NASA/Langley Research Center, Mail Stop 144, Industry Assistance Office, Hampton, VA 23681-0001

A -- OPTIMIZATION TO INVESTIGATE METHODS FOR REDUCING MATRIX CRACKING IN POLYMER MATRIX COMPOSITE(PMC) MATERIALS WHEN SUBJECT TO EXTREME TEMP CONDITIONS AS IN CRYOGENIC TANKS OF REUSABLE LAUNCH VEHICLES SOL 1-168-RCE.1114 DUE 071400 POC Kimberly D. Duncan, Contract Specialist, Phone (757) 864-3566, Fax (757) 864-6966, Email k.d.duncan@larc.nasa.gov -- Susan E. McClain, Contracting Officer, Phone (757) 864-8687, Fax (757) 864-8863, Email s.e.mcclain@larc.nasa.gov WEB: Click here for the latest information about this notice, http://nais.msfc.nasa.gov/cgi-bin/EPS/bizops.cgi?gr=D&pin=23#1-168-RCE .1114. E-MAIL: Kimberly D. Duncan, k.d.duncan@larc.nasa.gov. NASA/LaRC plans to issue a Request for Quotation (RFQ) for Research and Development for Optimization expertise to investigate methods for reducing matrix cracking in polymer matrix composite (PMC) materials when subject to extreme temperature conditions as in cryogenic tanks of Reusable Launch Vehicles (RLVs). Base Requirement: Award through September 29, 2000. Option 1: September 30, 2000 -- March 2, 2001. The Base requirement will require: 1) Trade studies for PMC cryogenic tanks shall be performed to assess the effect of various methods available to minimize microcracking on the optimized weight of the tank. Mechanisms at laminate level and structural level that can minimize matrix stresses will be investigated. 2) The effect of temperature dependent material properties on thermal residual stresses will be investigated. Various failure models for matrix crack initiation such as maximum stress, strain and fracture mechanics models based on shear lag theories. The results will be compared to temperature dependent 3-dimensional nonlinear analyses. 3) A 3-dimensional nonlinear static/bifurcation code shall be used to perform verification and validation of structural design concepts that will minimize stresses and reduce microcracking of laminates. 4) Sensitivity analysis shall be performed to identify relative importance of design parameters, use the developed information for probabilistic design, and thermal residual stress analysis shall be performed on all composite concepts. Option I: 1) In addition to using temperature dependant properties for reduction of thermal stresses, laminates will be designed with partial failure of the plies (in matrix failure), and the use of compliant ply layers for laminate design will be considered. A two-material-system genetic algorithm (GA) shall be developed and used to design laminates with intervening compliant layers and also for laminate design with partial microcracking. 2) Analysis techniques for compliant layers in PMS shall be developed. Three-dimensional Finite Element Models (FEM) with appropriate constitutive laws for the various materials shall be used. 3) Imperfection sensitivity analysis shall be performed, and thermal residual stress analysis shall be performed on all composite concepts. 4) Closed form solutions shall be developed for a more efficient mechanics model to replace the 3-dimensional FEM. The closed form solutions shall be compared to the generated 3-dimensional FEM model's results. This procurement is being conducted under the Simplified Acquisition Procedures (SAP). NASA/LaRC intends to purchase the items from University of Florida, Dr. Rafael T. Hafka, Dept. of Aerospace Engineering and his post doctoral students, who has unique knowledge available from only one source. Dr. Hafka has performed on previous grants and purchase orders that has given him unique capabilities to perform on this task. There would be substantial duplication of cost for another person to obtain the required knowledge to support this requirement and such costs are not expected to be recovered through competition. The Government does not intend to acquire a commercial item using FAR Part 12. See Note 26. Interested organizations may submit their capabilities and qualifications to perform the effort in writing to the identified point of contact not later than 4:30 p.m. local time on July 14, 2000. Such capabilities/qualifications will be evaluated solely for the purpose of determining whether or not to conduct this procurement on a competitive basis. A determination by the Government not to compete this proposed effort on a full and open competition basis, based upon responses to this notice is solely within the discretion of the government. Oral communications are not acceptable in response to this notice. All responsible sources may submit an offer which shall be considered by the agency. An Ombudsman has been appointed. See NASA Specific Note "B". Any referenced notes can be viewed at the following URL: http://genesis.gsfc.nasa.gov/nasanote.html Posted 06/30/00 (D-SN470736). (0182)

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