The model files used in this problem are available in:
/radioss/verification
Model Description
Units: Mg, s, mm, MPa
The model contains 5 spring elements with the same length of 100 mm and different
properties.
Common parameter
Mass = 1E-5 Mg
Linear stiffness after locking = 1000 N/mm
Spring 1
Initial pretension force = 1000 N
Maximum retraction value = 50mm
Spring 1
Spring 2
Spring 3
Spring 4
Spring 5
Initial force = 1000 N
Max.
retraction = 50 mm
Force versus retraction defined by
curve
Force versus retraction defined by
curve
Force versus time defined by
curve
Force versus time defined by curve
going to 0
Ilock=1
Ilock=1
Ilock=2
Ilock=1
Ilock=1
Imposed displacement is defined on one end of the spring element to model the
reaction behavior from the seatbelt with initial retraction followed by tension and
retraction. Figure 1.
The other end of the spring element is clamped.
Results
Computation results for the force versus elongation. Figure 2. force version retraction and time
Theoretical value for the force according to time or retraction value.
Table 1. Theoretical Results
Time (s)
Retraction (mm)
Spring 1
Spring 2
Spring 3
Spring 4
Spring 5
0
0
1000
1000
1000
1000
1000
0.1
45
100
350
350
1000
1000
0.2
44
2100
2350
2350
3000
3000
0.3
46
80
280
-1650
1000
-1000
0.4
45
2080
2280
350
3000
1000
Conclusion
The Radioss computation returns results very close to the
theoretical values with the expected behavior for the retraction behavior.
