A foldable expandable pallet having a basic square configuration is disclosed. Each pallet is comprised of a plurality of struts, joined together by node point fittings to make a rigid structure. Some of the struts have hinge fittings and are spring loaded to permit collapse of the module for stowage and transport to a space station. Dimensions of the pallet are selected to provide convenient, closely spaced attachment points between the relatively widely spaced trusses of a space station platform. A pallet is attached to a truss at four points; one close fitting hole; two oversize holes; and a slot; to allow for thermal expansion/contraction and for manufacturing tolerances. Applications of the pallet include its use in rotary or angular joints; servicing of splints; with gridded plates; as an instrument mounting bases; and as a roadbed for a Mobile Service Center (MSC). Official Gazette of the U.S. Patent and Trademark Office National Aeronautics and Space Administration. Marshall Space Flight Center, Huntsville, AL. SPACECRAFT COMPONENT HEATER CONTROL SYSTEM Patent Application Frederick D. Bachtel, inventor (to NASA) and James W. Owen, inventor (to NASA) 5 Jun. 1989 16 p (NASA-Case-MFS-28327-1; NAS 1.71:MFS-28327-1; CSCL 22B A heater control circuit is disclosed as being constructed in a single integrated circuit, with the integrated circuit conveniently mounted proximate to a temperature control. Redundant heater controllers control power spacecraft component requiring applied to strip heaters disposed to provide heat to a component responsive to sensed temperature from temperature sensors. Signals from these sensors are digitized and compared with a dead band temperature and set point temperature stored in memory to generate an error signal if the sensed temperature is outside the parameter stored in the memory. This error signal is utilized by a microprocessor to selectively instruct the heater controllers to apply power to the strip heaters. If necessary, the spacecraft central processor may access or interrogate the microprocessor in order to alter the set point temperature and dead band temperature range to obtain operational data relating to the operation of an integrated circuit for relaying to the ground control, or to switch off faulty components. NASA N89-28558# Naval Postgraduate School, Monterey, CA. Large space structures are difficult to control because of the high order of their mathematical models. The high order mathematical model makes the use of a reduced order model to control the structure desirable. The Karhunen-Loeve expansion along with Galerkin's method is used to generate a reduced order model. A control algorithm is achieved by applying linear quadratic regulator theory to the reduced order model. The Karhunen-Loeve basis functions or mode shapes must first be found to identify the reduced order model. Previous results have shown that in the limit as the structural damping approaches zero the KarhunenLoeve mode shapes and natural mode shapes converge. Numerical techniques are applied to evaluate the structural damping required for convergence. Once the Karhunen-Loeve mode shapes are determined, the reduced order control model is applied to the full order system. The performance of various Karhunen-Loeve models is compared by measuring the modal energies in the controlled and uncontrolled modes. GRA N89-28560# Naples Univ. (Italy). Istituto di Aerodinamica. Raffaele Savino 1988 161 p In ITALIAN The hypersonic reentry problem is analyzed in relation to the Hermes vehicle design. The equilibrium properties of the high atmosphere and the molecular energy distribution are discussed. A mathematical description of the aerothermodynamic flow is presented. A multi zone approach is used, solving, independently, the Euler or Navier-Stokes flow equations of the different flow regions. The illustrations give detailed results concerning aerothermodynamic characteristics and reentry parameters. ESA KEY STRUCTURES MECHANICAL ISSUES OF THE EUROPEAN SPACE STATION AND PLATFORM PROGRAM COLUMBUS S. Gazey and E. Winkelhoff 1988 10 p Presented at the Spacecraft Structures and Mechanical Testing Conference, Noordwijk, Netherlands, 19-21 Oct. 1988 (MBB-UD-0041-88-PUB; OTN-010456; ETN-89-95334) Avail: NTIS HC A02/MF A01 The main technical features of the Columbus space segment are discussed. The attached pressurized module (APM), integrated into NASA's Space Station Freedom; the man tended free flyer (MTFF) - Europe's first step into autonomy in space; and the polar platform (PPF), are described. The requirements for long life in orbit operation are considered: more realistic APM design loads must be determined to define maximum allowable launch mass; Columbus flight configuration responses to in-orbit operation loads must be determined by advanced nonlinear analysis tools; protection of the crew and subsystems against meteoroids and space debris are necessary, as well as analytical tools and test facilities to verify the required probability of nonpenetration of the modules; and repair procedures and maintenance tools have to ESA be developed to ensure in-orbit structural integrity. INTELLIGENT MULTI-SENSOR INTEGRATIONS Final Report Richard A. Volz, Ramesh Jain, and Terry Weymouth 1989 32 p 3 Aug. (Contract NAG2-350; JPL-958086) (NASA-CR-185846; NAS 1.26:185846) Avail: NTIS HC A03/MF A01 CSCL 14B Growth in the intelligence of space systems requires the use and integration of data from multiple sensors. Generic tools are being developed for extracting and integrating information obtained from multiple sources. The full spectrum is addressed for issues ranging from data acquisition, to characterization of sensor data, to adaptive systems for utilizing the data. In particular, there are three major aspects to the project, multisensor processing, an adaptive approach to object recognition, and distributed sensor system integration. N89-28563# Sira Inst. Ltd., Chislehurst (England). Author A MEDIUM RESOLUTION IMAGING SPECTROMETER FOR M. A. Cutter, D. R. Lobb, Y. Ramon, G. Ratier, and J. L. Bezy (ETN-89-95235) Avail: NTIS HC A02/MF A01 1989 The design for the Medium Resolution Imaging Spectrometer (MERIS), proposed as a candidate core instrument for the European polar platform scheduled for launch in 1997, is described. The instrument has a spectral range of 400 to 1050 nm, a swath width of 1500 km, spectral resolution of 1.25 nm, and spatial resolution of 260 m. Spectral bands, and spectral and spatial resolution, can be reprogrammed in orbit. The instrument has applications in the fields of marine, land and atmospheric research. MERIS provides high radiometric performance at medium spatial resolution, which is appropriate primarily for oceanographic measurements. The instrument also offers the capability of monitoring high albedo targets which are of value in remote sensing of ice, land and coastal regions. ESA N89-28564# Messerschmitt-Boelkow-Blohm G.m.b.H., Ottobrunn (Germany, F.R.). PROPOSED CONCEPTS FOR A ADVANCED OPTICAL B. Kunkel, F. Blechinger, J. L. Bezy, G. Ratier, D. R. Lobb, M. A. (ETN-89-95236) Avail: NTIS HC A03/MF A01 The technical concepts of a visible/infrared imaging radiometer and an infrared vertical sounder (payloads of the Meteosat second generation) are described. All instruments are assumed to be operated on a 3-axis stabilized satellite, while the current system is a spin stabilized satellite. The imaging radiometer has 2 visible and 6 infrared channels for cloud tracking and sea surface/cloud top temperature measurements (compared to currently 3), partly split channels at reduced bandwith and 2 km instantaneous field-of-view (angular resolution). The proposed solution of a hybrid scan system, involving 2-axis mechanical scan combined with a north/south fine scan (by means of short detector arrays), is presented. The infrared sounder is required to scan the Earth disc in 16 km instantaneous field-of-view (angular resolution) intervals and 18 channels for water vapor and temperature profiling. The proposed technical concept uses a spectrometer for spectral channel multiplexing rather than a filter wheel as the standard principle for such instruments. It is also foreseen for the GOES-Next. Both instruments provide promising performance data. Imager can be used in the fields of oceanography, vegetation mapping, radiation budget determination for climatology and environmental monitoring. ESA 20 SPACECRAFT PROPULSION AND POWER Includes main propulsion systems and components, e.g., rocket engines; and spacecraft auxilliary power sources. For related information see also 07 Aircraft Propulsion and Power, 28 Propellants and Fuels, 44 Energy Production and Conversion, and 15 Launch Vehicles and Space Vehicles. N89-28565*# National Academy of Sciences - National Research ADVANCED POWER SOURCES FOR SPACE MISSIONS (Contract F49620-85-C-107) Washington (NASA-TM-101811; NAS 1.15:101811; LC-88-63907; Approaches to satisfying the power requirements of space-based Strategic Defense Initiative (SDI) missions are studied. The power requirements for non-SDI military space missions and for civil space missions of the National Aeronautics and Space Administration (NASA) are also considered. The more demanding SDI power requirements appear to encompass many, if not all, of the power requirements for those missions. Study results indicate that practical fulfillment of SDI requirements will necessitate substantial advances in the state of the art of power technology. SDI goals include the capability to operate space-based beam weapons, sometimes referred to as directed-energy weapons. Such weapons pose unprecedented power requirements, both during preparation for battle and during battle conditions. The power regimes for these two sets of applications are referred to as alert mode and burst mode, respectively. Alert-mode power requirements are presently stated to range from about 100 kW to a few megawatts for cumulative durations of about a year or more. Burst-mode power requirements are roughly estimated to range from tens to hundreds of megawatts for durations of a few hundred to a few thousand seconds. There are two likely energy sources, chemical and nuclear, for powering SDI directed-energy weapons during the alert and burst modes. The choice between chemical and nuclear space power systems depends in large part on the total duration during which power must be provided. Complete study findings, conclusions, and eight recommendations are reported. Author (NASA-CR-183743; NAS 1.26:183743; TWR-18915) Avail: NTIS HC A03/MF A01 CSCL 21H Testing to evaluate Redesigned Solid Rocket Motor igniter heater electromagnetic interference (EMI) effects on the Safe and Arm (S and A) device was completed. It was suspected that EMI generated by the igniter heater and its associated electromechanical relay could cause a premature firing of the NASA Standard Initiators (NSIS) inside the S and A. The maximum voltage induced into the NSI fire lines was 1/4 of the NASA specified no-fire limit of one volt (SKB 26100066). As a result, the igniter heaters are not expected to have any adverse EMI effects on the NSIS. The results did show, however, that power switching causes occasional high transients within the igniter heater power cable. These transients could affect the sensitive equipment inside the forward skirt. It is therefore recommended that the electromechanical igniter heater relays be replaced with zero crossing solid state relays. If the solid state relays are installed, it is also recommended that they be tested for EMI transient effects. Author N89-28568*# National Aeronautics and Space Administration. Marshall Space Flight Center, Huntsville, AL. STATIC AND DYNAMIC DEFLECTION STUDIES OF THE SRM AFT CASE-NOZZLE JOINT David C. Christian, Lawrence D. Kos, and Isaias Torres 1989 37 p (NASA-TM-100373; NAS 1.15:100373) Avail: NTIS HC A03/MF A01 CSCL 21H Aug. The redesign of the joints on the solid rocket motor (SRM) has prompted the need for analyzing the behavior of the joints using several different types of analyses. The types of analyses performed include modal analysis, static analysis, transient response analysis, and base driving response analysis. The forces used in these analyses to drive the mathematical model include SRM internal chamber pressure, nozzle blowout and side forces, shuttle vehicle lift-off dynamics, SRM pressure transient rise curve, gimbal forces and moments, actuator gimbal loads, and vertical and radial bolt preloads. The math model represented the SRM from the aft base tangent point (1,823.95 in) all the way back to the nozzle, where a simplified, tuned nozzle model was attached. The new design used the radial bolts as an additional feature to reduce the gap opening at the aft dome/nozzle fixed housing interface. Author N89-28569# Pisa Univ. (Italy). Facolta di Ingegneria. Niccola Kutufa 1988 224 p In ITALIAN The thermal exchange, gas side and total, of a rocket motor using regenerative cooling is studied. The combustion and dissociation chemical reactions are characterized. The NASA calculation program Gordon McBride was employed to identify the transport and thermodynamic properties of the combustion products. Motor configurations are studied and the global thermal flow is determined. The geometrical parameters of the cooling channels and its thermodynamical constraints are identified. ESA N89-28567* # Diane Garecht Jul. 1989 (Contract NAS8-30490) 227 P (NASA-CR-183740; NAS 1.26:183740; TWR-17639; DR-5-3; WBS-HQ601-20-10; ECS-SS-1858) Avail: NTIS HC A11/MF A01 CSCL 21H A primary objective of the technical evaluation motor program is to recover the case, igniter and nozzle hardware for use on the redesigned solid rocket motor flight program. Two qualification objectives were addressed and met on TEM-3. The Nylok thread locking device of the 1U100269-03 leak check port plug and the 1U52295-04 safe and arm utilizing Krytox grease on the barrier-booster shaft O-rings were both certified. All inspection and instrumentation data indicate that the TEM-3 static test firing conducted 23 May 1989 was successful. The test was conducted at ambient conditions with the exception of the field joints (set point of 121 F, with a minimum of 87 F at the sensors), igniter joint (set point at 122 F with a minimum of 87 F at sensors) and case-to-nozzle joint (set point at 114 F with a minimum of 87 F at sensors). Ballistics performance values were within specification requirements. Nozzle performance was nominal with typical erosion. The nozzle and the case joint temperatures were maintained at the heaters controlling set points while electrical power was supplied. The water and the CO2 quench systems prevented damage to the metal hardware. All other test equipment performed as planned, contributing to a successful motor firing. All indications are that the test was a success, and all expected hardware will be refurbished for the RSRM program. Author N89-28570*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. EVOLUTIONARY GROWTH FOR SPACE STATION FREEDOM ELECTRICAL POWER SYSTEM Matthew F. Marshall, Kerry L. McLallin, and Michael J. Zernic 1989 8 p Presented at the 24th Intersociety Energy Conversion Engineering Conference, Washington, DC, 6-11 Aug. 1989; cosponsored by IEEE, AIAA, ANS, ASME, SAE, ACS, and AIChE (NASA-TM-102339; E-5047; NAS 1.15:102339) Avail: NTIS HC A02/MF A01 CSCL 22B Over an operational lifetime of at least 30 yr, Space Station Freedom will encounter increased space station user requirements and advancing technologies. The space station electrical power system is designed with the flexibility to accommodate these emerging technologies and expert systems and is being designed with the necessary software hooks and hardware scars to accommodate increased growth demand. The electrical power system is planned to grow from the initial 75 kW up to 300 kW. The Phase 1 station will utilize photovoltaic arrays to produce the electrical power; however, for growth to 300 kW, solar dynamic power modules will be utilized. Pairs of 25 kW solar dynamic power modules will be added to the station to reach the power growth level. The addition of solar dynamic power in the growth phase places constraints in the initial space station systems such as guidance navigation and control, external thermal, truss structural stiffness, computational capabilities and storage which must be planned-in in order to facilitate the addition of the solar dynamic modules. Author N89-28571*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. ION OPTICS FOR HIGH POWER 50-cm-DIAM ION Vincent K. Rawlin and Marc G. Millis Sep. 1989 23 p Presented at the 25th Joint Propulsion Conference, Monterey, CA, 10-12 Jul. 1989; cosponsored by AIAA, ASME, SAE, and ASEE Previously announced in IAA as A89-47040 (NASA-TM-102143; E-4938; NAS 1.15:102143; AIAA-89-2717) Avail: NTIS HC A03/MF A01 CSCL 21C The process used at the NASA-Lewis to fabricate 30 and 50-cm-diameter ion optics is described. The ion extraction capabilities of the 30 and 50-cm diameter ion optics were evaluated on divergent field and ring-cusp discharge chambers and compared. Perveance was found to be sensitive to the effects of the type and power of the discharge chamber and to the accelerator electrode hole diameter. Levels of up to 0.64 N and 20 kW for thrust and input power, respectively, were demonstrated with the divergent-field discharge chamber. Thruster efficiencies and specific impulse values up to 79 percent and 5000 sec., respectively, were achieved with the ring-cusp discharge chamber. 23 CHEMISTRY AND MATERIALS (GENERAL) E.R. N89-28572# Computer Sciences Corp., Research Triangle Park, MATERIALS AEROMETRIC DATABASE FOR USE IN Ruen-Tai Tang, P. Michael Barlow, and Paul Waldruff Apr. 1989 29 p (Contract EPA-68-01-7365) (PB89-181259; EPA/600/3-89/031) Avail: NTIS HC A03/MF A01 CSCL 07D Meteorological and air quality data acquired at field exposure sites were accessed into the Materials Aerometric Database (MAD). The National Acid Precipitation Assessment Program (NAPAP) will use the MAD to develop damage functions for materials exposed at the sites; these functions then will be used in preparing NAPAP integrated assessment reports to Congress. The MAD data cover as many as six and a half years at five materials exposure sites in the eastern United States. Conservative techniques based on secondary-site data, regression predictions, and other information were applied to the MAD to enhance the quality and usability of the database. 24 COMPOSITE MATERIALS Author Includes physical, chemical, and mechanical properties of laminates and other composite materials. For ceramic materials see 27 Nonmetallic Materials. N89-28573# Rockwell International Corp., Golden, CO. (Contract DE-AC04-76DP-03533) (DE89-013524; RFP-4297-Supp-2; CONF-890789-1-Supp-2) Avail: NTIS HC A03/MF A01 Comprehensive bibliographies on the subject of Acoustic Emission (AE) from composites were compiled for the First and Second International Symposiums on Acoustic Emission from Reinforced Composites. The current bibliography is the third in the series. It presents 212 references of new material. The material is presented in the same format as previously used, which consists of a bibliographic section, an author index, and a subject index. Although not all-inclusive, this series of bibliographies presents a compilation of the bulk of world literature published on the subject of acoustic emission from composites. DOE N89-28574# Naval Postgraduate School, Monterey, CA. Dept. of Mechanical Engineering. COMPOSITE MATERIAL REPAIR AND RELIABILITY M.S. Shmuel Maman Mar. 1989 160 p (AD-A209150) Avail: NTIS HC A08/MF A01 CSCL 11/4 Composite structure repair methodology has been developed to specific applications (typically in small area and limited to secondary structure) and is being extended to Large Area Composite Structure Repair (with target extension to primary structures). Therefore, the repair becomes more critical because we get redistribution of stresses that can also affect the zones outside of the repair area. For this reason, an analytic evaluation of the repair's reliability has to be performed to define a parameter which reflects on the effectiveness of the repair. In this work, we establish a principal guideline to evaluate the redundancy and compare the reliability of the repair to the reliability of the parent structure (i.e., the structure in the undamaged state). The approach adopted is to utilize structural finite element analysis to compute the state and of the candidate repaired state. The reliability of these two spatially non-uniform stresses is computed by a probabilistic failure criterion. Thus, we can optimize the repair configuration by varying the strength and the stiffness of any element in the repair site by varying the lamination angles, and selectively using hybrid materials. GRA A NEW METHOD FOR MONITORING CURE AND MOBILITY IN EPOXY MATRIX AND FIBER/EPOXY INTERPHASES Final Report 3 р C. S. P. Sung 28 Mar. 1989 The objective of this contract was to develop a new method based on reactive labelling technique for monitoring cure and mobility in epoxy matrix and fiber/epoxy interphases. These reactive labels were chosen to exhibit spectral changes in the region of UV-visible and fluorescence spectra where the polymerizing matrix has little absorption or emission. In this method, advantage was taken of the magnified effects of the substituent changes in the para and para (prime) positions of conjugated aromatic reactive labels on the UV-visible and fluorescence spectra. This method was applied to characterize the kinetics and mechanisms of the cure in epoxy networks and in polyurethanes, the imidization process in polyimides, and the acylation in polyamides. One particular advantage of this method is that one can often distinguish between several cure species in some polymers. This advantage makes it possible to follow cure composition throughout the cure process and to analyze the kinetics and the mechanisms of several consecutive polymerization steps in some polymers. GRA N89-28577# Ohio State Univ., Columbus. Dept. of Metallurgical Engineering and Materials Science. EXPLANATORY RESEARCH ON THE PROTECTION OF CARBON-CARBON COMPOSITES AGAINST OXIDATION AT VERY HIGH TEMPERATURES (GREATER THAN 3000 F) WITH ENGEL-BREWER AND OTHER INTERMETALLIC COMPOUNDS Final Report George StPierre Jun. 1988 205 p (Contract N00014-86-K-0130; RF7-65208) (AD-A207907) Avail: NTIS HC A10/MF A01 CSCL 11/3 Iridium-based coatings have been proposed for the protection of carbon/carbon composites against oxidation at temperatures greater than 1600 C. However, Ir exposed to an oxidizing atmosphere at such high temperatures reacts with oxygen to form volatile oxides. Alloying Ir with a reactive element that forms a protective scale was proposed as a method to prevent the evaporation of Iridium base coatings. Hafnium and Zr were suggested as possible alloying elements. Investigations of the Ir-Hf and the Pt-Zr systems, however, have shown that Hf and Zr are only moderately protective. In both systems the reactive element, Hf and Zr, did not form a highly protective oxide scale. Aluminum is another possible alloying addition for the prevention of evaporation of the noble metal suboxides. Samples of C/C composite would be coated with HfC and then a layer of Iridium would be applied. It was demonstrated that an adherent layer of Ir3Hf can be grown between these coatings. The surface of the Ir would be impregnated with Al and Cr. GRA N89-28578# Ceramic Process Systems Corp., Cambridge, MA. HIGHLY ORIENTED FIBER REINFORCED CERAMIC COMPOSITES Final Report, 1 Aug. 1988 - 31 Jan. 1989 Ran-Rong Lee, James D. Hodge, Wen-Cheng J. Wei, John Halloran, and Frances Schutzberg 31 Mar. 1989 79 p (Contract F49620-88-C-0104; AF Proj. 3005) (AD-A208119; CPS-89-004; AFOSR-89-0531TR) Avail: NTIS HC A05/MF A01 CSCL 11/4 Highly dense SiC-AIN alloys having unique microstructures and a fracture toughness up to 6 MPam 1/2 were successfully produced by pressureless sintering of commercially available SiC and AIN powders. Appropriate sintering aids, sintering temperatures, sintering period and sintering conditions were identified. The sintered SiC-AIN alloys can achieve a single phase solid solution after an appropriate thermal treatment. The lattice constants of the solid solution varied linearly with SIC/AIN ratio. Optimized annealing yielded decomposition of the solid solution and formed a unique microstructure, which was composed of equiaxed grains with modulated features, heavily faulted elongated grains and very clean grain boundaries. GRA N89-28579*# National Aeronautics and Space Administration. Langley Research Center, Hampton, VA. FIVE YEAR GROUND EXPOSURE OF COMPOSITE MATERIALS USED ON THE BELL MODEL 206L FLIGHT SERVICE EVALUATION Donald J. Baker (Army Aviation Research and Development Command, Hampton, VA.) Jul. 1989 93 p (NASA-TM-101645; NAS 1.15:101645; AVSCOM-TM-89-B-007) Avail: NTIS HC A05/MF A01 CSCL 11D Part of the results of a U.S. Army/NASA-Langley sponsored research program to establish the long term-term effects of realistic ground based exposure on advanced composite materials is presented. Residual strengths and moisture absorption as a function of exposure time and exposure location are reported for four different composite material systems that were exposed for five years on the North American Continent. Author Labs., Melbourne ANALYSIS AND REPAIR OF IMPACT DAMAGED COMPOSITES J. Paul and R. Jones Jan. 1989 44 P (ARL-Struct-R-435; AR-005-570) Copyright Avail: NTIS HC A03/MF A01 The repair of impact damaged graphite/epoxy composite (Contract BMVg-T/RF52/80025/81524) (BMVg-FBWT-88-2; BMVg-RUFO-5(ALT); ETN-89-94412) Copyright Avail: Dokumentations- und Fachinformationzentrum der Bundeswehr, Friedrich-Ebert-Allee 34, 5300 Bonn 1, Fed. Republic of Germany, 60 DM Moisture diffusion into graphite-epoxy composites is studied using a radiotracer technique. Diffusion parameters and maximum moisture content of the carbon fiber reinforced plastic samples are measured. Tritiated water tracer, profile sectioning technique and liquid scintillation counting are applied. The diffusion coefficients, activation energies and frequency factors are determined for the composites fibredux 913C and 914C and fiberite 1076, as well as the maximum moisture content for different relative humidities and absorption constants. The results can be used to calculate moisture absorption/desorption curves, as a function of time, for various relative humidities and temperatures. General rules for diffusion and moisture absorption of both composites are deduced. Neutron induced autoradiography measurements show a high concentration of diffused water at the carbon fiber-resin interface. ESA N89-28582# Paris VI Univ. (France). Lab. d'Acoustique et H. Dumontet, A. Guiraud, A. Thionnet, and Y. Xu Sep. 1988 100 p In FRENCH Prepared in cooperation with Aerospatiale Usines de Toulouse, France (Contract DRET-87-34-325-00-470-7501) A calculation method for constraints is presented, based on a two scale asymptotic development technique associated to a boundary layer theory and expressed in terms of displacement. The numerical implementation and algorithms are described. The results of computerized simulations are detailed for carbon-epoxy specimens with varying plys and orientation. The influence of structural factors on the results are discussed. ESA N89-28583 National Physical Lab., Teddington (England). Div. of Materials Applications. MEASUREMENT OF MODE 1 AND MODE 2 STRAIN ENERGY RELEASE RATES: A VAMAS ROUND ROBIN PROJECT ON DELAMINATION OF COMPOSITE MATERIALS 78 p M. W. Money Mar. 1989 The study of delamination in composite materials, performed at the National Physical Laboratory to determine G sub C values for a variety of test geometries in fracture modes 1 and 2 is reported. Materials studied include aligned carbon fiber/epoxy, aligned glass fiber/epoxy and woven glass fiber/epoxy. The glass reinforced materials are considered in both 3 mm and 20 mm thickness. The test methods and the different analytical techniques used to evaluate the fracture parameter are discussed. ESA |