Hi,
I am trying to create a numerical model for bullet penetration. In the experimental part 300 mm x 300 mm panels of varying thickness were subjected to Ogive nosed bullet impact from 7 ft with a muzzle velocity of 900 m/s. Panels upto 50 mm were perforated by the bullet with crater and scabbing on front and back face respectively. The 75 mm panels had partial penetration with crater and scabbing on the front and back face. The 100 mm panel has only penetration till a certain depth with only crater on the front face.
Ls-Dyna is being used for numerical modelling. Mat_072R3_concrete_damage_rel3 (K & C model) has been used as constitutive model for concrete. Bullet has been modeled as a rigid part. Mat_add_erosion has been used to depict the crater and scabbing. The material strength used was M15. I am attaching the keyword file for a 50 mm thick panel. The units for the model are Kg, mm, sec, N. I have kept the termination time of 5e-5 secs to observer the results however the complete penetration takes 9e-5. The material parameters for mat_072R3 were initially generated automatically using -fc as A0 (max shear failure surface parameter) as recommended at page 2-359 of LS-Dyna User Manual Vol 2. It was observed in post-processing that the bullet is penetrating the panel with erosion of elements however stress wave propagation was not observed due to which no crater and scabbing was formed. In the attached keyword file the parameters for mat_072R3_concrete_damage_rel3 have been calculated as per Malvar et al (1997); "A plasticity concrete model for Dyna3D".
I would appreciate any suggestions as to why cratering and scabbing is not observed in the model.
I am trying to create a numerical model for bullet penetration. In the experimental part 300 mm x 300 mm panels of varying thickness were subjected to Ogive nosed bullet impact from 7 ft with a muzzle velocity of 900 m/s. Panels upto 50 mm were perforated by the bullet with crater and scabbing on front and back face respectively. The 75 mm panels had partial penetration with crater and scabbing on the front and back face. The 100 mm panel has only penetration till a certain depth with only crater on the front face.
Ls-Dyna is being used for numerical modelling. Mat_072R3_concrete_damage_rel3 (K & C model) has been used as constitutive model for concrete. Bullet has been modeled as a rigid part. Mat_add_erosion has been used to depict the crater and scabbing. The material strength used was M15. I am attaching the keyword file for a 50 mm thick panel. The units for the model are Kg, mm, sec, N. I have kept the termination time of 5e-5 secs to observer the results however the complete penetration takes 9e-5. The material parameters for mat_072R3 were initially generated automatically using -fc as A0 (max shear failure surface parameter) as recommended at page 2-359 of LS-Dyna User Manual Vol 2. It was observed in post-processing that the bullet is penetrating the panel with erosion of elements however stress wave propagation was not observed due to which no crater and scabbing was formed. In the attached keyword file the parameters for mat_072R3_concrete_damage_rel3 have been calculated as per Malvar et al (1997); "A plasticity concrete model for Dyna3D".
I would appreciate any suggestions as to why cratering and scabbing is not observed in the model.
