I have a model (ball) and would like to get the its eigen frequencies and eigen vectors (modal analysis), in fact i should not need to apply loads, it is just solution to K-w^2 M = 0, how can it be done

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The default value of penalty stiffness scale factor in Ansys-Lsdyna  is 0.1, when one varies this value, he/she obtains different results, the question, how can one  know the right value of penalty stiffness scale factor?

I am simulating the impact of a 6mm - diameter steel solid ball with a rigid falt surface using Ansys-Lsdyna. the speed of the ball at the impact moment  is low (from 1 to 10 m/s). specificly, i am intersted in the period between  just touching and  just leaving the ground for the first impact.

how to plot the total kinetic energy vs. time using ansys (GUI)

how to plot the kinetic energy, potential energy, .. etc at certain vs time using ansys or ansys ls dyna for impact problem

how to refine those hot spots (heigh stress zones) in a meshed
structure using ansys. in fact i have a large body. most of body
subject to very low (negligible or zeor stresses) except few zones with
very much high stress. first i meshed my body with coarse mesh and i
noticed those area which i expect them from experimental results now
how can i refine meshes on basis of von mises stress range.

can one do it with 'select entities'and how?

second question, if i mesh whole the body withfine elements then i
will have mesh density sensitivity problem, it means finer mesh could
be worse the fine one

how to refine those hot spots (heigh stress zones) in a meshed structure using ansys. in fact i have a large body. most of body subject to very low (negligible or zeor stresses) except few zones with very much high stress. first i meshed my body with coarse mesh and i noticed those area which i expect them from experimental results now how can i refine meshes on basis of von mises stress range.

can one do it with 'select entities'and how?

second question, if i mesh whole the body withfine elements then i will have mesh density sensitivity problem, it means finer mesh could be worse the fine one

I used the drop test module to simulate elastic ball impact with flat flexible surface of the same ball material properties . i meshed the whole ball with hexahedronls dyna element

at certain mesh size, good results of  3% error. but i still have the problem when i
refine the mesh gradually (for whole ball) the finte elemet curve and
hertz curve (the correct results) get closer until i reach certain refinement (which is not
too fine) ansy ls dyna curve start geting further from  hertz curve
until it coincide approximately with the 1st mesh (the coarser mesh),
what is the problem? is it the time step?or what?

Dear Readers

Dea readers

This question seems easy but in fact it is NOT. i do not know how to mesh a ball with ONLY brick elements (no tetrahedron) using ANSYS. Please kindly send me an input file contains the meshing to a.abeed@tu-bs.de

i am a student. I would like to simulate impact of an elastic solid ball with rigid flat surface, I do not know how to create the best mesh for the ball so i obtain good results with ansys LS Dyna (drop test modue). of course there are some advice in DTM like avoiding tetrahedron or sharp edges, ... etc. please help me i think a ball meshed with brick element produce better results but, how can one mesh the ball entirely with only  bricks (no tetrahedron)

A cantilver beam is connected to a closed box. 3 balls of different sizes and materials are inside the box. the beam was draged litle downward from the middle and then left to vibrate freely. of course, during the vibration, the balls will colide with the box walls and with each others. The question: is it possible to simulate this system with ansys? if yes, How?