Composite Materials were expected to realize materials revolution and bring great benefite for human life with light weight and long life machines. But people seems to be tired of developing new materials because of severe decay of economy, and just waiting watchfully. To make sure of this trend, the research state of composite materials in Japan was briefly reviwed, and made an anticipation on the future of composite materials such as intelligent materials and intermetallic compounds.

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Japanese Composites Materials Industry proudly displaying as the Number 2 Country of production in the World has reached to rate of around 700,000 tons per year after carried out the efforts in the period of four dacads since commenceing the industriazation it's self. However, the Industry is facing a sever situation recently. This is just the moment of revolution for this Industry which is in the turning point whether it will be able to keep it's potentialty as the progressive one. This report is looked back on the past transitions of the Composite Industry, and described the development on the technologies in the raw materials, molding methods and the markets. Then a serch was done on the recent trends of those technologies and markets in Japan. Also some expectation was pointed out on the capability of the Industry in the next dacade with summarized opinions by the pioneers of each generation. The Field of Composite Materials is yet in the States of Arts. We are convinced that it is the most attractive affair for the Enterprisers and Engieneers from now on. “The Way to a Brilliabnt Future for The Composite Mterials” should be reflected by the wills and efforts of the Leaders who will have a Pulling Power for this Industry.

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This paper describes various concepts and ideas so far proposed on how to reconsider the design of composite materials and structures for the purpose of aiming at smart composite structures. The target of developing smart composite structures is first overviewed and the importance of some intermediate and near term targets is pointed out in making a breakthrough in the present composite technology. Such examples are a health monitoring for more efficient inspection and maintenance of composite structures and also adding a new function of recyclability which is most lacking in the existing composite structures. As composite materials are essentially inseparably related to product design, the future role of composite materials should be discussed in terms of more general trends of redefining manufacturing industry in view of paradigm shift, life cycle assessment, inverse manufacturing and so on. Then the possibility of polyfunctinal composite materials is discussed from the viewpoint of ecobalance and environmental harmonization by introducing several prototype concepts.

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Composites materials have been used for many industrial fields. So that many raw materials of reinforcement materials have been needed the high strength and high elastic modulus and matrix materials have been required the excellent moldability and high heat resistance properties. In this paper, the design of materials and molding technology of composite materials are discussed by thinking of the biomaterials and biological technology. In order to use raw materials efficiently, synsetic, metal and ceramics materials etc., we have to develop the basic tehnology of composites to promote making the new material and products. So the important basic items to promote the composite technology for those matters are as follows. 1）Development of the new raw materials which are renforcement and matrix materials. 2）Establishment of material design to be required the mechanical and functional properties. 3）Development of the moding and joning tehnology in composite materials. So the design of materials and molding technology for making new composites and products were examined and discussed with the future developments.

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This paper deals with the transition of Polymer Matrix Composites (PMC)- from Hard Composites to Soft Composites. The five kinds of typical stress-strain relations in PMC are shown at first. PMC is explained by dividing between the hard composites and the soft composites. The hard composite is difined as the composite with high strength and high rigidity. On the other hand, the soft composite is defined as the composite which have the high tensile strength and high tensile rigidity, but low flexible and compressive rigidities. The hard composites have about 60 years' history which consists of three generations, and the soft composites about 50 years' history. This paper storongly mentioned that the soft composites have the wide application field as same as the hard composites.

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Composite materials have potential of designing their mechanical properties. However, this advantage is not fully utilized in the design and application of present composite materials. One of the reason for this situation is that the relation between microscopic properties of components such as fiber and matrix, and the macroscopic composite strength is understood only at a qualitative level. During deformation and fracture behavior of fiber reinforced composites, various events such as premature failure of fibers, interfacial debonding, fiber bridging, matrix fracture etc. occur. Interfacial strength and the geometrical arrangement of fibers and matrix affect these events. These events and structures are called mesoscopic events and mesoscopic structure. The mechanics which describes the mesoscopic events, the effect of mesoscopic structure, and total contribution of a number of mesoscopic events to the overall behavior of macroscopic composites is called mesomechanics. Mesomechanics has further potential to increase the mechanical properties of composites by controlling the mesoscopic structures. In the present paper, the importance of the contribution of mesoscopic structure on the overall composite behavior is addressed, and then the possibility of mesomechanics is described.

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Some recent studies on experimental micromechanics of composites by the authors were summarized. One is an in-situ scanning acoustic microscopy using a high number-of-aperture lens to detect the initiation and growth of transverse cracks and delamination in CFRP cross-ply laminates. Novel micromechanical damage evolution models were established to explain the experimental results. The other is an in-situ scanning electron microscopy using micro-lines or grids printed on the laminate specimen edge to visualize microscopic deformation and damage near the transverse crack tip. Temperature dependence of the interlaminar shear deformation and the axial crack opening displacement was obtained, and also predicted successively by a micromechanical model considering thermal residual stresses. Such experimental micromechanical approaches provide a reasonable basis for establishing the damage tolerance design of composites.

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Future of composite materials is discussed from a new viewpoint of property conversion. Author pointed out “rule of mixture” is not a principle for development of composite materials, but property conversion is the key engineering for creation of composite materials. Property conversions are often found in mechanics of composite materials. New composite material can be successfully developed by discovery or by invention of property conversions.

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When polymeric smart structures were to be developed, the main matrix material would become fiber reinforced thermoplastics (FRTP), which were required to have several preferable aspects such as advantageous processing, ability of adding multi-function features and easy recycling in comparison to other materials. In particular, environmental compatibility is of most common and urgent subject all over the world in order to prevent ecological environment from getting it worse than ever. In this connection, the development of recycling technology must be taken into account in the first place, while smart structural material is being pursued to be developed. This paper deals with the concept of smart composite structures which has environmentally friendly features represented by ecological process system including possibility of new technology on the development of purpose-oriented and selfresolvable intelligent materials and structures.

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PAN based carbon fiber (PAN-CF) consumption has been remarkably expanded for a recent few years. PAN-CF production trials started in 1960's and now more than 70% of its production roughly estimated as 10,000 tons per year to be consumed is made by Japanese PAN-CF makers and their subsidiary companies. The usage of PAN-CF is diversified from aircraft and aerospace field and sporting goods field to industrial field like civil engineering, energy stocks and wind generation. Such diversification of applications leads critical PAN-CF shortage. For solving such shortage, PAN-CF producers have plans to expand their production capacity, which will be completed PAN-CF by end of 1998.

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Pitch-based carbon fibers have been developed for over 20 years and provide wide range of stiffness, high thermal conductivity, low coefficient of thermal expansion and other unique properties. The history of pitch-based carbon fiber, mechanical properties, physical properties and various applications for pitch-based carbon fiber reinforced plastics are reviewed to study the future trend for pitch-based carbon fiber and its applications.

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The various composite materials are used in electrical machineries for insulation and structure. These composites are required various characteristics simultaneously, for example electrical insulation, heat resistance, radiant ray resistance. But these requirement can not satisfy with a simple substance. Then, the insulating materials are typically composed with resin, reinforcements which are glass fibers, and mica. The future trend of composites for electrical machineries is considered as the following items, materials system design linked to process, inspection and estimation of reliability under combined degrading factors.

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The concept of “Materials System” proposed when Materials System Research Laboratory was established seventeen years ago in Kanazawa Institute of Technology is introduced again and the new concept of “Total Man Materials System” is proposed based on the limitation of natural resources. The signification of the life prediction of composite materials already proposed by the authors and others is discussed on the viewpoint of Total Man Materials System.

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A hydrogen permeation test in dual phase metals composed by α and γ phases was simulated for some models using Crank-Nicolson method. Diffusion constants of hydrogen in α and γ phase were assumed to be 1.5×10^-11 and 3.8×10^-15 m²s^-1 respectively ; the ratio of hydrogen solubility of γ to α phase was assumed to be 8.8. According to the result of numerical simulation, hydrogen diffuses at first in the α phase, of which diffusion constant is large, around γ phase, of which diffusion constant is much small, the starts diffusing into the γ phase from every direction. Thus, γ phase delays hydrogen permeation and decreases amount of hydrogen permeation. This effect becomes large with aspect ratio of γ phase.

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The paper presents an effective optimization approach on laminate configurations of symmetrically laminated plates for various kind of stiffness characteristics, i.e., bending, vibration, buckling and panel flutter. The coupling between bending and twisting is taken into consideration in the stiffness analysis of symmetrically laminated plates. Using lamination parameters, the effect of bending-twisting coupling on stiffness characteristics is discussed for the case of simply supported edges. The relation of laminate configurations and stiffness characteristics is also clarified based on a concept of lamination parameters. Optimal laminate configuration for various kind of stiffness characteristics is obtained using a mathematical programming method where four lamination parameters are used as design variables. The optimal lamination parameters and the corresponding laminate configuration can be obtained easily by the present approach.

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Tensile tests of interlaminar-toughened CFRP cross-ply laminates are carried out in a SEM (scanning electron microscope). Microscopic deformation in interlaminar region around the transverse crack tip and crack opening displacement of transverse crack are measured by micro-lines which are printed on the specimen surface by using the photolithography technique. Tests are performed at room temperature and 100℃ to evaluate temperature effects on shear deformation in interlaminar layers and crack opening displacement. The experimental results are compared with the mathematical model based on the principle of minimum potential energy. In the present study, the analysis is modified to consider the interlaminar layers.

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Strains in unidirectionally carbon fiber aligned plastic composites under tensile loading were measured by optical interferometry. The single-mode optical fiber was attached to the test specimen using gauge cement. Two types of optical interferometer, Michelson and Mach-Zehnder types, were employed. The gauge length of optical fiber sensor was controlled with Teflon sheet. Strains measured with optical interferometers showed a good agreement with those measured with the iron strain gauge. The optical fiber sensor permits the strain measurement with a range of over 1.5%.

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Scattered light photoelastic image involves inevitably dispersed noise with high brightness over the whole field. This type of noise plays detrimental role for the precise and accurate analysis of three dimensional stress state. The authors discuss an effective image processing method not only for the noise reduction but for reconstruction of scattered light photoelastic image, using two images obtained from different polarization angles. A typical example of scattered light photoelastic image of a circular disk frozen under diametrical compression was successfully reconstructed.

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Deformation and sealing properties of rubber gasket of dresser type expansion coupling were analyzed by the axisymmetric finite element method (FEM) which dealt with nonlinear elastic and contact deformable-to-deformable problem. Axial tension stress of the bolt and strain on the middle ring of coupling were also measured by using strain gage method. The FEM model is applicable, since the tendency of calculated results by FEM are similar to the those of experiments. The gasket is forced out the airtight area, and the strain energy of gasket becomes higher on the contacting surface with the pipe and middle ring. The seating stresses of gasket on the pipe and the middle ring increase near the front edge of gasket. The tendency of seating stress distributions are change little, if the coupling is given the internal pressure or the expansion of pipe.

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