Mechanical APDL Structural Analysis Guide

The following input listing is an example showing the linear unloading behavior of a gasket joint ma-
terial with 3 unloading points

TB,GASKET,1, ,3,LUNL! define linear unloading data

TBPT,, 0.78000E-04, 0.25100E+12

TBPT,, 0.28600E-03, 0.25500E+12

TBPT,, 0.50500E-03, 0.10600E+13

A sample plot representing linear unloading curves is shown in Figure 10.3: Gasket Material Input: Linear
Unloading Curves (p. 323).

Figure 10.3: Gasket Material Input: Linear Unloading Curves

10.4.2.4. Define Nonlinear Unloading Data

(TBOPT = NUNL)

The nonlinear unloading gasket material definition option provides a more comprehensive way of de-
fining gasket material unloading behavior. The input listing format is:

TB,GASKET,MAT,NTEMP,NPTS,NUNL

TBPT,,x1,y1

TBPT,,x2,y2

TBPT,,xi,yi

where: xi, yi are pairs of closure and pressure values. Several unloading curves can be defined.

An example showing the nonlinear unloading behavior of a gasket joint material with 3 unloading
points is as follows:

TB,GASKET,1, ,5,NUNL! define first nonlinear unloading data

TBPT,, 0.78000E-04, 0.30000E+09

TBPT,, 0.66900E-04, 0.24750E+08

TBPT,, 0.63100E-04, 0.82500E+07

TBPT,, 0.54100E-04, 0.15000E+07

TBPT,, 0.00000E+00, 0.00000E+00

TB,GASKET,1, ,5,NUNL! define second nonlinear unloading data

TBPT,, 0.28600E-03, 0.58500E+09

TBPT,, 0.26400E-03, 0.22350E+08

TBPT,, 0.26100E-03, 0.90000E+07

TBPT,, 0.25600E-03, 0.15000E+07

TBPT,, 0.00000E+00, 0.00000E+00

TB,GASKET,1, ,5,NUNL! define third nonlinear unloading data

TBPT,, 0.50500E-03, 0.89550E+09

TBPT,, 0.47800E-03, 0.33900E+08

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Material Definition