in my model , zeroLength element was used at the boundary between bridge abutment and deck. the abutment node is fixed, and no mass.
zeroLength element udsed Impact Material，the stiffness of the girder is ：EA/L. But when i change the stiffness , 0.1 EA/L ,then i output the displacement of beam-end, it is larger than the sum of gap and δm (δm is the maximum penetration during the pounding event).
For example,the gap is 5.0 cm, the δm is 2.54 cm, but the displacement of beam-end is 10 cm or more.
And the force of the zeroLength element is large than the Fm(the limit value of ImpactMaterial ).
Whether or not it is could happen, or there is problems in my model.
i do not know it is why.
Impact Material
Moderators: silvia, selimgunay, Moderators
Re: Impact Material
which material are you using? .. the standard impact material has no max penetration parameter, quite frankly none can .. all they could do is increase the stifness to such an extent that there would be very little penetration beyond some max event..
Re: Impact Material
hello，fmk.
I'm very glad to receive your reply.
in my model ,i use the Impact Material:( uniaxialMaterial ImpactMaterial $matTag $K1 $K2 $δy $gap ), in which the δy = a * δm ,
( δm is the maximum penetration during the pounding event ),so i think the displacement of beam-end can not exceed the sum of gap and δm . whether or not it is right about my opinion.
last night, i consider the problem again, whether or not the δm is only to determine the δy , the δm has nothing to do with the displacement of beam-end (the penetration ).If this is the case ,the displacement of beam-end can exceed the sum of gap and δm .
i want to study the effect of the stiffness,so i change the stiffness of the girder , when the stiffness is 0.1 EA/L, the displacement of beam-end exceed the sum of gap and δm.
I'm very glad to receive your reply.
in my model ,i use the Impact Material:( uniaxialMaterial ImpactMaterial $matTag $K1 $K2 $δy $gap ), in which the δy = a * δm ,
( δm is the maximum penetration during the pounding event ),so i think the displacement of beam-end can not exceed the sum of gap and δm . whether or not it is right about my opinion.
last night, i consider the problem again, whether or not the δm is only to determine the δy , the δm has nothing to do with the displacement of beam-end (the penetration ).If this is the case ,the displacement of beam-end can exceed the sum of gap and δm .
i want to study the effect of the stiffness,so i change the stiffness of the girder , when the stiffness is 0.1 EA/L, the displacement of beam-end exceed the sum of gap and δm.
Re: Impact Material
the dm looks like a parameter you use in your determination of the input properties. i would say it is an expected maximum penetration that is used to calibrate the properties of the material. it is not some limit thta the material is going to enforce.
Re: Impact Material
thank，very much，fmk. now i know it .