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4 Recommendations Based upon its findings the committee offers the following recommendations noting that the tough budget decisions made a few years ago have created a program malaise and have seriously degraded the leadership role of NASA in the impor- tant technology of advanced organic composites for aircraft structures. Momentum generated by past NASA programs, such as those directed at medium primary struc- tures, is rapidly dissipating. The committee believes it is timely and appropriate to begin a BOLD NEW PROGRAM (BNP) characterized by the following THRUSTS, which are discussed in more detail in Sections I and II of the report Supplement. The reader is encouraged to examine the Supplement.* THRUSTS 1. NEW STRUCTURAL CONCEPTS: The BNP should foster full recogni- tion that the basic components of advanced organic composites are filaments and matrix, i.e., "strings" and "glue." A new way of thinking needs to be promulgated to overcome 40 years of devotion to design concepts that may be appropriate only for isotropic metallic materials. It has been said with much accuracy that many, if not most, of the present composite applications are "black aluminum"; the metal ma- terial in a metal design has merely been replaced with black filamentary composite material. More innovative design and manufacturing concepts that fully utilize the inherent characteristics of composites must be pursued. University programs could be helpful here. (Pages 23, 24, 26, 29) 2. MANUFACTURING: The BNP should encourage new manufacturing methods that will exploit the filament and matrix nature of composite materials *Some of the committee's views relevant to these THRUSTS and the following RECOMMEN- DATIONS are on the pages of the Supplement noted after each summary statement. 12
IS and reduce production costs. Structural concepts should be integrated with manu- facturing. There is a tremendous investment in metal shaping and fabricating tools, but progress in the application of advanced composites has been and will continue to be impeded if the tooling for metals continues to be used for filamentary com- posites. "Free" thinking, leading to new and improved concepts, will be discouraged if the designer thinks in such terms as five-axis milling machines, drill presses, and conventional tooling concepts. (Pages 25, 26, 29) 3. CRITICAL EXPERIMENTS: Experiments (of sufficient scale) are the linchpins to a better and sufficient understanding of the fundamental issues of frac- ture, longevity, damage tolerance, durability, and other issues of structural strength and integrity. Critical work should be identified and supported. (Pages 26, 29) 4. DESIGN METHODOLOG Y: The development of analytical methods that blend theory and empirical and experimental data, and permit extrapolation of data from the laboratory to full-scale design, is very important. Analytical methods for failure analyses are needed for designers to assess properly the structural margins of safety. It is important to recognize that large finite-element programs that make use of supercomputers will spew out reams of useless answers if the failure theories and analytical methods are in error. The design methodology is only as good as the experimental data base upon which it is structured and hence this analytical thrust must be closely coordinated with and depend on experiments for proof. (Pages 24, 25, 26, 29) 5. DATA BASES: The term "data bases" as used herein relates to material and structural matters required to reduce the risks of new composite structure de- signs to levels acceptable to designers and chief engineers. Data pertinent to such matters as material properties (ranging from tensile ultimate strength to behavior at moderate and high temperatures to moisture absorption), methods of testing, com- pressive behavior of laminates, and bonded-joint design have to be addressed. Well- organized and well-documented data bases should be published and disseminated to appropriate government, industry, and academic organizations. It is recognized that the development of material data bases will be a more difficult, drawn-out process than that for other technical matters due to the dynamics of material development. This difficult matter should be explored with industry to identify what should be pursued. (Pages 23, 26, 29, 36) 6. EDUCATION: Generations of young engineers are needed whose baseline knowledge is orthotropic rather than isotropic, heterogeneous rather than homoge- neous, and who deep down in their pysches regard metals as a special case of fila- mentary composites. The BNP should address resources to the engineering schools to help achieve these goals. (Pages 25, 26, 29) RECOMMENDATIONS Based on the preceding observations and committee deliberations, and Sections I and II of the report Supplement, the committee RECOMMENDS the following:
14 1. The government, through NASA, DOD, and FAA, should establish a BOLD NEW PROGRAM for advanced organic composites research and technology devel- opment (R&T). The committee believes an order-of-magnitude increase in funding is justifiable on the basis of the expected returns. (Pages 36, 37) 2. The objectives of the BOLD NEW PROGRAM should be to enlarge the technology data base and to enhance the opportunities for early application of the technology. (Pages 23, 29, 38) 3. The BOLD NEW PROGRAM should be innovative and visionary, and the R&T effort should provide the government and industry with the capability to capitalize on the potential of advanced organic composite materials. (Pages 23, 25, 40) 4. The BOLD NEW PROGRAM, in addition to basic R&T, should be directed at cost reduction from material to design through construction and testing; the pro- gram should expand the related data bases, include necessary large-scale technology validation activity, and appropriately support related academic activity. (Pages 23, 37) 5. NASA, DOD, and FAA should jointly define and implement the program with inputs from industry and the universities and consider joint ventures for large- scale expensive projects. (Pages 25, 26, 29, 31, 34, 36, 37, 41)
