abaqus的材料参数

Department of Engineering University of Cambridge > Engineering Department > computing helpABAQUS Materials Input1. 5. ABAQUS - Materials

2. Q5.1 : How do I find what material properties are needed for a particular analysis ?

Read the relevant section in Chapter 6 : Analysis Procedures (User's manual Vol. I). This gives an overview about theanalysis and has more information about the material properties.

Read also the following sections in Chapter 17 : Materials Introduction of the ABAQUS User's manual.Section 17.1.1 - Material Library : OverviewSection 17.1.2 - Material Data DefinitionSection 17.1.3 - Combining Material Properties

Section 17.1.3 lists the material model combination tables. Several models are available to define the mechanical behaviour(elastic, plastic).

Some material options require the presence of other material options. Some exclude the use of the other material options.For example *DEFORMATION PLASTICITY completely defines the material's mechanical behaviour and should not beused with *ELASTIC.

Once you have all the relevant keywords to define the material properties consult the keyword Manual for each of thekeywords. This will explain what data is required for each of the keyword.

3. Q5.2 : What material properties need to be specified in a thermal-electrical analysis ?

Referring to Section 17.1.3 of the ABAQUS User's manual you will require the heat transfer properties as well as theelectrical properties. These are listed below :Heat Transfer properties*CONDUCTIVITY*LATENT HEAT*SPECIFIC HEAT*HEAT GENERATIONElectrical properties*DIELECTRIC

*ELECTRICAL CONDUCTIVITY*JOULE HEAT FRACTION*PIEZOELECTRIC

This forms the complete set of properties. If Piezoelectric elements are not used then*PIEZOELECTRIC and *DIELECTRIC properties will not be required.

If only the steady state heat transfer response is of interest then *SPECIFIC HEAT properties are not required. Similarly ifthere are no phase changes involved then *LATENT HEAT is not required.

*JOULE HEAT FRACTION is used to specify the fraction of electrical energy that will be released as heat.

Example problem 5.2.1 - thermal-electrical modelling of an automotive fuse illustrates the thermal-electrical analysis.ABAQUS allows for redundant material properties to be specified. It will simply ignore the material properties not required forthe current analysis.

Typical example of material properties :*MATERIAL, NAME=ZINC*CONDUCTIVITY0.1121, 20.00.1103, 100.0

*ELECTRICAL CONDUCTIVITY16.75E3, 20.012.92E3, 100.0

*JOULE HEAT FRACTION1.0*DENSITY7.14E-6

*SPECIFIC HEAT389.04. Q

5.3 : What material properties need to be specified in an analysis using temperature- displacement elements ?Referring to Section 17.1.3 of the ABAQUS User's manual you will require the heat transfer properties as well as themechanical properties. These are listed below :Mechanical properties*ELASTIC

Additional properties which may be required : example plastic Heat Transfer properties*CONDUCTIVITY*LATENT HEAT*SPECIFIC HEAT*HEAT GENERATION

5. Q5.4 : What material properties need to be specified in an analysis using piezoelectric elements?

Referring to Section 9.1.3 of the ABAQUS User's manual you will require the electrical properties. These are listed below :Electrical properties*DIELECTRIC

*ELECTRICAL CONDUCTIVITY*JOULE HEAT FRACTION

*PIEZOELECTRIC

6. Q5.5 : What material properties need to be specified in modeling concrete with reinforcements?Use the concrete model available with rebar to model the reinforcements.

Section 1.1.5 of the ABAQUS Example's manual gives an example of the collapse analysis of a concrete slab subjected to acentral point load.

The data file for that example is collapse example.

The complete set of ABAQUS input files can be obtained by using the following command :abaqus fetch j=collapseconcslab**CONCRETE

3000., 0. abs. value of compressive stress, abs. value of plastic strain. 5500., 0.0015 \" \"*FAILURE RATIOS1.16, 0.0836

This is used to define the shape of the failure surface (see section 11.5.1 of the ABAQUSUSER's manual Vol. II).

The first parameter is the ratio of the ultimate biaxial compression stress, to the uniaxial compressive stress. Default is 1.16.The second parameter is the absolute value of the ratio of uniaxial tensile stress at failure to the uniaxial compressive stressat failure. Default is 0.09.7. Tension Stiffening*TENSION STIFFENING1., 0.0., 2.E-3

First parameter is the fraction of remaining stress to stress at cracking. The second parameter is the absolute value of thedirect strain minus the direct strain at cracking.

This defines the retained tensile stress normal to the crack as a function of the deformation in the direction of the normal tothe crack.

8. Shear Retention*SHEAR RETENTIONNot used for this example.9. Reinforcement modelling

*REBAR is used to model the reinforcement.

*REBAR,ELEMENT=SHELL,MATERIAL=SLABMT,GEOMETRY=ISOPARAMETRIC,NAME=YYSLAB, 0.014875, 1., -0.435, 4

*REBAR,ELEMENT=SHELL,MATERIAL=SLABMT,GEOMETRY=ISOPARAMETRIC,NAME=XXSLAB, 0.014875, 1., -0.435, 1

Here SLAB is the element name or name of the element set that contains these rebars. The geometry is ISOPARAMETRIC.Other choice is SKEW. ELEMENT can be BEAM, SHELL, AXISHELL or CONTINUUM type. The following are the otherparameters specified :

cross-sectional area of the rebar.

spacing of the rebars in the plane of the shell

position of the rebar. Distance from the reference surface. Here the mid-surface is the reference surface and the minus signindicates that the distance is measured in the

opposite direction to the direction of positive normal. The positive normal is defined by the right hand rule as the nodes areconsidered in an anti-clockwise sequence.edge number to which rebars are similar.

10. Alternate Method o modelling REBAR ReinforcementsAlternatively REBAR can be modelled as follows :*NODE........

**-------------------END NODES FOR REBAR BEAM ELEMENTS501, 0.0, 0.15, -0.02541, 1.5, 0.15, -0.02601, 0.0, 0.15, -0.07641, 1.5, 0.15, -0.07701, 0.0, 0.60, -0.02741, 1.5, 0.60, -0.02801, 0.0, 0.60, -0.07841, 1.5, 0.60, -0.07........

**---------------------GENERATE INTERMEDIATE NODES*NGEN, NSET=BAR10TF701, 741, 2

*NGEN, NSET=BAR10TB801, 841, 2......

**--------------------GENERATE THE BEAM ELEMENTS*ELEMENT, TYPE=B31701, 701, 703801, 801, 803

*ELGEN, ELSET=BAR10TF701, 20, 2, 1, 1, 1, 1

*ELGEN, ELSET=BAR10TB

801, 20, 2, 1, 1, 1, 1......

**---------------------DEFINE THE MATERIAL PROPERTIES*MATERIAL, NAME=BAR8**

** 8 mm dia bar**

*ELASTIC, TYPE=ISO197.E6, 0.3*PLASTIC354.E3, 0.364.E3, 0.0018**

**---------------------DEFINE THE SECTION PROPERTIES......

*BEAM SECTION, SECTION=CIRC, MATERIAL=BAR10, ELSET=BAR10TF0.005

*BEAM SECTION, SECTION=CIRC, MATERIAL=BAR10, ELSET=BAR10TB0.005...

**--------------------DEFINE AN ELEMENT SET WHICH CONTAINS**--------------------THE ELEMENTS THROUGH WHICH THE REBAR**--------------------ELEMENTS PASSES.....

*ELSET, ELSET=TOP, GENERATE5, 80, 5**

**--------------------*EMBEDDED ELEMENT,HOST ELSET=TOPBAR10TF,BAR10TB**

11. Q5.6 : What material properties need to be specified in using the deformation plasticity model ?

See section 11.2.11 of the users' manual (Vol. II). See also section 23.4.7 of the users' manual (Vol. III), keyword section.

For example :

*DEFORMATION PLASTICITY1.E3, 0.3,2., 3, 0.396

Here the data line contains the Young's modulus, Poissons ratio, Yield stress, Exponent, Yield offset respectively. If it isnecessary to define the dependence of these parameters on temperature then the 6th parameter will be the temperature.Then repeat the dataline for different temperatures as required.| Computing Help |[Finite Elements] | [Engineering Packages] Cambridge University Engineering DeptInformation provided by Arul M Britto (amb2)Last updated: 28 September 2010