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*Stress/Strain Direct |
 
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*Stress/Strain Direct
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*Stress/Strain Direct |
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To define direct stress-strain curves for non-linear materials.
Refer to Non-Linear Elastic materials for further information on this feature.
A block of lines that defines a stress-strain curve, repeated as often as necessary. The block begins with a line defining the curve name. It is followed by as many lines as necessary to define each point on the curve.
Line defining the curve name:
CURVE=Curve Name
Line defining a point on a curve:
Direct Stress, Direct Strain
Each curve must have at least two points defined. This type of stress-strain curve may not be associated with non-linear beam elements which are defined using the rigid riser format for geometric properties specification.
Input: |
Description |
Curve Name: |
The generic name of the direct stress-strain curve. |
Stress: |
A direct stress value for a point on the curve. |
Strain: |
The corresponding direct strain value. |
(a)This table is used to define direct stress-strain curves that define E for a particular set of elements. Direct stress-strain curves may be assigned to element sets using the Rigid Riser Format table.
(b)Use as many lines as you need to completely define a particular stress-strain curve. Simply leave Column 1 blank for second and subsequent lines. For subsequent stress-strain curves, put the curve name in Column 1 and specify the stress-strain data in the same way.
(c)The points defining the non-linear stress-strain curve may be specified in any order. Flexcom subsequently sorts the data pairs into ascending order of strain.
(d)If the strain in an element lies between the specified stress-strain data points, Flexcom uses linear interpolation to determine the relevant stiffness of the element.
(e)If the strain in the element lies outside the specified range of the stress-strain curve, then Flexcom simply extrapolates from the first or last section of the curve as appropriate.
(f)If none of the specified strain terms have a negative value, the curve is assumed to be symmetrical about the origin (i.e. the behaviour of the element is the same for both positive and negative strains)