Papers - Takano, Naoki

Macro-micro uncoupled analysis procedure for nonlinear structural mechanics of composites - RVE approach to microstructural geometrically nonlinear problem

Takano N., Zako M., Ohnishi Y.

Zairyo/Journal of the Society of Materials Science, Japan (Zairyo/Journal of the Society of Materials Science, Japan)  45 ( 2 ) 163 - 168 1996.02

ISSN  05145163

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The purpose of this study is to develop a practical analysis procedure for nonlinear structural mechanics of composites. Especially, to solve such a nonlinear mechanical problem arising from the microstructural nonlinear behavior, the new homogenization procedure named macro-micro uncoupled method is proposed. First, the homogenized macroscopic material properties are calculated by precise microscopic nonlinear analysis. Then, macroscopic analysis can be performed easily by only referring to the pre-calculated nonlinear material properties. In this paper, RVE approach is taken for the microscopic nonlinear analysis, and the proposed macro-micro uncoupled method is applied to a microstructural large deformation problem of porous media.

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繊維強化複合材料の剛性設計のためのGAの効率的適用

TAKANO Naoki

材料 45 ( 12 ) 1316-1321 1996

Research paper (scientific journal), Joint Work, Accepted

複合材料の非線形構造力学解析のためのマクロ－マイクロ非連成化手法 －マイクロ構造における幾何学的非線形問題へのRVEアプローチ－

TAKANO Naoki

材料 45 ( 2 ) 163-168 1996

Research paper (scientific journal), Joint Work, Accepted

複合材料のマイクロ構造における幾何学的非線形性と破壊を考慮した均質化解析手法

TAKANO Naoki

日本機械学会論文集A編 62 ( 595 ) 859-864 1996

Research paper (scientific journal), Joint Work, Accepted

均質化法による織物複合材料の三次元マイクロ構造設計（第２報，曲げ負荷時のマイクロスコピックな挙動の詳細解析

TAKANO Naoki

日本機械学会論文集A編 62 ( 595 ) 884-889 1996

Research paper (scientific journal), Joint Work, Accepted

Macro-Micro Uncoupled Homogenization Procedure for Microscopic Nonlinear Behavior Analysis of Composites

Naoki Takano, Masaru Zako and Yoshihiro Ohnishi

Materials Science Research International (Materials Science Research International)  2 ( 2 ) 81-86 - 86 1996

Research paper (conference, symposium, etc.), Joint Work, Accepted,  ISSN  13411683

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For easy and practical simulation of microscopic nonlinear mechanical behavior of composite materials, new homogenization analysis procedure named macro-micro uncoupled method is proposed. In this procedure, microscopic simulation of material strength test is carried out first, then nonlinear homogenized material properties are obtained. Both the homogenization method and RVE (Representative Volume Element) approach are shown for this microscopic simulation. Macroscopic nonlinear behavior of a structure made of composite materials can be analyzed by only referring the pre-calculated homogenized material nonlinearity. As an example, microscopic fracture propagation for textile composite materials and microscopic large deformation for porous elastic materials are analyzed.

Numerical Prediction of Strength of UD Notched Laminates by Analyzing the Propagation of Intra- and Inter-laminar Damage

Masaru Zako, Naoki Takano and Takuya Tsumura

Materials Science Research International 2 ( 2 ) 117-122 1996

Research paper (scientific journal), Joint Work, Accepted

ワインディング構造物の仮想試作システム構築（第１報，テープワインディングならびにその強度）

TAKANO Naoki

日本機械学会論文集A編 62 ( 598 ) 1450-1455 1996

Research paper (scientific journal), Joint Work, Accepted

複合材料用三次元構造解析支援システムの構築

TAKANO Naoki

日本機械学会論文集A編 62 ( 598 ) 1501-1505 1996

Research paper (scientific journal), Joint Work, Accepted

Three-dimensional microstructural design of woven fabric composite material by homogenization method

Takano N., Zako M.

American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP (American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP)  302   141 - 146 1995.12

ISSN  0277027X

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The strength of woven fabric composite materials depends on the microstructural geometry. However, the conventional methods for mechanical analysis, which have been widely used so far, are insufficient because they cannot take into account for the three-dimensional microstructure. In this study, three-dimensional homogenization method is shown to be effective for the evaluations of the material constants, microscopic stresses and the strength. It has been found that the transverse stresses in the direction of lamination play an important role for the fracture of both fiber bundle and resin. Also, the effect of the mismatched lay-up on the strength has been investigated. It has well been predicted that the mismatched lay-up causes the reduction of the strength and the difference of crack initiation in the resin. These simulations give us a new concept of the microstructural design of the composite materials.

微視破壊を考慮した均質化法による織物複合材料の非線形解析

TAKANO Naoki

材料 44 ( 505 ) 1231-1237 1995

Research paper (scientific journal), Joint Work, Accepted

Fixed Grid に基づく均質化法による複合材料のマイクロスコピック・シミュレーション技法の提案

TAKANO Naoki

日本機械学会論文集A編 61 ( 583 ) 589-594 1995

Research paper (scientific journal), Joint Work, Accepted

均質化法による織物複合材料の三次元マイクロ構造設計（第１報，強度に及ぼす織物積層方向位置ずれの影響）

TAKANO Naoki

日本機械学会論文集A編 61 ( 585 ) 1038-1043 1995

Research paper (scientific journal), Joint Work, Accepted

Stress Analysis of Sandwich Plate by the Homogenization Method

Naoki Takano, Masaru Zako and Noboru Kikuchi

Materials Science Research International (Journal of the Society of Materials Science, Japan)  1 ( 2 ) 82-88 - 88 1995

Research paper (scientific journal), Single Work, Accepted,  ISSN  05145163

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The effectiveness of the homogenization method for analysis of composite materials has been shown since it was firstly introduced in 1970's. As this method is applicable to periodic problems only, however, some engineering problems remain unsolved. For instance, we could not apply it to honey-comb sandwich plates and panels with reinforcing ribs because these structures are not periodic in the thickness direction. In this paper, the application of the homogenization method to those composite structures is discussed. As a practical example, stress analysis of single-layered corrugated core sandwich plate is presented. A method to homogenize the complicated geometry to a simple solid model, to get the homogenized material constants, and to calculate the microscopic stress is proposed. © 1995, The Society of Materials Science, Japan. All rights reserved.

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均質化法による単層波状コアサンドイッチ板の解析－面内のみ周期性を有する複合構造への均質化法の適用について－

TAKANO Naoki

材料 44 ( 502 ) 905-910 1995

Research paper (scientific journal), Joint Work, Accepted

損傷力学に基づく複合材料用三次元有限要素法の開発

TAKANO Naoki

材料 44 ( 502 ) 921-926 1995

Research paper (scientific journal), Joint Work, Accepted

信頼性に基づく先端材料用設計寿命評価システム

TAKANO Naoki

日本機械学会論文集A編 61 ( 589 ) 1909-1913 1995

Research paper (scientific journal), Joint Work, Accepted

Analysis of Single-Layered Corrugated Core Sandwich Plate by Homogenization Method — On the Application of Homogenization Method to Composite Structures with Only Planar Periodicity —

Takano N., Zako M.

Journal of the Society of Materials Science, Japan (Journal of the Society of Materials Science, Japan)  44 ( 502 ) 905 - 910 1995

ISSN  05145163

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The effectiveness of the homogenization method for the analysis of composite materials has been shown since it was firstly introduced in the 1970's. As this method is applicable to periodic problems only, however, some important engineering problems remain unsolved. Those problems are, for instance, honey-comb sandwich plates and panels with reinforcing ribs, which are not periodic in the thickness direction. In this paper, the application of the homogenization method to those problems is discussed. As a pratical example, stress analysis of single-layered corrugated core sandwich plates is presented. A method to homogenize its complicated geometry to a simple solid model, to get the homogenized material constants, and to calculate the microscopic stress is proposed. © 1995, The Society of Materials Science, Japan. All rights reserved.

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Development of Design Margin Decision System for Advanced Materials Based on Reliability

Zako M., Takano N., Ichikawa M., Hanaki S.

Transactions of the Japan Society of Mechanical Engineers Series A (Transactions of the Japan Society of Mechanical Engineers Series A)  61 ( 589 ) 1909 - 1913 1995

ISSN  03875008

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The design concept based on reliability is effective for advanced materials, because advanced materials such as fiber-reinforced composites have variable mechanical properties. In addition, as the failure mode in the low cycle fatigue region differs from that in the high cycle fatigue region, it is difficult to predict the fatigue life of advanced materials. So far, we have developed a design margin decision system based on reliability by evaluating fatigue life. In this study, the system is improved for application to advanced materials and a method to divide whole sets of data into the above two regions and to calculate the design margin in each region is presented. From numerical examples for CF/PEEK laminates and epoxy resin, it is revealed that a more reasonable S-N curve and design margin are obtained by the proposed system. © 1995, The Japan Society of Mechanical Engineers. All rights reserved.

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Three Dimensional Microstructural Design of Woven Fabric Composite Materials by the Homogenization Method (1st Report, Effect of Mismatched LayUp of Woven Fabrics on the Strength)

Takano N., Zako M., Sakata S.

Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A (Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A)  61 ( 585 ) 1038 - 1043 1995

ISSN  03875008

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The strength of woven fabric composite materials depends on their microstructural geometry. However, the conventional methods for mechanical analysis, which have been widely used to date, are insufficient because they cannot take into account the three-dimensional microstructure. In this study, the three-dimensional homogenization method is shown to be effective for determination of the material constants, microscopic stresses and strength. It has been found that the transverse stress in the lamination direction plays an important role in the fracture of both the fiber bundle and the resin. Also, the effect of the mismatched lay-up on the strength has been investigated. It was predicted that the mismatched lay-up causes a reduction in strength and a difference of crack initiation in the resin. These simulations provide a new concept for the microstructural design of composite materials. © 1995, The Japan Society of Mechanical Engineers. All rights reserved.

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