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Thank you everyone for your replies. I can justify hand calculations with safety factors for static loads, like the above example. However, many of the components that I analyze experience dynamic loading that is hard characterize, and a welded component can experience varying loads - either as...

Hello, I am not an electrical engineer, so please be patient with me. I'm trying to simulate a waveguide with a dielectric material load. I've set a source power of 1 W. The waveguide cross section area is 84 cm^2 If I plot the electric and magnetic fields along the cross-section of the...

I've analyzed a jib crane design analytically and via FEA. The FEA results do not match up with the analytical calculations. For example, when analyzing this connection between a piston and a post: I assumed this weld pattern: with the welds being 9 mm fillets. The connection is loaded...

"Fatigue evaluation of welds using FEA is really common in various industries. There's even a separate module in one of the main fatigue analysis programs meant for such studies and it uses the structural stress method which is mesh-insensitive in theory." I'm having a hard time understanding...

"I don't get why people want to FEA welds." I want to analyze a structure that undergoes cyclic loading. The welds, or the areas adjacent to the welds, are going to fail well before the parent components. The welded joints and loads are not straightforward. How do you recommend that I analyze...

I am analyzing weld stresses during vibration for fatigue. The mesh consists of shell elements. When modeling fillet welds, I set the weld size to half the actual weld size, to simulate a mid-surface. I set the weld elements thickness to the effective throat size: The weld is modeled using...

@SWComposites, can you elaborate? The 1D elements on the washers are RBE2 elements but the 1d elements in the other components are RBE3 elements.

Wouldn't including pasticity just give me a more detailed simulation of the post-yield behavior? I'm saying that the current results that are showing yield seem way too high, especially since the physical test shows a much smaller deformation and no signs of plastic deformation.

The material is linear, which is why I'm ignoring the actual stress values beyond yield, and just noting the fact that the material has reached yielding. The nonlinear analysis is to allow for changing contact status. If I set a frozen/bonded contact between the components, I get additional...

I've modeled a rectangular tube being clamped via a pretensioned bolt: The tube is 10 mm thick (steel) and is fixed at one end. The pretension force is 50 kN. I also modeled a 50 kN nodally-distributed force on the washers of another connection, to compare the results: The contacts between the...

Thanks GregLocock for your posts and calculations. I think you are right. When I was building and testing the apparatus, I was able to affect the current consumption by changing my posture, especially by locking my knees at higher frequencies. I skimmed through a couple of articles by Mansfield...

I had one accelerometer, mounted on the platform, that was feeding the controller. I was expecting the system to stutter and the shaker to trip the overload safety but it seemed to not even break a sweat. The platform itself was not extremely rigid (it was made of wood) and the load was a human...

I've already run the vibration test and it worked. The problem is I cannot explain why. The shaker vibrated the mass at frequencies where my (and your) calculations showed it could not. This puzzles me.

I've attached the V456 Data sheet. It's the only one I have. The shaker's max force is 489 N. Well below the force required to directly vibrate a 100 Kg load. So I added springs with the intention of exchanging the springs every 10-15 Hz as I thought the shaker would attempt to accelerate the...

I've attached a list of desired accelerations. Can you elaborate on the governing equation becoming F=ma at f>2fn? Thanks.http://files.engineering.com/getfile.aspx?folder=cf234192-11ca-4979-9a31-1c79466d1a5e&file=accelerations.JPG

This is not homework. The shaker is an LDS V456. The amplifier is an LDS P1000L. The controller is an LDS VLL1.

I designed a spring and mass system (damping unknown) that is vibrated by applying a sinusoidal force to the mass using an electrodynamic shaker. The mass is estimated to be 100 Kg. The spring is actually 4 springs, each with a k value of 63.55 N/mm, supporting a platform (one spring at each...