Showing papers in "Journal of Testing and Evaluation in 1985"
TL;DR: In this article, the detection of explosives with ion mobility spectrometry (IMS) using reactant ion (background) subtraction techniques and chloride ion/molecule reaction chemistry is discussed.
Abstract: The detection of explosives with ion mobility spectrometry (IMS) using reactant ion (background) subtraction techniques and chloride ion/molecule reaction chemistry is discussed. Data are presented for dinitrotoluene (DNT), trinitrotoluene (TNT), RDX (cyclonite), Composition B, and dynamite. Using a membrane inlet system, a man-portable IMS detector system is described which can be used as a point sampler with these techniques.
75 citations
TL;DR: A comprehensive constitutive law for a sand-asphalt mixture subjected to either compressive or tensile cyclic loading is developed in this article, where elastic, plastic, viscoelastic, and viscoplastic components are incorporated into the model as they are found to be simultaneously present during the loading process.
Abstract: A comprehensive constitutive law for a sand-asphalt mixture subjected to either compressive or tensile cyclic loading is developed. The elastic, plastic, viscoelastic, and viscoplastic strain components are incorporated into the model as they are found to be simultaneously present during the loading process. The various parameters of the model are extracted from a series of repeated uniaxial creep and creep-recovery experiments performed under either compressive or tensile constant stress. The experiments are conducted at constant temperature and at various stress levels, time periods, and number of cycles. The material law presentation is followed by a parametric study that is intended to illustrate the relative quantitative influence of various parameters on the resilient and residual strain components.
53 citations
TL;DR: In this article, a method is described for the determination of the distribution of strain within a specimen undergoing large finite, nonuniform deformations under plane strain compression, and the method has been applied to the hot deformation of an aluminum alloy.
Abstract: A method is described for the determination of the distribution of strain within a specimen undergoing large finite, nonuniform deformations under plane strain compression. The method has been applied to the hot deformation of an aluminum alloy. Results show that prior strain history has no effect on the strain distribution and that specimens of a larger tool width to specimen thickness ratio provide more homogeneous strain distributions. It is proposed that variations in stress-strain curves observed for different tool width to specimen thickness ratios arise from the inhomogeneity of deformation and that these variations are greater in work-hardening materials. Implications for metallographic studies are drawn.
42 citations
TL;DR: In this article, the composition and temperature dependence of the dynamic Young's modulus for the ordered B2 Co-Al, Fe-Al and Ni-Al aluminides has been investigated using the piezoelectric ultrasonic composite oscillator technique (PUCOT).
Abstract: The composition and/or temperature dependence of the dynamic Young's modulus for the ordered B2 Co-Al, Fe-Al, and Ni-Al aluminides has been investigated using the piezoelectric ultrasonic composite oscillator technique (PUCOT). The modulus has been measured in the composition interval 48.49 to 52.58 at. pct Co, 50.87 to 60.2 at. pct Fe, and 49.22 to 55.95 at. pct Ni for Co-Al, Fe-Al, and Ni-Al, respectively. The measured values for Co-Al are in the temperature interval 300 to 1300 K, while those for the other systems are for ambient temperature only. The data points show that Co-Al is stiffer than Fe-Al, which is stiffer than Ni-Al. The data points for Fe-Al and Ni-Al are slightly higher than those reported in the literature.
35 citations
TL;DR: A multispecies toxicity test using indigenous microorganisms is described in this paper, which is suitable for both laboratory and field, is inexpensive, replicates easily, and uses extremely inexpensive materials.
Abstract: A multispecies toxicity test is described that uses indigenous microorganisms. The test is suitable for both laboratory and field, is inexpensive, replicates easily, and uses extremely inexpensive materials. An additional advantage is the use of an important ecological rate process as an end point; therefore the test is superior to test using lethality as an end point. The test can be carried out using organisms collected from a site of interest or from a specific ecological resource area. Site-specific or synthetic dilution water may be used. The major drawback is a requirement for significant taxonomic ability. However, more general chemical measures such as ATP biomass, chlorophyll biomass, or heterotrophic index may substitute for species identification. Although this test has been used in a variety of freshwater ecosystems in the United States and has been validated to a limited degree in the People's Republic of China, a wider data base is required before it can be generally used.
21 citations
TL;DR: In this article, a simple procedure for the determination of the effective Young's modulus of rock is presented, which uses the elastic compliance calibration of fracture toughness test specimen geometry, and is measured with various sized three-point bend and compact tension specimens of granite.
Abstract: A simple procedure for the determination of the effective Young's modulus of rock is presented. The method uses the elastic compliance calibration of fracture toughness test specimen geometry. Specimen compliance is measured with various sized three-point bend and compact tension specimens of granite. The experimental results show that the deformation behavior of the granite is significantly nonlinear and the specimen compliance is dependent on the loading level. A sharply notched specimen is successfully used to determine the effective Young's modulus rather than a fatigue precracked one because of the strong effect of fatigue loading on the specimen compliance. The effective Young's modulus evaluated by the compliance method coincides well with the Young's modulus determined from uniaxial tension tests and shows no specimen size or geometry effects. The effect of water environment on the effective Young's modulus is also investigated by this method.
17 citations
TL;DR: In this paper, an experimental investigation was conducted to develop a test method and hardware for the purpose of characterizing the material behavior of coated glass fabrics for application in large roof structures.
Abstract: An experimental investigation was conducted to develop a test method and hardware for the purpose of characterizing the material behavior of coated glass fabrics for application in large roof structures. Because of the biaxial nature of stresses in fabric structures, an internally pressurized cylinder specimen was designed for use in a hydraulically actuated (MTS) testing machine. Biaxial cylinder fabrication and appropriate testing procedures were developed. Stress-strain and strength characteristics were determined for various fabric material types and material lots. Biaxial monotonic, step loading, stress rupture, and dynamic fatigue loading conditions were studied. Combined biaxial tensile plus shear loading were assessed by testing cylinders under biaxial and superimposed torsion loading conditions. The strength characteristics of damaged fabric materials were also extensively assessed.
14 citations
TL;DR: In this paper, a microprocessor-based system was developed to control varying temperature during material characterization tests, and four control zones were used in order to provide two-dimensional temperature control on a flat plate specimen.
Abstract: A microprocessor-based system has been developed to control varying temperature during material characterization tests. The system controls temperature independently over four zones. Four control zones are used in order to provide two-dimensional temperature control on a flat plate specimen. Specimen cooling is provided by forced air through shower head type nozzles.
12 citations
TL;DR: In this article, the influence of thickness and width on the elastic-plastic fracture toughness parameters: J value obtained from area under load/displacement curve JR, tearing modulus, and stress intensity factor corrected for plasticity KR.
Abstract: An investigation has been carried out to determine the influence of thickness and width on the elastic-plastic fracture toughness parameters: J value obtained from area under load/displacement curve JR, tearing modulus, and stress intensity factor corrected for plasticity KR. Compact tension specimens prepared from aircraft quality American Iran and Steel Institute (AISI) 4340 (Unified Numbering System [UNS] G43400) steel heat treated to a yield strength of 1000 MPa were used. All specimens satisfied the ASTM Test for JIc, a measure of Fracture Toughness (E 813) standard size requirements. This investigation demonstrates that when the specimens satisfy all ASTM standard size requirements, ductile fracture toughness JIc is independent of size. JIc values were found to vary a maximum of ±16% of mean value even in the present of some shear lips. Conversely, the tearing modulus was found to decrease as specimen thickness increased. A one to one relationship was found to exist between JR and JK, where JR is the J value calculated from the area under the load/displacement curve and JK is the J value computed from KR using the linear elastic fracture mechanics (LEFM) relationship.
12 citations
TL;DR: In this paper, the propagation of fissures sur des eprouvettes compactes circulaires de petites dimensions en aciers ferritiques dans le domaine de temperature de −192 a 427 C.
Abstract: Essais de propagation de fissures sur des eprouvettes compactes circulaires de petites dimensions en aciers ferritiques dans le domaine de temperature de −192 a 427 C. Bon accord des resultats sur l'acier a 9 Cr-1 Mo avec la methode de l'eprouvette multiple pour la determination de la limite superieure de J 1c
10 citations
TL;DR: The user requirements are essential in establishing the detection system performance specifications, engineering design goals, and in effective design trade-off management.
Abstract: A preliminary list of explosives vapor detection system user requirements is prescribed for three basic applications: (1) Processing—item and personnel examination at a processing station; (2) searching—area search and examination by portable, semiportable, and stationary systems; and (3) monitoring—enclosure atmosphere monitoring for explosive vapors. The user requirements common in relative importance to each application are examination or processing rate, maximum allowable false- and missed-alarm probability, and operator training level. For specific applications, the more important requirements are those related to weight, size, and power for area search, and unattended operation for enclosure monitoring applications. The user requirements are essential in establishing the detection system performance specifications, engineering design goals, and in effective design trade-off management.
TL;DR: A brief account is given of the principles of dual-energy computerized tomography (DECT) and of the potential which DECT has demonstrated for the automated detection of commercial and military explosives concealed in suitcases or packages.
Abstract: A brief account is given of the principles of dual-energy computerized tomography (DECT) and of the potential which DECT has demonstrated for the automated detection of commercial and military explosives concealed in suitcases or packages. A description of a breadboard system configured for this purpose is provided and recent advances in the state of the art in CT are discussed in the light of their potential significance for explosives detection.
TL;DR: In this article, the top-on ultrasonic method was applied to the rising load KIscc testing and the validity was confirmed by comparing the determined KIcc values with those measured according to the conventional KICC testing in the same environments.
Abstract: The Top-on ultrasonic method proposed earlier was applied to the rising load KIscc testing and the validity was confirmed by comparing the determined KIscc values with those measured according to the conventional longtime KIscc testing in the same environments. In addition, the influences of loading rate, fatigue precracking stress intensity level, and fracture morphology of fatigue precracked zone on KIscc were discussed.
TL;DR: In this paper, a ring-shaped clip-on displacement gage for fracture mechanics testing is described, which offers superior sensitivity and operating conveniences compared with the conventional double-cantilever beam type gage referenced in ASTM fracture test standards.
Abstract: A ring-shaped clip-on displacement gage for fracture mechanics testing is described. The novel design of this gage offers superior sensitivity and operating conveniences compared with the conventional double-cantilever beam type gage referenced in ASTM fracture test standards. The construction of ring gages for room temperature and cryogenic applications is discussed.
TL;DR: In this article, the authors discuss the most probable pore-size distribution, alternative meanings of average pore size, and how these measurements correlate with results of separate filtration tests.
Abstract: This paper discusses permeability (fluid flow) as a function of porosity (void volume) and average pore size, the most probable pore-size distribution, alternative meanings of average pore size, and how these measurements correlate with results of separate filtration tests.
TL;DR: In this article, the fracture toughness, sustained load flaw growth, and fatigue-crack propagation resistance of S200E hot-pressed beryllium at room temperature were investigated.
Abstract: This paper presents the results of an investigation into the fracture toughness, sustained-load flaw growth, and fatigue-crack propagation resistance of S200E hot-pressed beryllium at room temperature It also reviews the literature pertaining to the influence of various factors on the fracture toughness of hot-pressed beryllium determined using fatigue-cracked specimens
TL;DR: In this paper, the influence of various parameters on the spatial resolution and repeatability of the image is described. But, the authors do not consider the effect of the concentration of potassium iodide and starch on the performance of the analysis.
Abstract: The gel electrode method of detecting and imaging very small fatigue cracks in aluminum alloys provides the basis for a more rapid evaluation of fatigue performance and offers the convenience of periodic inspections during a test to monitor the initiation and growth of cracks. However, repetitive imaging of fatigue cracks can yield images with successively weaker contrast. This problem can be avoided by the correct selection of the operating parameters. This report describes the influence of various parameters on the spatial resolution and repeatability of the image. The spatial resolution is increased by increasing the starch concentration and reducing the charge flow. To obtain repeatable images the pulse duration (and charge) must be adjusted to balance the effects of the processes of passivation and corrosion. Sodium borate, which was previously included as an electrochemical buffer, should be omitted because it promotes too much passivation. Increasing the concentration of potassium iodide deters passivation so that images can be obtained repeatably with a shorter voltage pulse, less charge, and better spatial resolution. A compromise must be made between the spatial resolution and the visibility of the image. For routine inspection of components a highly visible image can be obtained with a gel electrode containing 0.06 M potassium iodide (KI) and 0.2 M starch upon application of a 10 V, 50 ms pulse. This combination yields repeatable images of cracks in aluminum alloys, with a spatial resolution ≈ 6 × 10−2 mm.
TL;DR: In this article, the sensitivity of traditional equations to various parameters and concludes that the edition of 1983 and the previous editions of ASTM Methods for Static Tests of Timbers in Structural Sizes (D 198) were not suitable for determination of shear modulus in structural lumber.
Abstract: Traditional equations for determining shear modulus for beams are based on several simplifying assumptions. Although these assumptions are reasonably accurate for isotropic homogenous beams, they can introduce large errors when applied to beams of structural lumber that are not isotropic or homogeneous. This paper examines the sensitivity of the traditional equations to various parameters and concludes that the edition of 1983 and the previous editions of ASTM Methods for Static Tests of Timbers in Structural Sizes (D 198) were not suitable for determination of shear modulus in structural lumber. An alternative test method currently used in Europe was proposed. Based on the considerations in this paper, this method was adopted in the 1984 edition of ASTM D 198.
TL;DR: In this paper, two-part analytic functions are used to approximate stress-strain curves for Kevlar-cloth reinforced epoxy composites, and the test records are automatically processed using regression analyses routines.
Abstract: Stress-strain curves for Kevlar-cloth reinforced epoxy composites have been approximated by two-part analytic functions. Autographic test records are digitized using a computer-assisted procedure, and the digitized data are automatically processed using regression analyses routines. Tensile data are best approximated by a bilinear function; compressive data are best fit to either a parabolic-linear or a parabolic-exponential function. The errors of fit of the analytic functions to the test data are smaller than the experimental errors of the test. One application of the technique is for economic computer storage of stress-strain curves. A maximum of four constants and a one-digit code number are all that are required to store an entire stress-strain curve. Also, average stress-strain curves can readily be obtained and various moduli are easily calculated.
TL;DR: In this paper, the authors evaluated the merits of spiral-stiffened polyvinyl chloride pipes over plain (unstiffed) pipes and concluded that considerable saving in material could be realized with no significant loss in pipe stiffness or impact resistance by adopting a spiral stiffened pipe design rather than a plain design.
Abstract: The evaluation of the merits of spirally stiffened polyvinyl chloride pipes over the merits of conventional plain (unstiffened) pipes is achieved experimentally. Various relevant standard tests have been performed on both types of pipes made of the same material. These tests are bursting, impact resistance and short- and long-term stiffness tests. The experimental results are compared favorably with appropriate formulae found in the literature. It is concluded that considerable saving in material could be realized with no significant loss in pipe stiffness or impact resistance by adopting a spirally stiffened pipe design rather than a plain design.
TL;DR: In this article, the bending stiffness and bending strength of three-stringer wood pallets used in drive-in racks are investigated. But the performance of these pallets is governed by the bending behavior of the deckboards as affected by the distribution of the load and the rigidity of the nailed joints.
Abstract: Wood pallets are increasingly being used in drive-in racks and are often positioned for easy access with supports parallel to the outer stringers. The performance of these pallets is governed by the bending behavior of the deckboards as affected by the distribution of the load and the rigidity of the nailed joints. This report gives design formulas for calculating the short-term constant environmental condition bending stiffness and bending strength of three-stringer pallets used in racks. The formulas treat an arbitrary rigidity of the nailed joints and an arbitrary area of the top deck covered by a uniformly distributed, symmetric, and centrally applied load.
TL;DR: In this article, a systematic attempt has been made to assess the influence of varying gage length, width, and thickness of rectangular tension specimens on the elongation values for American Iron and Steel Institute (AISI) Type 316 (Unified Numbering System [UNS] S31600) stainless steel.
Abstract: Different standards such as those of ASTM, Indian Standards Institution (IS), Association Francaise de Normalisation (AFNOR), British Standards Institution (BS), International Organization for Standardization (ISO), and Deutsche Industrie-Normen (DIN), specify different dimensions and relationships between gage length and cross-sectional area for the standard and proportional tension specimens of various geometries. In this investigation a systematic attempt has been made to assess the influence of varying gage length, width, and thickness of rectangular tension specimens on the elongation values for American Iron and Steel Institute (AISI) Type 316 (Unified Numbering System [UNS] S31600) stainless steel. The ratio of gage length to the square root of cross-sectional area is found to be an appropriate parameter for correlating total elongation with specimen dimensions. Conversion relationships have been obtained between total elongation and gage dimensions for 316 stainless steel.
TL;DR: In this paper, it was suggested that the arrested cleavage crack tip is a more potent flaw than the fatigue precrack, and the toughness values obtained using fatigue-precracked compact specimens are somewhat higher.
Abstract: Values of fracture toughness obtained by cleavage reinitition of arrested cleavage cracks in compact specimens are found to agree with those obtained from thermal shock experiments on much larger cylinders. In contrast, toughness values obtained using fatigue-precracked compact specimens are somewhat higher. It is suggested that the arrested cleavage crack tip is a more potent flaw than the fatigue precrack.
TL;DR: In this paper, a summary of JIc test procedures based on an ultrasonic method proposed earlier is presented, where the single-specimen JIC measurements for low and intermediate-strength, high-toughness materials show excellent agreement with those determined by multispeciment test procedures.
Abstract: This paper reports the summary of JIc test procedures based on an ultrasonic method proposed earlier. The single-specimen JIc measurements for low- and intermediate-strength, high-toughness materials show excellent agreement with those determined by multispeciment test procedures. The JIc values of the weldment were also determined from a single specimen. In addition, a statistical analysis of the JIc distribution was done.
TL;DR: In this article, a method is presented for approximating stress intensity factors for notched-configurations without cracks, which can be used in estimating the failure load in a notched structure behaving in an idealized elastic manner.
Abstract: A method is presented for approximating stress intensity factors for notched-configurations without cracks. It is expected that estimates obtained from such analyses, which are outlined in the text and detailed in the Appendix, should be useful in estimating the failure load in a notched structure behaving in an idealized elastic manner. Additionally, this approach will allow an estimate of the magnitude of load required to precrack fracture toughness specimens having crack starter notches. Several notch geometries and loadings are investigated, such as a V-notch, to first illustrate the method of analysis and compare results with those in the literature and to also establish merit and accuracy limits of the method. Two additional cases are then solved, both for finite width tensile sheets, one having symmetric U-notches and the other employing a central slot with finite radii at each end. Both cases are reduced to their end limit: a U-notch in a sheet of semi-infinite width and a circular hole in an infinitely wide sheet. The resulting approximations agree well with limited available data. Finally, to aid the experimentalist who either uses the compliance approach or a photoelastic analysis to obtain stress intensity factors, the question of how deep or how long a side-edge U-notch or a central slot compared to its radius should be to simulate a crack, is provided.
TL;DR: In this paper, five laboratories evaluated the effects of interlaboratory variability and bias in strain-cycle fatigue testing of 1.2mm-thick sheet specimens and found that the cyclic stress-strain curve is sensitive to the effects and bias of inter-labeling differences.
Abstract: Five laboratories undertook a study to assess interlaoratory variability and bias in strain-cycle fatigue testing of 1.2-mm-thick sheet specimens. In addition, one laboratory evaluated the effects of specimen geometry, actuator restraint, extensometer mounting surface, etc., on validity and bias of cyclic stress-strain and strain-life data. The results show that the cyclic stress-strain curve is sensitive to the effects of interlaboratory differences. The strain-life curve is also affected by results from different laboratories, but in addition it is sensitive to testing variables such as extensometer mounting surface, failure criterion, specimen, geometry, etc. The results of this study have implications for the development of a test method and for the use of strain-cycle fatigue data obtained from thin sheet specimens. The results reported here form a basis for expanding ASTM Recommended Practice for Constant-Amplitude Low-Cycle Fatigue Testing (E 606) to include materials with thicknesses less than 2.5 mm.
TL;DR: In this article, a new method has been developed for in situ compliance measurements on fatigue crack growth specimens, which is particularly well suited for autoclave testing where direct observation of the specimens is impossible.
Abstract: A new method has been developed for in situ compliance measurements on fatigue crack growth specimens Crack lengths may then be inferred from the compliance measurements The method is particularly well suited for autoclave testing where direct observation of the specimens is impossible The new method uses the change in induced eddy current fields with specimen loading as a measure of specimen compliance Calibration of the device in various environments and temperatures is discussed
TL;DR: In this article, a simple method for the measurement of biaxial deformation with a resolution of 0.025 μm (1 μin) was described, based on the use of an optical extensometer.
Abstract: A new and simple method is described for the measurement of biaxial deformation with a resolution of 0.025 μm (1 μin.). The basis for this technique is the use of an optical extensometer.
TL;DR: In this paper, high strain rate hot tension tests have been carried out on AISI 1020 (Unified Numbering System [UNS] G10200) steel using a Gleeble® testing machine.
Abstract: High strain rate hot tension tests have been carried out on AISI 1020 (Unified Numbering System [UNS] G10200) steel using a Gleeble® testing machine. Tests have been terminated at a series of strains and the specimen geometries measured. From these measurements, local areas, strains, and strain rates are derived and are used to obtain the local true stress-true strain curves. These are corrected for the change in strain rate with strain using an equation of state. The corrected curves are in good agreement with published curves on similar steels determined by compression or torsion testing. Under the present testing conditions, the maximum strain to which correction can be applied is ∼ 1.5. This is imposed by the onset of rapid local deformation heating. Up to this strain, no stress correction of the Bridgmann type for necking appears to be necessary.
TL;DR: Results indicated that very consistent and reproducible data can be obtained regardless of the method used, and a set of recommended procedures was appended to ASTM Test Method for Dynamic Tear Energy of Metallic Materials under the title, Determination of Percent Shear Fracture Appearance.
Abstract: ASTM Task Group E24.03.02 on Dynamic Tear Testing evaluated the various procedures used for determining the percent shear fracture surface appearance of dynamic tear (DT) test specimens. The entire gage range of standard DT specimens was investigated. The techniques used ranged from direct visual inspection of the fracture surface to various cleavage area measurement methods using fracture surface photographs. Results based on 35 DT specimens indicated that very consistent and reproducible data can be obtained regardless of the method used. In most cases, either the original or the final specimen cross section can be used as reference, the percent shear results differing by only 5 to 10% between the two areas. Careful visual rating by a trained individual can give results very similar to the more time-consuming methods and is acceptable in most cases. Based on these results a set of recommended procedures was appended to ASTM Test Method for Dynamic Tear Energy of Metallic Materials (E 604) under the title, Determination of Percent Shear Fracture Appearance.