General Mechanical

how to set time for impact load?

• hamzasohailindia
Subscriber
hi,ni am a student and i want to do a low velocity impact load test on a beam specimen, i have created the mdel and applied the velocity of 2.8m/s , but when i solved it, in annimation it i showing that hammer is moving only for small length and comming back to original position and repeateing , but it is not hitting the beam surface, anyone pls help me with this.nthank you, in advancen
• peteroznewman
Subscriber
nIs this a Transient Structural model?nDid you apply a Velocity BC or did you apply an Initial Condition of Velocity?nIs the Hammer touching the beam in the CAD model?nDid you create Frictional Contact between the Hammer and the Beam?nDid you insert a Contact Tool under the Connections folder to check the Initial Contact Status?nWhat was the time increment and end time?nWhat is the first natural frequency of the beam?nWhat is the mass of the hammer?nWhat is the mass of the beam?nPlease insert some images in your reply.n
• hamzasohailindia
Subscriber
I USED EXPLICIT DYNAMICS.nNO HAMMER IS NOT CONTACT OF BEAM.nMASS OF HAMMER IS 4.5KG,.nI HAVE APPLIED THE PHOTOS PLS GUIDE WITH THE TIME I HAD PUT SOME RANDOM TIME VALUES,.nACTUTAALLY, IN MY STUDY I WANT THE HAMMER TO HIT SUFACE OF BEAM FROM 0.4M HEIGTH AND AGAIN THE HAMMER SHOULD GET BACK TO ITS POSTION AND THEN AGAIN IT SHLD HIT SURFACE AND THE PROCESS SHLD CONTINUE TILL BEAM FAILURE, SINCE I NEED THE NO. OF IMPACT AT WHICH THE CRACK GENERATION TAKES PLACE AND THE NO. AT WHICH BEAM FAILS.nn
• peteroznewman
Subscriber
nThe hammer should be positioned in CAD tangent to the beam. What is that projection on the bottom of the beam? Are you trying to do some local damage?nThe hammer should not have a Velocity boundary condition. Delete that.nThe hammer should have an Initial Condition of velocity. Create that.nYou should perform a Modal analysis on the beam supported at the two points and learn the first natural frequency.nYou should try to evaluate this in Transient Structural as well as Explicit Dynamics.nWhat do you know about the material properties of the beam, especially the strength properties for failure?nIt is difficult to simulate multiple hits of a hammer.n
• hamzasohailindia
Subscriber
the below peojections are supports sir, is it correct to keep the hammer in air or shlud i bring it in contact of beam?ni will do the other corecctions sir.ncan you explain me how i can do multiple hits,nthank you sir.n
• hamzasohailindia
Subscriber
sir i have compressive srtength, tensile strength, density of concreten
• hamzasohailindia
Subscriber
• peteroznewman
Subscriber
nDo you have a single impact working? Please show some results.nThe hammer should be touching the beam at the start of the simulation.n
• hamzasohailindia
Subscriber
the 1st pic is of steel just did for trial, 2nd one of concrete beam, i am facing the prblm , the hammer is not stopping just after hitting the suface it is cntinuesly moving down till the beam fails.. nany suggestins pls sirn
• peteroznewman
Subscriber
nIn the 1st pic, there is a Velocity boundary condition. Delete that. That is the reason the hammer does not stop after hitting the surface.nIn the 2nd pic, I see you have deleted the Velocity BC and have a Velocity Initial Condition. That is correct.n
• hamzasohailindia
Subscriber
nyes sir i did as you said , but as you can see in 2nd pic the hammer hits the beam surface untill beams fails, but i want it to rebound.ni was thinking , if you have any utube channel and if can teach me through any meeting apps?nif not, pls help me correct the above problemnn
• hamzasohailindia
Subscriber
. nHi sir., I got result for 1 impact. nCan you say me how I can repeat the impacts for N no. Of times?? n
• peteroznewman
Subscriber