scholarly journals Comparing Test Methods for the Intra-ply Shear Properties of Uncured Prepreg Tapes

2020 ◽  
Vol 27 (1) ◽  
pp. 89-96
Author(s):  
Klaus Heller ◽  
Moritz Hallmannseder ◽  
David Colin ◽  
Kalle Kind ◽  
Klaus Drechsler
Keyword(s):  
Material Properties ◽  
Deformation Behavior ◽  
Standardized Test ◽  
Test Methods ◽  
Test Method ◽  
Test Procedures ◽  
Automated Fiber Placement ◽  
Bar Test ◽  
Torsion Bar ◽  
Rheometer Test

AbstractTo achieve cost-efficient manufacturing and a high part quality in Thermoset Automated Fiber Placement (TS-AFP), knowledge about the interaction between material and process parameters is of special interest. Material properties of prepregs are well known at the cured state of the resin. However, there are no standardized test procedures for the mechanical behavior of the uncured prepreg tapes. To investigate the intra-ply shear deformation behavior of uncured unidirectional prepreg tapes, we compared several measurement procedures and conducted experiments for rheometer based tests using 8552/AS4 material. We identified a rotational parallel platens rheometer test method and a torsion bar rheometer test method to be suitable. Experiments using both methods revealed that the Torsion Bar Test has a higher repeatability and the analysis is less complex. Furthermore, first results show that changes in material properties caused by aging can be analyzed using this method. In the future,we will use the Torsion Bar Test to characterize changes in deformation behavior due to material aging as well as material modifications. By this, we will be able to provide data for the material modeling thus enabling the prediction of lay-up defects such as buckling due to steering.

Standardized Test Methods for Use in Waste Compliance Testing in the Department of Energy'S Waste Acceptance Process

1986 ◽  
Vol 84 ◽  
Author(s):  
George B. Mellinger
Keyword(s):  
Standardized Tests ◽  
Standardized Test ◽  
Test Methods ◽  
Test Method ◽  
Approval Process ◽  
Test Procedures ◽  
Compliance Testing ◽  
American Society

Summary:Standardized test methods that are currently in use or under development appear to adequately cover most of the testing that may be required to demonstrate compliance with the WAPS. It may be important to complete standardization of those tests that are under development, and to develop additional standardized tests for those specifications for which no standardized tests exist. A significant amount of work would be involved in this effort. Therefore, before this effort is undertaken, DOE must decide whether there is a need for a set of standardized test methods that would receive an “official approval” for use in waste compliance testing. If a set of approved tests is needed, DOE would need to determine what types of tests to include in the “approved list”, who should develop these tests, and which organizations should review and approve the test methods. Test method review and approval might be accomplished through the use of the Materials Review Board (MRB), an organization that was created by DOE for the purpose of reviewing and approving key test methods and data related to the repository licensing process. Alternatively, other means of standardizing these tests might be considered, such as processing the tests through the American Society for Testing and Materials for publication as ASTM standards.If a set of approved tests is adopted, producers would not be required to use these tests; however, if a producer wished to propose other tests for compliance testing, it would be reasonable to require that such test procedures undergo a review/approval process similar to that which the officially approved tests had undergone. Once approved, these alternate procedures could be used for compliance testing.

Review of material test standardization status for the material qualification of laminated thermosetting composite structures

2020 ◽  
pp. 073168442095810
Author(s):  
Sang Yoon Park ◽  
Won Jong Choi
Keyword(s):  
Composite Materials ◽  
Material Properties ◽  
Composite Structures ◽  
Failure Modes ◽  
Laminated Composite ◽  
Test Methods ◽  
Test Method ◽  
Experimental Comparison ◽  
Laminated Composite Materials ◽  
Design Values

This paper presents a review of recent literature related to the static mechanical testing of thermoset-based carbon fiber reinforced composites and introduces a material qualification methodology to generate statistically-based allowable design values for aerospace application. Although most test methods have been found to be effective in determining the specific material properties by incorporating them into the material qualification and quality control provisions, a full validation to clarify the behavior of thermoset-based laminated composite materials is currently lacking, particularly with regard to the characterization of compressive, in-plane, interlaminar shear, and damage tolerance properties. The present study obtains information on the different types of test method that can be employed within the same material properties, and makes an in-depth experimental comparison based on the past literatures. A discussion on the scope of theoretical analysis involves a description of how the proposed test method can be adequate for obtaining more accurate material properties. This discussion is directly applicable to the assessment of material nonlinearity and the geometrical effect of specimens. Finally, the resulting failure modes and the effect of each material property are studied to aid the understanding of the load distribution and behavior of laminated composite materials.

Reliability of Miniature Concrete Prism Test in Assessing Alkali-Silica Reactivity of Moderately Reactive Aggregates

2020 ◽  
Vol 2674 (4) ◽  
pp. 23-29
Author(s):  
Harish Konduru ◽  
Prasad Rangaraju ◽  
Omar Amer
Keyword(s):  
False Positive ◽  
Standardized Test ◽  
False Negative ◽  
Test Method ◽  
Test Procedures ◽  
Concrete Prism ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Mortar Bar ◽  
Concrete Prism Test

Alkali-silica reaction (ASR) is one of the most significant durability issues in concrete structures. Although there are a number of standardized test procedures to evaluate the aggregate reactivity, each method has its own drawbacks. Two of the most common tests that are employed widely are the accelerated mortar bar test (AMBT) (ASTM C1260) and the concrete prism test (CPT) (ASTM C1293). The major issue with the AMBT test is the number of false-positive results from this test associated with high test temperature, rendering the test method unreliable. CPT is one of the most reliable tests for assessing the potential for ASR, but its major disadvantage is the duration of the test involved, which takes one to two years. In this research, a novel test method called the miniature concrete prism test (MCPT) was developed and the effectiveness and reliability of the results assessed when compared with CPT and AMBT. Samples of 26 coarse aggregates and 16 fine aggregates with various reactivity levels were employed for the testing. The test results were compared for MCPT versus CPT, in which 23 out of 26 coarse aggregates and eight out of 16 fine aggregates either passed or failed in both MCPT and CPT. For MCPT versus AMBT, 16 out of 26 coarse aggregates and 13 out of 16 fine aggregates either passed or failed in both MCPT and AMBT. The sensitivity of false-negative and false-positive aggregate sources is discussed and explained briefly.

Methods to Evaluate Cleaners and Sanitizers

1982 ◽  
Vol 45 (13) ◽  
pp. 1257-1260 ◽  
Author(s):  
DALE L. SCHEUSNER
Keyword(s):  
Test Methods ◽  
Test Method ◽  
Test Results ◽  
Standard Laboratory ◽  
Test Procedures ◽  
Laboratory Methods ◽  
Product Use ◽  
Cellulose Sponge ◽  
Equivalent Test ◽  
Recovery Methods

Methods to evaluate germicides can be grouped into three categories: standard laboratory tests, in-use tests and simulated-use tests. Standard laboratory methods, such as the Available Chlorine Germicidal Equivalent test, are specifically defined for reproducibility in any laboratory by any operator, but the test results often lack relevance to actual product-use conditions. In-use test methods are relevant to product-use; however, in-use test procedures do not permit proper controls to be included in the organism recovery methods. Contact plates give an estimate of organism numbers which is only 25% of the theoretical number of organisms present. Organism recovery using a swab, cellulose sponge or tube sampler give estimates of organisms ranging from 91 to 111% of theoretical. The tube sampler is a 1-in. length of flexible tubing having a 1-in. interior diameter and a smooth end, which can make a water-tight seal on a flat surface. Simulated use testing yields data which are relevant to actual product-use. A cafeteria tray is soiled, inoculated and cleaned in a manner to simulate actual product-use. This test method permits the necessary controls to be used. Tray-test reproducibility is as good as that of the other recovery methods tested and organism recovery is quantitative. The tray test provides a means for determining biological cleaning where the effect of both cleaning and germicidal activity are measured together.

scholarly journals Improvised Long Test Lengths via Stitching Scale Bar Method:

2020 ◽  
Vol 125 ◽  
Author(s):  
Shendong Shi ◽  
Bala Muralikrishnan ◽  
Vincent Lee ◽  
Daniel Sawyer ◽  
Octavio Icasio-Hernández
Keyword(s):  
Environmental Changes ◽  
Standardized Test ◽  
Critical Issue ◽  
Test Method ◽  
Maximum Deviation ◽  
Test Procedures ◽  
Short Scale ◽  
Reference Length ◽  
Order Of Magnitude ◽  
Point To Point

Periodic performance evaluation is a critical issue for ensuring the reliability of data from terrestrial laser scanners (TLSs). With the recent introduction of the ASTM E3125-17 standard, there now exist standardized test procedures for this purpose. Point-to-point length measurement is one test method described in that documentary standard. This test is typically performed using a long scale bar (typically 2 m or longer) with spherical targets mounted on both ends. Long scale bars can become unwieldy and vary in length due to gravity loading, fixture forces, and environmental changes. In this paper, we propose a stitching scale bar (SSB) method in which a short scale bar (approximately 1 m or smaller) can provide a spatial length reference several times its length. The clear advantages of a short scale bar are that it can be calibrated in a laboratory and has potential long-term stability. An essential requirement when stitching a short scale bar is that the systematic errors in TLSs do not change significantly over short distances. We describe this requirement in this paper from both theoretical and experimental perspectives. Based on this SSB method, we evaluate the performance of a TLS according to the ASTM E3125-17 standard by stitching a 1.15 m scale bar to form a 2.3 m reference length. For comparison, a single 2.3 m scale bar is also employed for direct measurements without stitching. Experimental results show a maximum deviation of 0.072 mm in length errors between the two approaches, which is an order of magnitude smaller than typical accuracy specifications for TLSs.

scholarly journals Literature Survey of Gaseous Hydrogen Effects on the Mechanical Properties of Carbon and Low Alloy Steels

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
P. S. Lam ◽  
R. L. Sindelar ◽  
A. J. Duncan ◽  
T. M. Adams
Keyword(s):  
Mechanical Properties ◽  
Structural Integrity ◽  
Standardized Test ◽  
Uniform Elongation ◽  
Test Methods ◽  
Hydrogen Gas ◽  
Test Method ◽  
Specimen Preparation ◽  
Low Alloy Steels ◽  
Alloy Steels

A compendium of mechanical properties of carbon and low alloy steels following hydrogen exposure has been assembled from literature sources. The property sets include yield strength, ultimate tensile strength, uniform elongation, reduction in area, threshold stress intensity factor, fracture toughness, and fatigue crack growth. These properties are from literature sources under a variety of test methods and conditions. The collection of literature data is by no means complete, but the diversity of data and dependency of results on test method are sufficient to warrant a design and implementation of a standardized test program. The program would be needed to enable a defensible demonstration of structural integrity of a pressurized hydrogen system. It is essential that the environmental variables be well-defined (e.g., the applicable hydrogen gas pressure range and the test strain rate) and the specimen preparation be realistically consistent (such as the techniques to charge hydrogen and to maintain the hydrogen concentration in the specimens).

scholarly journals Statistical method for the determination of equivalence of automated test procedures

2003 ◽  
Vol 25 (6) ◽  
pp. 123-127 ◽  
Author(s):  
K. Rick Lung ◽  
Mary A. Gorko ◽  
Jennifer Llewelyn ◽  
Norman Wiggins
Keyword(s):  
Test Methods ◽  
Test Method ◽  
Content Uniformity ◽  
Solid Dosage Forms ◽  
Test Procedures ◽  
Solid Dosage ◽  
Automated Test ◽  
Student’S T ◽  
Manual Test

In the development of test methods for solid dosage forms, manual test procedures for assay and content uniformity often precede the development of automated test procedures. Since the mode of extraction for automated test methods is often slightly different from that of the manual test method, additional validation of an automated test method is usually required. In addition to compliance with validation guidelines, developers of automated test methods are often asked to demonstrate equivalence between the manual and automated test methods. There are problems associated with using the traditional zero-difference hypothesis tests (such as the Student's t-test) for demonstrating equivalence. The use of the Westlake Interval and Schuirmann's Two One-sided test as more rigorous methods of demonstrating equivalence is discussed.

Inferring Viscoelastomer Dynamic Material Properties From Finite Element and Experimental Studies of Constrained Layer Damping Systems

2004 ◽  
Author(s):  
Stephen A. Hambric ◽  
Andrew W. Jarrett ◽  
Gilbert F. Lee ◽  
Jeffry J. Fedderly
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Standardized Test ◽  
Experimental Studies ◽  
Test Methods ◽  
Constrained Layer Damping ◽  
Resonance Frequencies ◽  
Different Temperatures ◽  
Dynamic Material Properties ◽  
Loss Factors

Viscoelastic materials are often used to add damping to metal structures, usually via the constrained layer damping method. The added damping is strongly dependent on material temperature and frequency, as are the underlying material properties of the viscoelastomer. Several standardized test methods are available to characterize the dynamic material properties of viscoelastomers. However, they rely on limited test data which is extrapolated using the time-temperature superposition technique. The authors have found that the different testing methods typically produce significantly different material properties. A new approach to inferring viscoelastomer material properties is suggested here. Several metal bars are treated using constrained layer damping. Experimental modal analyses are conducted on the bars at different temperatures to produce sets of system resonance frequencies and loss factors. Corresponding finite element (FE) models of the treated bars are analyzed using assumed viscoelastomer material properties. The properties are adjusted by trial and error until the FE-simulated system loss factors match those of the measurements.

A Fatigue Test to Assess the Deformation Behavior of Dental Implants

2010 ◽  
Author(s):  
Choongryeong Lee ◽  
Hyun-Yong Jeong
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Fatigue Life ◽  
Dental Implants ◽  
Fatigue Test ◽  
Material Properties ◽  
Deformation Behavior ◽  
Fatigue Tests ◽  
Test Method ◽  
Test Results

A purpose of this paper is to analyze the effects of material properties and design of a jig on fatigue test results of dental implants. An implant fatigue test method is specified in ISO14801 [1], but it is not described well about the fatigue test jig. The jig of ISO14801 has to firmly hold the fixture, and the elastic modulus of the jig should be more than 3 GPa. These requirements are not sufficient enough to represent the dental implant in the jawbone because the fixture is osseointegrated in the jawbone that is made up with the cortical bone and cancellous bone. In this paper three different materials were used for the jig, and two different fixation methods to hold the fixture were examined in several FE (Finite Element) simulations and fatigue tests. From the simulation and test results, the effects of material properties and design of the jig were evaluated in the light of fatigue life of dental implants.

Particle Emissions from Gas Handling Components Measured According to the SEMATECH Test Methods

1995 ◽  
Vol 38 (1) ◽  
pp. 29-33
Author(s):  
R. Periasamy ◽  
D. Ensor ◽  
A. Clayton ◽  
R. Donovan ◽  
J. Riddle
Keyword(s):  
Condensation Nucleus ◽  
Counting Efficiency ◽  
Test Methods ◽  
Test Method ◽  
Emission Rates ◽  
Test Procedures ◽  
Point Of Use ◽  
Ultra High Purity ◽  
Total Particle ◽  
Test Component

Particle emission rates measured from ultra-high purity, cleanroom gas handling components following the test procedures specified in the SEMATECH test methods are described. A condensation nucleus particle counter (CNC) having a counting efficiency of 50 percent at 0.02 μm in diameter was used to measure the total particle contribution from the gas handling components. A spool piece was inserted to measure the baseline particle concentration of the test stand before the measurement of the test component was carried out. Eighteen test samples, six each from three suppliers (two domestic and one foreign), in each type of gas handling components (valves, point-of-use filters, pressure regulators), were tested using the revised test method. Particle contribution data obtained for fresh out-of-the-bag, stainless steel (SS) test samples, 1/4-in. in OD, from different manufacturers are summarized in this paper.

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