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proportional to the element mass and those of human bodies are obtained from a simple experiment.
The values are shown in Table 4.1.
Time Interval
In DEM, a time interval of computation has a strong influence on the stability of results. If the time
interval is too large, the result will diverge. Cundall (1974) recommends the following time interval.
(4.1)
From the above equation, the limitation is Ar /v>
1UUJ
*ytn
AA
AAA
B
A
AA
Q 45 60 75
Fig.5.1 Classification of damage levels
C
B
Chest-G
0 5 10 15 20 25 30 35 40
TIME (sec)
Fig.6.1 Input ground motion
ASSESSMENT OF DAMAGE TO HUMAN BODY
In the field of the car engineering, the values of HIC (Head Injury Criteria) and Chest-G are often used
to assess the damage to human body. We use the same criteria as HIC and Chest-G. The allowance
level of chest is considered to be 60G, and HIC to be 1000. Using these values, the damage level of the
people in the house can be estimated. As is shown in Fig.5.1, the damage level is classified into 6
levels (AAA, AA, A, B, C, D). AAA is the safest level and D is the most dangerous level.
RESULT
We used the acceleration record of Kobe Marine Meteorological Agency during the 1995 Hyogo-ken
Nanbu earthquake to the modeled structures (Fig.6.1). The result of each case is as follows:
Case A
The structure behavior in Case A is shown in Fig.6.2. The structure started tilting at 7.0 second and
completely collapsed at 11.4 second. The computed values of Chest-G, HIC, and the human damage
level are shown in Table 6.1 (a). In this case, joint elements are not considered. Therefore the structure
easily collapsed and crushed the human bodies. All people are on the worst damage level 'D' and have