Johnson Holmquist Ceramics

In recent years johnson holmquist and their coworkers have developed a series of constitutive relations to simulate the response of ceramic materials under large strain high strain rate and high pressure impacting conditions.

Johnson holmquist ceramics.

The constitutive behaviour of alumina ceramics at high strain rates was quantified using the johnson holmquist material model with damage jh 2 a widely accepted model for brittle materials subjected to high loading rates high pressure and large deformation. Implementation and validation of the johnson holmquist ceramic material model in ls dyna inproceedings cronin2003implementationav title implementation and validation of the johnson holmquist ceramic material model in ls dyna author d. The johnson holmquist model for simulating impact and penetration into ceramic and glass materials is commonly used in continuum hydrocodes. The first version of the model jh 1 did not allow for progressive damage of the material.

The compression tests simulated for verification of determined jh 2 constants and finally validated by conducting the eoi simulations on glass plates to the spherical and cylindrical shaped projectile. The armor structures were subjected to 7 62 mm ogive nosed steel projectile impact. Kaufmann and grant j mcintosh and todd berstad year 2003. In order to define proper material behavior johnson holmquist ceramics material model for b 4 c and plastic kinematic material model for al6061 t6 4340 steel and epoxy resin was used.

By incorporating the compression and tensile test data johnson holmquist ceramic jh 2 model parameters were estimated for aluminosilicate glass. Experimental results for aluminum nitride aln together with data available in the literature indicate that a mohr coulomb criterion and the johnson holmquist model fit the experimental data for failure in a brittle manner whereas the ceramic material exhibited pressure insensitive plastic flow at high pressures. The johnson holmquist model commonly used for cera mic materials was enhanced by riedel and co workers 30 31 leading to the rht model.