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OS-C501

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Offshore Standard DNV-<strong>OS</strong>-<strong>C501</strong>, November 2013<br />

App.C Test methods for laminates – Page 218<br />

Guidance note:<br />

This method is similar to the digestion method, except that the matrix is removed by the burning. This method works<br />

well for glass fibre reinforced composites. In calculating the volume fraction it is important to distinguish between<br />

fibre volume fraction and fibre weight fraction.<br />

C.5 Tests on tubular specimens<br />

C.5.1<br />

---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---<br />

C.5.1.1 For tubular components it is often preferable to test the laminate properties also on tubular specimens.<br />

C.5.1.2 Recommended test methods are ASTM D 5448, ASTM D 5449 and ASTM D 5450.<br />

C.6 Evaluation of stress versus strain curves<br />

C.6.1 Brittle characteristics<br />

C.6.1.1 A typical schematic of a stress-strain curve for a brittle material is shown in Figure C-1. The following<br />

elastic parameters are shown: elastic modulus for the linear range (E or G for shear), strength and strain at<br />

failure point (σ ult and ε ult ). Note that the linear limit (σ lin and ε lin ) is here the same as the point of failure.<br />

σ<br />

ult lin<br />

failure point<br />

Stress<br />

E lin<br />

Strain<br />

ε<br />

ult lin<br />

: Stress-strain relation<br />

Figure C-1<br />

Properties to be measured on a linear stress-strain curve for a brittle core materials<br />

C.6.1.2 Calculation of modulus of elasticity:<br />

where i represents the index for the linear limit or ultimate value, etc.<br />

C.6.2 Plastic characteristics<br />

σ<br />

E<br />

i<br />

=<br />

ε<br />

C.6.2.1 A typical schematic of a stress-strain curve for a plastic material is shown in Figure C-2. The following<br />

elastic parameters are shown: elastic modulus for the linear range and non-linear range (E or G for shear),<br />

strength and strain at failure point (σ ult and ε ult ), strength and strain at yield point (σ yield and ε yield ).<br />

i<br />

i<br />

DET NORSKE VERITAS AS

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