Users:General FEM Analysis/Elements Reference/SolidTetra1

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−	=== Parameters of Element Property Block ===	+	== Input Parameters ==
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		+	=== Parameter Description ===
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	EL-PROP 1: SOLIDTETRA1		EL-PROP 1: SOLIDTETRA1

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Revision as of 07:59, 2 September 2010

Contents 1 General Description 1.1 Element Type 1.2 Degrees of Freedom 2 Input Parameters 2.1 Parameter Description 2.2 Example of a Complete Input Block 3 Element Loading 3.1 Dead Load 3.2 Temperature Load 4 References

General Description

Element Type

• This element class provides 3D tetrahedal elements with linear (4-noded element) or quadratic shape functions (10-noded)

Degrees of Freedom

All tetrahedal elements use three translatoric degrees of freedom at each node.
They are named Disp_X, Disp_Y, Disp_Z.

Input Parameters

Parameter Description

Compulsory Parameters
Parameter	Values, Default(*)	Description
MAT	EL-MAT int	Linking to a material input block
INT_TYPE_TETRA	FULL	Control of integration type Only full inetgration available so far
Optional Parameters

Example of a Complete Input Block

EL-PROP 1: SOLIDTETRA1
MAT           = EL-MAT 1
INT_TYPE_TETRA = FULL

Inside the property block there is no distinction between linear and quadratic formulated elements. It is possible to define 4-noded and 10-noded elements using one and the same element property:

 !  ElementID  Part-ID       EL-PROP             Node-IDs
NEL  1           1             1            1  2  3  4                                    ! 8-noded element
NEL  2           1             1            20 21 22 23 24 25 26 27 28 29                 !10-noded element

Element Loading

Tetrahedal elements are able to carry two types of element loads:

• dead load
• temperature load

Dead Load

Dead weight of an element is computed by multiplying material's denisity (ρ) with gravity's acceleration, which has to be defined inside the load block concearning its direction and size.
An example for a load definition of a concrete structure (assuming linear elastic isotropic material behaviour) with gravity acting in positive z-direction would look like

EL-MAT 1 : LIN_ELAST_ISOTROPIC
EMOD=3.5e10  ALPHAT=1e-5  DENS=2.5e3  NUE=0.2

LD-ELEM 1 PART=1 
 TYPE=DEAD      D1=0.0   D2=0.0   D3=1.0  VAL=9.81

whereat the finite elemet model is based on SI units (m, N, kg).

Temperature Load

This paragraph only focuses at element specific topics concearing temperature load. For more detailed descriptions please look at the load documentation

For the computation of temperature loads solid elements do not concider any layer of laminate structure within the element. So only the temperature defined for layer number one is considered at each node.

LD-ELEM 1  
 TYPE = TEMPERATURE
 ND-SET = 1  LAYER = 1  VAL = +10
 ND-SET = 2  LAYER = 1  VAL = -10

References

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