Design and Testing
Composites test method globalization and harmonization
In my previous column, I discussed the need for standardization of test methods and the progress that has been made in recent years (see “Related Content,” at left). However, we know from that column, and many preceding it, that when we attempt to determine material properties, there is often more than one
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Why standardize composites test protocols?
Every column I write for HPC eventually refers to “standard” test methods. But why are standards written? What groups promote these standards, and who actually writes them? Most importantly, why do the rest of us need to follow their standards, and what if we don’t? To answer the first question, we must step back into
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Testing Tech: Adhesion testing of sandwich panels
In my three preceding columns, I discussed the testing of sandwich panels as unit structures. This included flexural and shear testing of beams and panels. However, such tests — and hardware components that are designed accordingly — will not produce the desired results unless the adhesives that hold these panels
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Testing Tech: Shear testing of sandwich panel core materials
In my previous column (HPC November 2006, p. 10), I noted that the shear strength and shear stiffness of the core material in a sandwich panel can be determined in situ while performing flexural tests to evaluate other sandwich panel properties. However, as was stated then, it is more accurate to measure these
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Sandwich panel flexure testing
Dr. Donald F. Adams (Wyoming Test Fixtures (Salt Lake City, Utah) comments on the composite materials testing community's move toward the use of the terms "long beam flexure" and "short beam flexure" when addressing sandwich panel testing.
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Sandwich panel test methods
This column will introduce sandwich panel test methods in general. Detailed discussions of the individual test methods will be presented in future columns. Sandwich panels will be defined here as those consisting of relatively thin facesheets that are strong and stiff in tension and compression compared to the low
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Back-out factors
Dr. Adam's follows up a previous column, in which he discussed the advantages of testing a cross-ply laminate and then "backing out" the unidirectional composite strength, with an expanded examination of back-out factors that can be applied to other types of laminates.
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Testing cross-ply vs. unidirectional composites
Dr. Don Adams follows up his previous column on tensile testing with a discussion of such testing when confronted by two difficult-to-test laminate configurations.
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Unidirectional composite axial tensile specimens
Dr. Don Adams explains why the design of tensile test coupons is more art than science, and explains the implications of that art for testing accuracy.
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Flexure test methods
The three fundamental mechanical property characterization tests of materials are tension, compression and shear. Note that flexure is not included. This article addresses some of the reasons why. When a beam resting on supports near its ends is loaded, the supported side is in tension and the opposite side is in
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