Optimization Potential of the Method - Preventive Biomechanics - page 331

Fig. 7.55 a Optimized seat surface contour in the transversal plane and b mechanical interaction
with male model E-BCSS-3 exhibiting reduced tissue stress, particularly beneath the ischial
tuberosity

Table 7.9 Maximum stress values S 11 ,S 33 and S 12 prior to and after shape optimization (in the
transversal plane)

Mises S 11 (MPa) S 33 (MPa) S 12 (MPa)

Max Tension Compression Tension Compression Max Min

Prior to optimization 0.0070 0.0041 -0.0123 0.0027 -0.0122 0.0019 -0.0013

After optimization 0.0040 0.0030 -0.0071 0.0020 -0.0074 0.0009 -0.0005

when referring to the coordinate system, as given in Fig. 7.61 . Therefore, S 12 and
S 11 , derived from simulation in the transversal plane, transform to S 23 and S 33 ,
respectively.

7.3.1 Optimization of Car Seat 'B' Under Male Boss-Model
Loading

7.3.1.1 Surface Seat Cushion Contour in the Transversal Plane

Figure 7.54 a depicts the initial unloaded non-optimized seat surface contour in the
transversal plane of car seat 'B' introduced in Fig. 6.35 b . Figure 7.54 b depicts the
deformed tissue and seat materials under gravitational body weight loading as a
result of the mechanical interaction with 'E-BCSS-3', in terms of a S 22 stress
contour plot. The maximum tissue stress occurred underneath the ischial tuberosity
(note: in the following and as is common practice, negative and positive stress are
referred to as compressive and tensile stress, respectively, and for clarity are
indexed with ''c'' for compression and ''t'' for tension).