Week - 1 - Consistency of Units

AIM: The main aim of this week challenge is to know the consistency in units.Since Ls-Dyna does not have a default unit system we need to understand how to derive the value that you need to input for various material and property cards.

PROCEDURE:

The calculation done below is to convert the SI units to gm/mm/ms units.

1. MASS

1kg = 1000 gm

2. LENGTH

1m = 1000 mm

3. TIME

1s = 1000 ms

4. FORCE

5. STRESS

6. ENERGY

7. DENSITY

8. YOUNG'S MODULUS

9. VELOCITY

10. GRAVITY

In the below table the conversion for all the units are given

Input	Mass	Length	Time	Force	Stress	Energy	Density	Young's Modulus	Velocity	Gravity
kg cm ms	1	100	1000	0.0001	1E-08	0.01	0.000001	2100	0.027778	0.00098
kg cm s	1	100	1	100	0.01	10000	0.000001	2100000000	27.7778	980
gm mm ms	1000	1000	1000	1	0.000001	1000	0.000001	210000	0.277778	0.0098
kg m s	1	1	1	1	1	1	1	2.10E+11	0.277778	9.8
gm cm s	1000	100	1	100000	10	10000000	0.001	2.10E+12	27.7778	980
gm cm us	1000	100	1000000	1E-07	1.00E-11	0.00001	0.001	2.1	2.78E-05	9.80E-10
gm mm s	1000	1000	1	1000000	1	1E+09	0.000001	2.1E+11	277. 778	9800
ton mm s	0.001	1000	1	1	0.000001	1000	1.00E-12	210000	277. 778	9800
slug ft s	0.068	3.28	1	0.223	0.0207	0.731571	0.001927	4353658537	0.911112	32.144
kg mm s	1	1000	1	1000	0.001	1000000	1E-09	210000000	277. 778	9800
g cm ms	1000	100	1000	0.1	0.00001	10	0.001	2100000	0.027778	0.00098
kg mm ms	1	1000	1000	0.001	1E-09	1	1E-09	210	0.277778	0.0098

CONCLUSION:

Thus the given input measurements are converted into respective unit systmes and this is used in LS-DYNA calculation.