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Failure of a fiber composite lamina under three-dimensional stresses

Description: The efficient use of thick-section fiber composites requires a proven three-dimensional failure model. Numerous failure criteria have been proposed, but the lack of critical experimental results makes it difficult to assess the accuracy of these models. It is shown that the various predictions for failure of a lamina due to the simple state of uniaxial stress plus superposed hydrostatic pressure are disparate. These differences are sufficient to allow evaluation of failure criteria using data that has the normal scatter found for composite materials. A high-pressure test system for fiber composites is described and results for the effects of pressure on the transverse and longitudinal compression strengths of a carbon fiber/epoxy lamina are discussed. Results are compared with a few representative failure models.
Date: August 31, 1999
Creator: DeTeresa, S. J.
Partner: UNT Libraries Government Documents Department

Aging and PBX 9502

Description: Components made from PBX 9502, an insensitive high explosive formulated with triaminotrinitrobenzene (TATB) and Kel-F 800 binder, have been in service for nearly two decades. Since that time, samples have been destructively evaluated to determine if potential changes that might affect safety, reliability, or performance have occurred in the high explosive with time. Data from routine, historical testing is reported elsewhere. This paper focuses on specific tests conducted to evaluate the effects of natural aging on handling sensitivity (through the small-scale tests of Human Electrostatic Discharge, friction, and Drop Weight Impact), compressive strength, and thermal ignition. Also reported are the effects of a radiation environment on TATB. Small-scale sensitivity tests show no differences between aged and unaged material. Observed differences in compressive strength behavior are attributed to conditions of original material rather than aging effects. Thermal ignition by flame and laser methods showed no changes between aged and unaged material. Extreme levels of radiation are shown to have only minimal effects in explosive response tests. PBX 9502 is concluded, once again, to be a very stable material, aging gracefully.
Date: December 31, 1998
Creator: Skidmore, C.B.; Idar, D.J.; Buntain, G.A.; Son, S.F. & Sander, R.K.
Partner: UNT Libraries Government Documents Department

Bleed water testing program for controlled low strength material

Description: Bleed water measurements for two Controlled Low Strength Material (CLSM) mixes were conducted to provide engineering data for the Tank 20F closure activities. CLSM Mix 1 contained 150 pounds of cement per cubic yard whereas CLSM Mix 2 contained 50 pounds per cub yard. SRS currently used CLSM Mix 2 for various applications. Bleed water percentages and generation rates were measured along with flow and compressive strength. This information will be used to select a mix design for the Tank 20F closure activities and to establish the engineering requirements, such as, lift height, time required between lifts and quantity of bleed water to be removed from the tank during the placement activities. Mix 1 is recommended for placement within Tank 20F because it has better flow characteristics, less segregation, lower percentage of bleed water and slightly higher strength. Optimization of Mix 1 was beyond the scope of this study. However, further testing of thickening additives, such as clays (bentonite), sodium silicate or fine silicas maybe useful for decreasing or eliminating bleed water.
Date: November 12, 1996
Creator: Langton, C.A.
Partner: UNT Libraries Government Documents Department

Mechanical properties of a structural polyurethane foam and the effect of particulate loading

Description: The room temperature mechanical properties of a closed-cell, polyurethane encapsulant foam have been measured as a function of foam density. Tests were performed on both unfilled and filler reinforced specimens. Over the range of densities examined, the modulus of the unloaded foam could be described by a power-law relationship with respect to density. This power-law relationship could be explained in terms of the elastic compliance of the cellular structure of the foam using a simple geometric model found in the literature. The collapse stress of the foam was also found to exhibit a power-law relationship with respect to density. Additions of an aluminum powder filler increased the modulus relative to the unfilled foam.
Date: April 1, 1998
Creator: Goods, S.H.; Neuschwanger, C.L. & Whinnery, L.L.
Partner: UNT Libraries Government Documents Department

Compressive strength of masonry (f{sub m}{prime}) for the Oak Ridge Y- 12 Plant, Hollow Clay Tile Walls

Description: Prism tests have been performed on the HCT walls. The three groups of data were treated as separate data points and averaged. The recommended effective compressive strengths for HCT walls are 735 psi for single wythe 6- and 8-in. walls, and 495 psi for the double wythe 13-in. walls.
Date: April 17, 1995
Creator: Fricke, K.E. & Flanagan, R.D.
Partner: UNT Libraries Government Documents Department

183-H Basin sludge treatability test report

Description: This document presents the results from the treatability testing of a 1-kg sample of 183-H Basin sludge. Compressive strength measurements, Toxic Characteristic Leach Procedure, and a modified ANSI 16.1 leach test were conducted
Date: December 31, 1995
Creator: Biyani, R.K.
Partner: UNT Libraries Government Documents Department

Effect of angle-ply orientation on compression strength of composite laminates

Description: An experimental program was initiated to investigate the effect of angle-ply orientations on the compressive strength (X{sub 1C}) of 0{degree} plies in fiber reinforced composite laminates. Graphite fiber-reinforced epoxy test coupons with the generic architecture [0{sub 2}/{+-}{theta}] (where {theta} varied between 0{degree} and 90{degree}) and for the quasi-isotropic architecture were evaluated. The effective compressive strength of the 0{degree} plies varied considerably. The results were related to the Poisson's ratios of the laminates with high Poisson's ratios leading to high transverse tensile strains in the test coupons and lower than expected strengths. Specimens with the [O{sub 2}/{+-}30] architecture had both the highest Poisson's ratio and the lowest calculated ply-level compression strength for the 0{degree} plies. This work has implications in the selection of composite failure criterion for compression performance, design of test coupons for acceptance testing, and the selection of laminate architectures for optimum combinations of compressive and shear behavior. Two commonly used composite failure criteria, the maximum stress and the Tsai-Wu, predict significantly different laminate strengths depending on the Poisson's ratio of the laminate. This implies that the biaxial stress state in the laminate needs to be carefully considered before backing out unidirectional properties.
Date: March 1, 1999
Creator: DeTeresa, S J & Hoppel, C P
Partner: UNT Libraries Government Documents Department

Measurement of the stress/strain response of energetic materials as a function of strain rate and temperature: PBX 9501 and Mock 9501

Description: We have measured the stress/strain behavior of PBX 9501, Mock 900-21 and two new mocks consisting of monoclinic granular sugar embedded in (1) a BDNPA-F/estane binder (a 9501 material mock; a hard organic crystal embedded in a plastic) and (2) neat estane (an LX-14 mock) at strain rates from 10{sup -3} to 10{sup -1}, at two L/D`s and at two temperatures (25 and 60 C). We find that the compressive strength falls with increasing temperature and rises with increasing strain rate. We also find that the new 9501 sugar mock most closely resembles the behavior of the 9501 explosive and differences may be attributable to the different ages of the estane binder used.
Date: September 1, 1995
Creator: Funk, D.J.; Laabs, G.W.; Peterson, P.D. & Asay, B.W.
Partner: UNT Libraries Government Documents Department

Yield strength and stress relaxation data for an adhesive used in butt joint tests

Description: Mechanical property data are reported for Epon 828/T403, an amine-cured epoxy adhesive. Data include compression modulus, compression yield strength and compression stress relaxation as a function of stress level, strain rate, and temperature and Mode I fracture toughness as a function of temperature. This data was generated to support a study investigating how temperature effects joint strength and the corresponding interface comer fracture toughness for adhesively bonded butt joints.
Date: July 1, 1995
Creator: Guess, T.R. & Reedy, E.D. Jr.
Partner: UNT Libraries Government Documents Department

Additional Characterization of Min-K TE-1400 Thermal Insulation

Description: Min-K 1400TE (Thermal Ceramics, Augusta, Georgia) insulation material was further characterized at Oak Ridge National Laboratory (ORNL) for use in structural applications under gradient temperature conditions in an inert environment. Original characterization of Min-K was undertaken from April 1997 to July 2008 to determine its high temperature compressive strength and stress relaxation behavior up to 900 C in helium along with the formulation of a general model for the mechanical behavior exhibited by Min-K under these conditions. The additional testing described in this report was undertaken from April 2009 to June 2010 in an effort to further evaluate the mechanical behavior of Min-K when subjected to a variety of conditions including alternative test temperatures and time scales than previously measured. The behavior of Min-K under changing environments (temperature and strain), lateral loads, and additional isothermal temperatures was therefore explored.
Date: January 1, 2011
Creator: Hemrick, James Gordon & King, James
Partner: UNT Libraries Government Documents Department

Pelletization of fine coals. Technical progress report, March 1, 1992--May 31, 1992

Description: The first step consisted of producing a batch of seed pellets (in the size range {minus}4.75+4.00 mm) by pelletizing of 200 g of ground coal with desired additives (surface active agents and binders) and moisture content for 800 revolutions. The seed pellets are obtained by sieving the output from the batch drum. The second step involved the production of finished size pellets by layering the seed pellets with stepwise addition of moist feed which is again produced with desired additives and moisture content. Specifically, 25 g of the {minus}4.75+4.00 mm seed pellets are placed in the drum and 20 g of moist fluffy feed is added every 80 revolutions for five times. After 400 revolutions the pellets are sieved on the 4.75 mm screen and the screen undersize which corresponds to new seeds generated during the layering cycles is discarded. Now, 30 g of moist fluffy feed is added every 50 revolutions for five more cycles. These layered pellets are sieved again and the {minus}9.5+8.00 mm pellets. Coal agglomerates produced by the above described technique are nice and spherical. With our past experience with iron ore pelletization we learnt that as long as sufficient fluffy feed is available for the consumption by the seed pellets, they generally grow by forming layers consuming the feed rather than grow by coalescence. This is found to be true in the case of coal also. Growth by coalescence of coal pellets is found to yield raspberry type uneven agglomerates. After ascertaining the possibility of producing nice spherical pellets, several experiments have been conducted to develop the above standard procedure for making pellets in a reproducible way and testing them for their quality.
Date: September 1, 1992
Creator: Sastry, K. V. S.
Partner: UNT Libraries Government Documents Department

Test plan for buried waste containment system materials

Description: The objectives of the FY 1997 barrier material work at the Idaho National Engineering and Environmental Laboratory are to (1) select a waste barrier material and verify that it is compatible with the Buried Waste Containment System Process, and (2) determine if, and how, the Buried Waste Containment System emplacement process affects the material properties and performance (on proof of principle scale). This test plan describes a set of measurements and procedures used to validate a waste barrier material for the Buried Waste Containment System. A latex modified proprietary cement manufactured by CTS Cement Manufacturing Company will be tested. Emplacement properties required for the Buried Waste Containment System process are: slump between 8 and 10 in., set time between 15 and 30 minutes, compressive strength at set of 20 psi minimum, and set temperature less than 100{degrees}C. Durability properties include resistance to degradation from carbonate, sulfate, and waste-site soil leachates. A set of baseline barrier material properties will be determined to provide a data base for comparison with the barrier materials when tested in the field. The measurements include permeability, petrographic analysis to determine separation and/or segregation of mix components, and a set of mechanical properties. The measurements will be repeated on specimens from the field test material. The data will be used to determine if the Buried Waste Containment System equipment changes the material. The emplacement properties will be determined using standard laboratory procedures and instruments. Durability of the barrier material will be evaluated by determining the effect of carbonate, sulfate, and waste-site soil leachates on the compressive strength of the barrier material. The baseline properties will be determined using standard ASTM procedures. 9 refs., 1 fig., 2 tabs.
Date: March 1, 1997
Creator: Weidner, J. & Shaw, P.
Partner: UNT Libraries Government Documents Department

How geometric details can affect the strength of adhesive lap joints

Description: The durability of adhesively bonded joints--when utilized as blade attachments--has a significant impact on the performance of wind turbines. Accordingly, there is interest in determining how geometric details affect the strength of these joints. Finite element analyses were performed to aid in the selection of three composite-to-metal joint geometries for compressive axial testing. Both monotonic and low-cycle fatigue tests were conducted. Analysis and testing of these joints provide insight into the effects of adding extra adhesive to the end of the bond or tapering the metal adherend. The issue of whether the relative performance of different joints in monotonic tests can be used to predict the relative fatigue strength of these joints is also addressed.
Date: December 31, 1996
Creator: Metzinger, K.E. & Guess, T.R.
Partner: UNT Libraries Government Documents Department

Investigation of the reduction of NiAl{sub 2}O{sub 4}. 1: Neutron diffraction studies

Description: In-situ metal-ceramic composites consisting of Ni particles embedded in alumina matrices were obtained by the partial reduction of NiAl{sub 2}O{sub 4}. The volume shrinkage that accompanies the reduction reaction generates residual stresses. Neutron diffraction studies were performed for the first time at various temperatures to study the evolution of phases in situ during reduction and to determine their stress state. It was determined that compressive stresses of several hundred MPa in magnitude can be generated inside the unreduced part of spinel. It was also found that the stress generation is strongly influenced by material and processing variables such as reduction temperature and the initial density of spinel. The diffraction results were then compared to finite element calculations and a reasonable agreement was obtained.
Date: September 1, 1998
Creator: Uestuendag, E.; Hanan, J.C.; Clausen, B.; Bourke, M.A.M.; Sass, S.L. & Barbieri, T.J.
Partner: UNT Libraries Government Documents Department

Effects of thermomechanical processing on the resulting mechanical properties of 6101 aluminum foam

Description: Porous materials represent a tremendous weight savings for light-weight structural applications. The fabrication path can play a critical role in the resulting properties. High porosity aluminum was fabricated in a number of ways. The starting material was a cast 6101 aluminum that had a relative density of 9.8%. The cast aluminum block was compressed by uniaxial, biaxial, and triaxial densification. Uniaxial compression was done at room temperature and 200 C. Biaxial compression was achieved by unidirectional rolling at room temperature and 200 C. Triaxial compression was done by cold isostatic pressing at 3.4, 6.7, and 34 MPa (0.5, 1.0, and 5.0 ksi). Metallography and mechanical test specimens were machines from the processed bars. The mechanical properties showed that the relative yield strength depended both on relative density and processing temperature.
Date: December 1, 1998
Creator: Margevicius, R.W.; Stanek, P.W. & Jacobson, L.A.
Partner: UNT Libraries Government Documents Department

Optimization of hydraulic cement admixture waste forms for sodium-bearing, high aluminum, and high zirconium wastes

Description: A three-way blend of portland cement, blast furnace slag, and fly ash was successfully tested on simulated acidic high sodium, aluminum, and zirconium low-level wastes (LLW). Grout cubes were prepared at various waste loadings to maximize loading while meeting compressive strength and leach resistance requirements. For sodium LLW, a 21% waste loading achieves a volume reduction of 3.3 and a compressive strength of 2750 pounds per square inch while meeting leach, mix, and flow requirements. It was found that the sulfur in the slag reduces the chromium leach rate below regulatory limits. For aluminum LLW, a 10% waste loading achieves a volume reduction of 8.5 and a compressive strength of 4.50 pounds per square inch while meeting leach requirements. Likewise for zirconium LLW, a 21% waste loading achieves a volume reduction of 8.3 and a compressive strength of 3570 pounds per square inch.
Date: August 1, 1997
Creator: Herbst, A.K.
Partner: UNT Libraries Government Documents Department

SEM studies of stressed and irradiated Climax Stock quartz monzonite

Description: In an effort to find the mechanism by which gamma irradiation weakens the unconfined compressive strength of Climax Stock quartz monzonite (CSQM), sections of rock which had been irradiated and loaded to near failure were studied by scanning electron microscopy and compared to sections of rock which had been loaded but not irradiated. The quantities measured and compared were numbers and lengths of microfractures in the rock. We found that the crack parameters depended neither on irradiation treatment nor even on stress history, except in one sample which actually failed. By comparison to cracks counted in other granites by other workers, the crack statistics on CSQM are much noisier and much less indicative of stress history. CSQM is structurally more heterogeneous than the other granites, which is probably the cause of the greater noise level. 12 references, 3 figures, 5 tables.
Date: February 1, 1984
Creator: Beiriger, J.M. & Durham, W.B.
Partner: UNT Libraries Government Documents Department

Admixture enhanced controlled low-strength material for direct underwater injection with minimal cross-contamination

Description: Commercially available admixtures have been developed for placing traditional concrete products under water. This paper evaluates adapting anti-washout admixture (AWA) and high range water reducing admixture (HRWRA) products to enhance controlled low-strength materials (CLSMs) for underwater placement. A simple experimental scale model (based on dynamic and geometric similitude) of typical grout pump emplacement equipment has been developed to determine the percentage of cementing material washed out. The objective of this study was to identify proportions of admixtures and underwater CLSM emplacement procedures which would minimize the cross-contamination of the displaced water while maintaining the advantages of CLSM. Since the displaced water from radioactively contaminated systems must be subsequently treated prior to release to the environment, the amount of cross-contamination is important for cases in which cementing material could form hard sludges in a water treatment facility and contaminate the in-place CLSM stabilization medium.
Date: March 1, 1997
Creator: Hepworth, H.K.; Davidson, J.S. & Hooyman, J.L.
Partner: UNT Libraries Government Documents Department

Mechanical Properties of a Metal Powder-Loaded Polyurethane Foam

Description: Quasi-static compression tests have been performed on polyurethane foam specimens. The modulus of the foam exhibited a power-law dependence with respect to density of the form: E* {proportional_to} {rho}*{sup n}, where n = 1.7. The modulus data is well described by a simple geometric model (attributed to the work of Gibson and Ashby) for closed-cell foam in which the stiffness of the foam is governed by the flexure of the cell struts and cell walls. The compressive strength of the foam is also found to follow a power-law behavior with respect to foam density. In this instance, Euler buckling is used to rationalize the density dependence. The modulus of the polyurethane foam was modified by addition of a gas atomized, spherical aluminum powder. Additions of 30 and 50 weight percent of the powder significantly increased the foam modulus. However, there were only slight increases in modulus with 5 and 10 weight percent additions of the metal powder. Strength was also slightly increased at high loading fractions of powder. This increase in modulus and strength could be predicted by combining the above geometric model with a well-known model describing the effect on modulus of a rigid dispersoid in a compliant matrix.
Date: April 1, 1999
Creator: Neuschwanger, C. L.; Whinnery, L. L. & Goods, S. H.
Partner: UNT Libraries Government Documents Department

Influence of temperature and strain rate on the mechanical behavior of Adiprene L-100

Description: The effect of sample thickness, strain rate, and temperature on the mechanical response of Adiprene-L100 is presented. The compressive stress-train response of Adiprene-L100 was found to depend on both the applies train rate; 0.001 {le} {dot {var_epsilon}} {le} 7,000 s{sup {minus}1}, and the test temperature at high-rate; 77 {le} T {le} 298 K. Due to the slow, dispersive wave propagation in Adiprene-L100, thinner sample thicknesses are needed to assure uniform, uniaxial stress conditions within Hopkinson Bar samples; the optimal sample thickness being dependent on test temperature. Decreasing temperature from 298 to 77 K at 3,000 s{sup {minus}1} was found to increase the maximum flow stress in Adiprene-L100 from 10 to {approximately} 210 MPa.
Date: May 1, 1997
Creator: Gray, G.T. III; Blumenthal, W.R.; Trujillo, C.P. & Carpenter, R.W. II
Partner: UNT Libraries Government Documents Department

The effect of interface damage on the microbuckling of unidirectional fiber-reinforced composites

Description: Fiber microbuckling is the primary failure mechanism in unidirectional fiber-reinforced composites under compression. Due to processing or service conditions, damage (e.g., microcracks) exists at fiber/matrix interfaces. The effect of damage on the microbuckling of fibers is investigated in the present study. Based on the micromechanics analysis, the damage at interfaces is modeled as a linear spring against interface sliding, and the spring constant depends on the damage level. It is established that the critical strain for fiber microbuckling is relatively insensitive to the interface damage, but increases rapidly with the fiber volume fraction.
Date: September 1, 1997
Creator: Huang, Y.; Liu, C.; Stout, M.G. & Hwang, K.C.
Partner: UNT Libraries Government Documents Department