Composite materials out of reinforcements such as glass fiber, boron fiber, carbon fiber, etc. and resin matrices have been developed in the time of the World War II and the Cold War. The composite materials have found widespread application and recognition as the new materials addition to the existing stones, metals and wood. In this review, the brief history of the composite materials and issue to be studied in the near future are presented.

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Decorative Composites are the composite materials having artistic characteristics in addition to functional characteristics. As FRP has good dyeing and weaving property, FRP is the material which easily can add artistic characteristics. It is high possible that the decorative composites product a new field on the fibrous composite industry in 21 century. The relationship between fibrous products and Kansei engineering is described, and then the decorative composites are introduced in this paper.

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Functional materials have been the promoting powers of new material developments And the changing the compact products are depending on the functional characteristics of materials. In these situation, composite materials have been putting to practical use for the high-ability and high-functional materials too. But recently changing the way of thinking for the development of high-functional materials, there are many problems which are resources of effectively use and environmental problem for related to materials and so on. Therefore, there are many trials for using of the biomaterial’s function. Here, standing on these situation,structure and function of biomaterials are discussed about related materials to make artificially and examine of the composite materials to develop for the high-functional and high-ability of these materials.

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This paper describes recent studies on smart composites running in Japan. Many researches and developments on smart composites can be seen at Japanese conferences on composite materials. These studies can be categorized into sensing and actuating from the viewpoint of the smart functions. The sensing functions are applied to process monitoring and health monitoring. On the other hand, the actuation functions are available for vibration damping, noise reduction, high-deformable composites and repair. All of these applications of smart composites are studied in Japan. The functional elements mentioned in this paper are optical fiber sensors, dielectric sensors, piezoelectric materials, shape memory alloy (SMA) and electro-rheological (ER) fluid. Polymer matrix composites (PMC) are mainly used as host composite materials, while the smart composites using metal matrix composites (MMC) are also proposed. Researchers in Japanese institutes have focused on the basic researches of smart composites since the early 1990 s. In addition, practical studies in Japan have been increasing because it has been recognized that smart composites is a promising technology to reduce the cost, improve the reliability and upgrade the value for a few years. As well as the basic studies in laboratory, the practical studies are addressed here.

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Recent artifacts have gained a high degree of intelligent or smart characteristics, and it is important to investigate the general feature of such intelligence or smartness. First, a definition and classification of artifacts are discussed, and a definition of intelligent artifacts is proposed. In addition to the function and the performance of artifacts, an intelligent attribute is introduced as the third coordinate axis. It is shown that the intelligence of artifacts corresponds to the automatization of the application, operation, and management of artifacts. The necessity of intelligent artifacts and the purpose of the intelligence are examined. It is revealed that the intelligent characteristics aim for adjusting the parameters of artifacts to provide the optimum performance against their environmental changes and reducing the load of users and natural and social environment. The purpose of intelligent characteristics is to increase the advantages provided by the artifacts and to decrease their disadvantages by changing their parameters after sensing their environmental change.

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Generalized optimization in engineering design is a synthesized problem. In this paper, some approach of authorized optimization in engineering design was reviewed. In chapter 2, some outlines in optimization were introduced. In chapter 3, an integrated system of design and production for metal sheet forming in virtual manufacturing was introduced as a case study of integrated optimization problem. In the system, the designer is able to evaluate the design process by a parameterized evaluation function and to examine the production results based on these design strategies in virtual space by means of CAD/CAE. In the paper, it is pointed out that the gap between simulation and experiments or real production must be taken into account whenever these kinds of product innovation enable us to obtain a quick response and result for the candidate design strategies in computer simulation. In chapter 4, some method of Quality Engineering was introduced.

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The essential difficulties to evaluate the mechanical properties of composite material structures lies in the fact that various kinds of mechanical, geometrical and material inhomogeneity should be taken into consideration in every phase of analysis, ranging from fiber/matrix interfaces to adhesive joints of structural components. Damage growth process of composite materials is very complicated and modeling has not been easy. However the recent advances in experimental and computational mechanics have been making it possible to offer more flexible and versatile techniques, ranging from micro(or meso)-mechanics to macro-mechanics, for more realistic and accurate modeling of composite material structures, not only for structural performance but also for damage growth process. This paper illustrates and discusses several typical and successful applications of these approaches to modeling of mechanical properties of composite material structures with special reference to characterization of damage and damage progression.

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A prediction method of fatigue strength of polymer composites for an arbitrary frequency, stress ratio, and temperature is proposed. The method is based upon the four hypotheses, (A) failure mechanism for CSR (constant strain-rate), creep, and fatigue failure is the same, (B) the same time-temperature superposition principle holds for all failure strengths, (C) linear cumulative damage law is applicable for specimen failure under nondecreasing stress process, and (D) fatigue strength shows linear dependence upon stress ratio. Satin woven CFRP laminate was chosen as an example of application of the prediction method. The validity of hypotheses B, C, D, and the applicability of this prediction method were experimentally confirmed. It was also confirmed that the hypothesis A is not necessarily always for this prediction method through discussions. Furthermore, the range of combination of fiber and matrix resin to which the prediction method is applicable was shown. Finally, the future issues which should be solved for the practical use to the durability design are listed.

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Foamed plastics are a kind of composite materials consisted in air and resin. They have unique characteristics for heat transmission and electric conduction, impingement protection with materials reductions, light-weight, low-density and so on. Many foam processing technologies have already been developed using chemical and physical blowing agents and put into practical use. But these conventional foamed plastics have a serious problem, which the strength decreases extremely owing to voids as a defect. In order to correct this defect, a new processing technology using supercritical fluid/gas as a blowing agent for foamed plastics, which is called to microcellular plastics, was developed in US. This process technology has also advantages over much conventional foam processing because it uses environmentally sound gases such as carbon dioxide and nitrogen as blowing agents, rather than toxic chemical blowing agents. In this paper, the present situation of process technology of microcellular plastics is introduced.

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Failure criteria are sets of mathematical rules used to predict the failure of a material under complex stressstates. Composite laminates fail progressively ply by ply, and progressive failure criteria are used to predict this behavior. Four major failure criteria, Maximum Stress, Tsai-Wu, Hashin, and Christensen failure criteria were compared in this study. By combining these failure criteria with simple progressive damage scheme, progressive failure criteria of composite laminates were formulated and evaluated. Good agreements between the predictions and the test measurements were observed. The predicted final failure loads were observed to be insensitive to the choice of the failure criteria, although the predicted initial failure loads are different. We believe that the simple progressive damage calculation shown in this paper is useful for the designers and engineers, and are ready to provide an easy-to-use Excel-based code for our progressive quadratic failure criterion.

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Pulsed YAG laser beam system is applied to surface hardening process of three kinds of Cr-Mo steel with different carbon content, and structural property of hardened and intermediate zone is investigated in relation to carbon content and laser irradiation condition. Hardness of hardened zone of each steel is found to depend on carbon content as the similar manner as ordinal quenched steel cooled by water or oil, and the hardness is more constant than normal carbon steels because of contained chrome and molybdenum. The intermediate zone of proeutectoid ferrite and martensite in the vicinity of the boundary of hardened zone and virgin structure is produced from 0.22% C-Cr-Mo steel with hypo-eutectoid structure, which is observed clearly by hardness tests. Hardness dose not change in hardened zone, and the intermediate zone consisting of rich martensite structure is produced from 0.41% C-Cr-Mo steel with hypo-eutectoid structure. The intermediate zone is not produced from 0.65% C-Cr-Mo steel with eutectoid structure due to chrome contained. The dimension of the laser irradiated and hardened zones can be adjusted by selecting the laser irradiation condition, with some technical treatment depending on steel ; such as hypo-eutectoid or eutectoid steel.

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In this paper is examined a simple identification method of force locations and histories of point impacts on anisotropic composite laminated plates by using measured values of acceleration, in which the force locations are identified through an iteration procedure. The data processing method for improving the accuracy of identification is also examined when the measured values of acceleration contain measurement errors. To verify the validity of the identification method, the identification is performed for balanced laminated plates and cross-ply laminated plates using the measured values of acceleration without measurement errors. The identification results are compared with the exact ones and it is found that the acceptable identification results are obtained for not so much great number of measurement points. Finally, using the measured values of acceleration with measurement errors, the accuracy of identification by three different data processing is examined for balanced laminated plates. As the　result, the best accuracy of the identification results is achieved for the data processing of running average.

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First, tensile test were conducted on two types of CFRP cross-ply laminates to clarify the effect of laminate configuration on the microscopic damage behavior quantitatively. Second, tensile loading-unloading tests and shear tests were conducted on laminates containing microscopic damages to clarify the reduction of elastic properties. Several analytical predictions were compared with experimental results to evaluate the effectiveness of those analyses.

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In this study, evaluation of hygrothermal environmental effects on the graphite/epoxy laminate was demonstrated. In the theoretical part, the Rayleigh-Ritz method was extended to predict the shape of unsymmetric laminates [0/0/90/90] in moist environments. In the experimental part, the curvature changes and the weight changes of the unsymmetric laminate were measured continuously during moisture absorption. The comparison between experimental results and numerical simulated results was effective to understand the behavior of the laminate in the hygrothermal environments. It was found that there are discrepancies between experimental results and numerical results at the high moisture contents, specifically at the high water bath temperature during water absorption. The chemical reaction due to water influences in the laminates, and the limitation of the simulated modeling may result these discrepancies, however, further investigation will be required.

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GFRP has been used as anti-corrosive material, but severe accidents were reported occasionally. Acid stress corrosion is the one of famous problem for such an application, and has been well studied. The examples of the accident related to corrosion of GFRP were shown and the cause of these accidents was investigated in this study. A GFRP vessel containing 75% H2SO4 and broken only for 1 year was investigated chemically and microscopically. Many cracks were found at inner surface of the vessel and the solution would have been leaked out through these cracks. From FT-IR analysis, it was confirmed that the matrix resin even at inner side was not affected by the solution. From microscopic observation, it seemed that the matrix/reinforcement interface would be debonded and the stress could not be transferred between matrix resin and reinforcement. This debonding was considered as the starting point of cracks. To understand the cause of this kind of accident, the specimen with the similar defects as the actual vessel was recreated. In consequence, it was found the cracks occurred in shot period. Furthermore, it was suggested that the curing condition seriously caused the accident.

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