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Hi all We are in the process of developing a novel Windmill blade design. We have most of the design criteria defined but one thing is bit unclear: Where is the rotation center for blade twast? And is it the same rotation center along the blade length?

Hi there I've been searching and wondering how to correctly FE-model a populated PCB with components. I get excellent input from Steinberg book, but how to model thia with FE is still a mystery. The Componens will add both mass and stiffness to the PCB, and to model this corectly without using...

Hi Does anyone have experience with shock loads from MIL-S-901 testing? We have been asked to do an analysis of ahip board equipmnet mounted in a navy vessel. What g-levels do we apply?? Thanks for any help. Rgds Bernt

Hi I just wonder what the error #1466 means: "BEGIN BULK" encountered while reading continuation for control card. My Job stops, and I am not able to get results. Any help is appreciated:-)

Why is 11ms on shock loads "Standard"?

Hi I need to find the vibration levels for payload for an Airbus helicopter. I have search both European and US Standards, but I cant find something useful. I know the rpm and No of blades for the main rotor, but I assume there's a lot of other vibration sources like the tail rotor, engine, gear...

Hi everybody. Is there a good method of adding the static g-forces to a vertical frequency dependent SRS analysis?

Hi Is it possible that a SRS input of 2G responds with almost 0 stresses. (actually 0,004MPa) The SRS has a max acce between 0,6 and 0,9 Hz, whereas the lowest natural frequency of the system is at 4,2 Hz. Appreciate any help here.

I would appreciate some help regarding analysis of SRS in MSC/NASTRAN. I have generated a SRS from a (close to) a half sine shock in the time domain, and want to use this as an input in MSC/NASTRAN sol 103. What about the damping? I alredy defined a damping when generated the SRS (The SRS was...

I'm in the process of calculating bolt forces from loads applied to a FEM model. The FE model is basically built from 3D tet elements. In order to save CPU time, I'm wodenring: Will the bolt forces be influenced by using linear tet elements and not higher order tets? Any with experience in this?

Hi I'm in the process of calculating bolt forces from loads applie to a FEM model. The FE model is basically built from 3D tet elements. In order to save CPU time, I'm wodenring: Will the bolt forces be influenced by using linear tet elements and not higher order tets? Any with experience in this?

How do you define cracks in metallic structure? At what instance do you define crack initiation? Isn't it always a crack if you just magnify it enough?

I wonder: How many cycles are accumulated in a sine test? If we are sweeping through frequencies and we are hitting some natural frequencies in the process, will the number of (fatigue) cycles be the fn*60 cycles pr minute? Since the time at peak stress will be rather short, will that be real...

Some years back, I got hold of the Automotive Steel Design Manual Chapter 3.5 Designing against Fatigue Filures. I have the hard copy on my desk. I don't know today how I got it, but I think I downloaded it for free. (Legal or not???) When I try to find downloading possiblities on the IN, it is...

Anyone have experience with cross bores in a block. I know the SCF in the corner where the bores are crossing can be extreeme, as we also have experienced. Any ideas as to how to minimize the SCF? Any suggestions are appreciated.

Just recieved a Webinar invitation from MSC "Expediting Shellmeshing.... With todays computer power, I wonder why we are even bothering with preparing a 3D Solid Model to accomodate Shell meshing. That can take quite some time. Why not just take the Solid model "as is" and mesh it with TET's or...

I have several times encountered companies that asks the question: Why should I bother doing detailed engineering? We do some simple, but logical considerations and invetigations on our system, dig into our experience database and design our system. When you tell us to spend 10k $ for telling us...

Hi all I have composite layers reinforced with steel for attaching other equipment. Ply1 and the last ply is steel and defined as Isotropic material. All plies in between are composites and defined as orthotropic. When I try to post-process results, I can't get ply results from that particular...

Hi composite experts I'm a little confused as to the difference between defining lay-ups in Layup modeller and defining in my 2D collector. It doesn't seem to me that the two are "talking" to each other. Appreciate any enlightment on this matter.

Hi all I have a kind of philosophical question. Is there an upper limit to a SCF (Stress Concentration Factor)? If you have a perfectly 90 deg corner without any radius (fillet), would the local stress in the corner be infinite? I have not been able to calculate one with FE analysis. The finer...