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Hi,I am trying to simulate a bird impact on a plate with RADIOSS. So I am creating my model on hypermesh now, i chose to consider the bird as a fluid with a density of 438 kg/m3. I would like to work with SI units and the dimensions of the bird are : 0.1325m long cylinder with two hemisphere ends having a radius of 0.075m. I am now trying to mesh this geometry with the SPH module in hypermesh. So i entered a pitch of 1e-3m and a density of 438kg/m3 as i said before. But when i create the mesh, nothing happen and i only get this message "0 mass elements created". I attached my file with the topic. I don't know what could be my error, more of that I tried to do it using mm instead of m and it worked... But I really want to use SI units. Thank you in advance for your help, Gaspard. BirdStrikeSI.hm
Hi I'm now working on BirdStrike Analysis using RADIOSS140. Like many paper on birdstrike analysis reports, I've done a reproduction of birdstrike experiment carried out by Wilbeck in 1977 . The resultant pressure PH(*1) and PS(*2) meets with theoretical value very well. Except that,if you look at the pressure curve, there is a "ZERO Pressure" period just after the first contact. Taking closer look into the animation, the SPH bounce back just after the contact. Such blank period doesn't appear in the experiment result,or analysis results of other researchers report. [Question] : Is there a way to correct this ? Model setting is follows. -bird is using SPH. Material law is MLAW6 (Equation of State). -Using contact TYPE7. Istf = 1 StFac = 550 … recommended value by Altair Support Igap = 0 gapmin = h/2 (h = SPH radius) … recommended value by Altair Support I've varied the value of these parameters which didn't make any difference on "ZERO Pressure" period. ******************* *1 … PH: the peek pressure just after the contact(Hugoniot Pressure) *2 … PS: the constant pressure when bird deformation can be seen as constant flow.(Stagnation Point Pressure) :J. Wilbeck,AFML-TR-77-134 1977 161121_Bird Strike experiment reproduction by RADIOSS.pdf