carbon fiber-reinforced polymer composites. However, finding simple and effective methods for modulating the interfacial adhesion remains challenging even after over a decade of research and development. Herein, a novel method based on electrically-assisted wetting technique was developed to strengthen the interfacial adhesion between carbon fiber and polymer matrix. The results indicated the polymer completely infiltrated the small grooves on the fiber surface under applied external electric field during the curing process, leading to the formation of conformal contact interface. The interfacial properties were characterized by utilizing the microdroplet debonding and single fiber fragmentation tests. It is found that the as-prepared composites exhibit a maximum increased interfacial shear strength (IFSS) reaching up to 119.69 MPa, a value 81.02% higher than that of the original fiber-based composites. The reinforcement mechanism was ascribed to the improved wettability and mechanical interlock effect induced by the applied electrical stimulus which was supported by dynamic simulation of two-phase flow. In sum, the suggested simple, facile, and environmentally friendly strategy can effectively regulate the interfacial load transfer capacity, thereby suitable for the optimal design of fiber-reinforced composites.

Molecular dynamics simulation for the quantitative prediction of experimental tensile strength of a polymer material

Abstract: This paper presents a quantitative method for predicting the experimental value of the tensile strength of a polymer material by using molecular dynamics (MD) simulation. Because the tensile strength obtained by MD simulation is almost always higher than the experimental value, a solution is suggested in the present study. Several simulations varying simulation volumes (i.e., number of molecules) and tensile loading speeds (i.e., strain rate) were implemented; the results confirmed that the tensile strength decreases with increasing simulation volume and decreasing strain rate. Firstly, strength as a function of the simulation volume was determined based on Weibull statistics and then the relationship was extrapolated to a much higher number of molecules, which was equivalent to a real specimen. Secondly, the relationship between the tensile strength and strain rate was determined and it was extrapolated to match the strain rate in actual experiments. Consequently, a predicted strength was close to the experimental result.

A Possibility for Quantitative Detection of Mechanically-Induced Invisible Damage by Thermal Property Measurement via Entropy Generation for a Polymer Material

Abstract: Entropy generation from a mechanical and thermal perspective are quantitatively compared via molecular dynamic (MD) simulations and mechanical and thermal experiments. The entropy generation values regarding mechanical tensile loading—which causes invisible damage—of the Polyamide 6 (PA6) material are discussed in this study. The entropy values measured mechanically and thermally in the MD simulation were similar. To verify this consistency, mechanical and thermal experiments for measuring entropy generation were conducted. The experimentally obtained mechanical entropy was slightly less than that calculated by MD simulation. The thermal capacity is estimated based on the specific heat capacity measured by differential scanning calorimetry (DSC), applying the assumed extrapolation methods. The estimated entropy generation was higher than the aforementioned values. There is a possibility that the entropy-estimating method used in this study was inappropriate, resulting in overestimations. In any case, it is verified that entropy increases with mechanical loading and material invisible damage can be qualitatively detected via thermal property measurements.