Supports - Preventive Biomechanics - page 173

Fig. 4.27 a Test scenario of the indenter compression test employing the pre-tensioned fabric
material with rim and without leather cover, b and c simulated indenter positions
Fig. 4.28 Force-displacement data of indenter compression test employing the airplane seat with
pre-tensioned fabric lining and leather cover for a indenter position 1 and b indenter position 2
approximation employing an orthotropic H OOKE -model to characterize the lining
material (note the nearly linear corridor of the equilibrium elasticity) for plane
stress according to ( 3.294 ) , Figs. 4.26 a and 4.26 b. The Poisson ratio m 12 was
determined via separate tensile tests with a reflected-light microscope.
Figure 4.26 c depicts the resulting force-displacement data from hemispherical
punch testing of the cover material (Fig. 4.25 c) compared to the simulation fit data
based on the material model for equilibrium elasticity ( 3.274 ) .
For verification of the FE-seat model with the plain fabric material under pre-
tension attached to the rim without leather cover material and based on the pre-
viously derived material parameters two loading scenarios were conducted.
Hemispherical punch tests were performed, Fig. 4.27 a, at two different positions as
illustrated in Figs. 4.27 b and c and indenter force and displacement were mea-
sured. In Fig. 4.28 the force-displacement test data compared with the simulation
results are depicted. Both indenter positions show sufficient agreement since the
simulation data lie within the corridor of equilibrium elasticity. As can be seen in
Fig. 4.28 a, b, hysteresis effects are small compared to those shown in Figs. 4.26 a,