Faculty Profiles - YOSHIMURA Akinori

Papers - YOSHIMURA Akinori

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High-Velocity Impact Damage in CFRP Unidirectional and Cross-Ply Laminates Reviewed

OGI Keiji, TANAKA Takaaki, YASHIRO Shigeki, YOSHIMURA Akinori

Journal of the Society of Materials Science, Japan Vol. 60 ( 5 ) page： 418-424 2011

Language：Japanese Publishing type：Research paper (scientific journal)

This paper aims at characterizing the high-velocity impact damage behavior in carbon fiber reinforced plastic (CFRP) unidirectional (UD) and cross-ply (CP) laminates. First, the surface and internal damages of CFRP plates impacted at a velocity of 200 and 430m/s were observed by using optical microscopy together with radiography. Next, dynamic finite element analysis was performed to simulate the damage process. Cohesive elements were introduced to express the delamination and splitting cracks while the maximum stress fracture criteria were employed to express the intralaminar failure. Finally, the simulations were compared with the experiment results to verify the reasonability of the analysis. The damage process in both laminates was as follows : 1. A crater accompanied by splitting cracks is generated at the impact point on the front surface while splitting cracks due to bending are observed on the back surface. 2. Cone-shaped matrix cracking is observed in the UD laminate while few matrix cracking is generated in the CP laminate. 3. The shape of the delamination in the UD and CP laminates is a galaxy and a circle, respectively. Delamination size is larger in the CP laminate than in the UD laminate, which results in higher energy absorption capability in the CP laminate. Simulations are in qualitatively good agreement with the experiment results.

DOI： 10.2472/jsms.60.418

Damage Growth Analysis in Particle-Reinforced Composite Using Cohesive Element Reviewed

Akinori Yoshimura, Tomonaga Okabe

ADVANCED COMPOSITE MATERIALS Vol. 20 ( 6 ) page： 569 - 583 2011

Language：English Publishing type：Research paper (scientific journal) Publisher：VSP BV

In this paper, a simple numerical analytical method is proposed for simulating crack extension in a particulate-reinforced composite material. The numerical method is based on finite element analysis with the homogenization method, where crack extension is expressed using embedded cohesive elements. We first present the formulation of the numerical model and verify the model's validity by comparing the simulated crack extension with the linear fracture mechanics. Next we simulate damage extension for a composite reinforced with spherical particles. We consider the cracks in the particles and on particle-matrix interfaces. The analytical results reveal the effect of crack extension on the macroscopic material properties of the composite. The particle crack extends unstably and sharply decreases the tangent modulus of the material, irrespective of the initial flaw size. In contrast, the interfacial crack invariably grows stably and decreases the tangent modulus gradually. (C) Koninklijke Brill NV, Leiden, 2011

DOI： 10.1163/156855111X610406

Web of Science

Scopus

平織CFRP積層板に加工されたネジ穴の引張り強さ

小笠原俊夫, 吉村彰記, 紙田徹

JAXA research and development memorandum Vol. 11 ( 002 ) page： 1-11 2011

Damage characterization in thin-ply composite laminates under out-of-plane transverse loadings Reviewed

Tomohiro Yokozeki, Akiko Kuroda, Akinori Yoshimura, Toshio Ogasawara, Takahira Aoki

COMPOSITE STRUCTURES Vol. 93 ( 1 ) page： 49 - 57 2010.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

Composite laminates with thin-ply layers are expected to exhibit superior damage resistance to the standard composite laminates. This study investigated the damage characteristics of carbon fiber/toughened epoxy thin-ply laminates subjected to transverse loadings. Quasi-isotropic laminates were prepared using both standard prepregs and thin-ply prepregs in order to examine the effect of ply thickness on the damage accumulation processes. Clear difference on damage accumulation process between standard laminates and thin-ply laminates was identified; fiber fractures were susceptible to formation in thin-ply laminates. Finally, the reason of the difference on damage process was investigated using finite element analyses, and it was clarified that the accumulated delamination position has a significant effect on the fiber fractures during the indentation. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.compstruct.2010.06.016

Web of Science

Scopus

Coupled thermal-electrical analysis for carbon fiber/epoxy composites exposed to simulated lightning current Reviewed

Toshio Ogasawara, Yoshiyasu Hirano, Akinori Yoshimura

COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING Vol. 41 ( 8 ) page： 973 - 981 2010.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

A coupled thermal-electrical analysis of carbon fiber reinforced polymer composites (CFRP) exposed to simulated lightning current was conducted in order to elucidate the damage behavior caused by a lightning strike with the numerical results being compared to experimental results. Based on the experimental results and a preliminary analysis, the specific mechanism of electrical conduction through the thickness direction of CFRP following thermal decomposition was revealed to be a key parameter for accurate numerical simulation. In particular, assuming the electrical conductivity in the thickness direction to be linear with respect to temperature in the range from the epoxy decomposition temperature to carbon sublimation temperature produced reasonable numerical results. The delamination area and damage depth were estimated from numerical results and thermal decomposition behavior of CFRP with the estimated damage area agreeing qualitatively with the experimental results. Numerical results suggest that Joule heat generation significantly influences lightning strike damage. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.compositesa.2010.04.001

Web of Science

Scopus

Experimental characterization of high-speed impact damage behavior in a three-dimensionally woven SiC/SiC composite Reviewed

K. Ogi, T. Okabe, M. Takahashi, S. Yashiro, A. Yoshimura, T. Ogasawara

Composites Part A: Applied Science and Manufacturing Vol. 41 ( 4 ) page： 489-498 2010.4

A Numerical Simulation of Time-Dependent Interface Failure Under Shear and Compressive Loads in Single-Fiber Composites Reviewed

Jun Koyanagi, Akinori Yoshimura, Hiroyuki Kawada, Yuichiro Aoki

APPLIED COMPOSITE MATERIALS Vol. 17 ( 1 ) page： 31 - 41 2010.2

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

We performed a numerical simulation of a time-dependent interfacial failure accompanied by a fiber failure, and examined their evolution under shear and compressive loads in single-fiber composites. The compressive load on the interface consists of Poisson's contraction for matrix resin subjected to longitudinal tensile load. As time progresses, compressive stress at the interface in the fiber radial direction relaxes under the constant longitudinal tensile strain condition for the specimen, directly causing the relaxation of the interface frictional stress. This relaxation facilitates the failure of the interface. In this analysis, a specific criterion for interface failure is applied; apparent interfacial shear strength is enhanced by compressive stress, which is referred as quasi-parabolic criterion in the present study. The results of the stress recovery profile around the fiber failure and the interfacial debonding length as a function of time simulated by the finite element analysis employing the criterion are very similar to experimental results obtained using micro-Raman spectroscopy.

DOI： 10.1007/s10443-009-9118-2

Web of Science

Scopus

Evaluation of Gas Permeability of CFRP Laminates under Cyclic Loadings Reviewed

YOKOZEKI Tomohiro, KURODA Akiko, YOSHIMURA Akinori, OGASAWARA Toshio, AOKI Takahira

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN Vol. 8 ( 27 ) page： Pc_5-Pc_9 2010

Coupled Thermal-Electrical Analysis for Carbon Fiber Composites Exposed to Simulated Lightning Current Reviewed

OGASAWARA Toshio, HIRANO Yoshiyasu, YOSHIMURA Akinori

JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES Vol. 57 ( 667 ) page： 336-343 2009.8

Language：Japanese Publishing type：Research paper (scientific journal)

This paper presents coupled thermal-electrical analysis of transient temperature distribution in carbon fibre composites (CFRP) exposed to simulated lightning current to understand the damage behaviour due to lightening strike. Thermal and electrical properties of CFRP were evaluated for each direction of the unidirectional composites. The thermal decomposition behaviour was also estimated from thermo-gravimetric analysis results. Based on the experimental results and preliminary analysis results, the electrical and thermal boundary conditions were discussed in detail. The numerical results are directly compared with the experimental results, and the damage mechanisms of CFRP exposed to impulse current were considered. As a result, it was inferred that the delamination of CFRP was mainly caused by the decomposition of matrix resin, and the fibres were broken by the sublimation due to high Joule heat generation.

DOI： 10.2322/jjsass.57.336

Damage Growth Analysis in Particle Reinforced Composites by Using Cohesive Elements Reviewed

YOSHIMURA Akinori, OKABE Tomonaga

Journal of the Japan Society for Composite Materials Vol. 35 ( 3 ) page： 112-120 2009.5

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

The present paper proposes a simple numerical analytical method for crack extension simulation in the particle reinforced composite, and reveals the effect of crack extension on the macroscopic material properties of the particle reinforced composite. This numerical method is based on the homogenization method and Dugdale-type cohesive elements. In the present paper, we first present the formulation of the numerical model. We then verify the validity of the numerical model by comparing the simulated crack extension with the linear fracture mechanics. Finally we perform the crack extension simulation for the composite reinforced by spherical particle. We consider the inclusion crack and interfacial crack between inclusion and matrix. The analytical results reveal that the inclusion crack extends always unstably regardless of the size of initial crack, and the evolution of inclusion crack sharply decreases the apparent Young's modulus in the perpendicular direction to the crack surface and shear modulus in the out-of-plane direction of crack surface. The results also demonstrated that the interfacial crack always extends stably regardless of the size of initial crack, and the evolution of interfacial crack gradually degrades the stiffness in all direction.

DOI： 10.6089/jscm.35.112

Improvement of out-of-plane impact damage resistance of CFRP due to through-the-thickness stitching Reviewed

A. Yoshimura, T. Nakao, S. Yashiro, N. Takeda

Advanced Composite Materials Vol. 18 ( 2 ) page： 121-134 2009.5

Permeation-after-impact Properties of CFRP Laminates for Use on Propellant Tank Reviewed

YOKOZEKI Tomohiro, KURODA Akiko, YOSHIMURA Akinori, OGASAWARA Toshio, AOKI Takahira

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, SPACE TECHNOLOGY JAPAN Vol. 7 ( 26 ) page： Pc_19-Pc_23 2009

板厚方向の縫合によるCFRP積層板の面外衝撃損傷抑制効果 Reviewed

吉村彰記, 仲尾知晃, 武田展雄

日本複合材料学会誌 Vol. 34 ( 5 ) page： 182-188 2008.9

円孔を有する縫合CFRP 積層板の損傷進展 Reviewed

吉村彰記, 矢代茂樹, 武田展雄

日本複合材料学会誌 Vol. 34 ( 1 ) page： 14-20 2008.1

Improvement on out-of-plane impact resistance of CFRP laminates due to through-the-thickness stitching Reviewed

Composites Part A: Applied Science and Manufacturing Vol. 39 page： 1370-1379 2008

薄層化によるCFRP積層板の耐漏洩特性の向上 Reviewed

横関智弘, 高木智宏, 吉村彰記, 小笠原俊夫, 荻原慎二

日本航空宇宙学会論文集 Vol. 56 ( 657 ) page： 492-497 2008

Characterization of tensile damage progress in stitched CFRP laminates Reviewed

A. Yoshimura, S. Yashiro, T. Okabe, N. Takeda

Advanced Composite Materials Vol. 16 ( 3 ) page： 223-244 2007

縫合CFRP 積層材の引張負荷下における損傷進展挙動 Reviewed

吉村彰記, 矢代茂樹, 岡部朋永, 武田展雄

日本複合材料学会誌 Vol. 32 ( 5 ) page： 198-207 2007

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Papers - YOSHIMURA Akinori