To all,
Does anyone know a good source/ref for the equations used by (nastran) RBE2 element to get the load distribution assuming a force being applied at the independent node? I remember seeing something in the old msc.nastran manual but cannot find it anymore
If one was to set-up a simple...
To all,
A question about the modal approach of solving response for a random analysis
With my test FE Model I de-selected 1 mode and compared the PSD response (acceleration) to a prediction will all the modes. The mode selected has a mass participation of 2%
The PSD response with the mode...
To all,
Consider the formula for fatigue damage formula using Steinberg (ST) and the Narrow Band(NB)
Has anyone ever plotted the ratio D_NB/D_ST as a function of the SN curve exponent (b = 3..13)?
If I got this right (and I am not sure I have hence the question!) the ST method is predicting...
To all
What is the knock down factor I need to apply to a mean stress to get reliability = 99% with a confidence level = 95%?
I am mixing up my basic stat an need a refresher on this one!
Assume I have a sample size n = 1 (only going to test the system once!)
Thanks
Regards
To all
I’d like to know if there is a way of estimating the effect of an impact on a composite panel. I am not after some fancy FE analysis. Just a rough idea/back-of-the envelope calc type of approach
Given the mass (of the object) and its drop height I estimated the impact energy at 5J. To...
To all
If one run a standard random analysis with Nastran and wants to post-process the rms displacement: Does one request the rms displacement relative to the excitation node? I want to check by how much the node move for the random profile
Thanks
Regards
In relation to an old thread
http://www.eng-tips.com/viewthread.cfm?qid=338665
Am I correct to say that there is a "optimum" thickness ratio (t2 = 1.5*t according to my plot) where the shear stiffness calculated using Huth formula is maximum?
While doing a sensitivity study (frequency) I came...
To all
I am looking for some suggestions / explanation on the following. I came across a simple fatigue estimate in a report. What I don't really understand is the "correction" of the SN curve from the data in MMPDs for 84% probability of survival. MMPDS is giving the SN curve for 50%...
To all,
While doing some reading on FE related matters I came across the statement: displacement formulation always lead to over stiff representation of the structure
While I am fully aware of the issue of elements such as the 4-nodes tetra (the famous TET4) being too stiff and requiring a...
To all
I am looking for info on the effect of stiffness/flexibility on bolt load distribution for a ring-type of plate. Consider the following
A part like a flange (diameter D, thickness t) with N bolt on a PCD d so that d < D. A basic load balance at the CofG of the bolt group produces a...
To all,
If one considers a standard bolt group analysis (say a square pattern in the XY plane) with an applied load (Fx) at the centre of the bolt group
Shear force/bolt = Fx/4
If one however considers a square plate with full constraints at its 4 corners and a load in the x direction then one...
To all
Before I "dive" back into my book on the FE method I thought I ask the question
Assuming a model made of 2D elements (shell) with a thickness 't' (let's say t=5mm) and the surface of interest being much larger that 't' (assumes a square 1000mmx10000mm) if one keeps refining the elements...
To all
I have an FEM with stress value in an area of interest. Stress is a bit too "high" and is deemed to be the result of the modelling technique used (RBE2,etc).
One does not want to remodel the area as it will most likely create issue. It is known that in that particular area an extra...
To all stress engineer dealing with ECSS-E-HB-32-23A -Threaded Fastener handbook
I was pointed to ECSS-E-HB-32-23A for the checks of fasteners by the customer. Looking at ECSS-E-HB-32-23A dated 16 April 2010, equation 9.2.6 in section 9.2.3, could anyone confirm if the equation “returns” a...
To all,
Started learning Dictionary to deal with data from an engineering software. So far so good…
I am looking for a way of getting the max value in the dictionary and then get the key related to that max value. Dictionary (Of Integer, Double) representing (Node ID,value). According to online...
To all
Does anyone know if there are similar formula to Roark's formula for rectangular plate with uniform pressure but for tapered plates? Have done some web search and so far have found nothing relevant
Thanks
Regards
JXB
I am playing around with a test case to check something. See attached .dat file. I modelled a plate with some connections (CBUSH) and applying a Force FX=1000N on the edge of the plate. 2 of the “fixings” are only carrying shear load (X&Y). I deliberately offset these 2 “fixing” as part of the...
To all
I am playing around to model a bolted connection (4 bolts with 1 dowel) attached to a beam. See attached picture.
The beam is attached to the 1 end of zero length cbushs via an RBE3
the other end of the cbushes is attached to a fully grounded master nodes via an RBE2.
I am having...
in relation to post
6082-T6 equivalent in MMPDS-06? http://www.eng-tips.com/viewthread.cfm?qid=386873
Does anyone know what would be the nearest equivalent for Stainless Steel
Corrosion Resisting Steel S143D to BS 2S 143 and/or S145D
Thanks
Regards
JXB
To all,
I am bit stuck. I am using 6082-T6 stress allowable but was adviced/told (by the customer) that;
1. (strength) data must be taken from MMPDS-06
2. knock-down factor (strength reduction) must be taken at 200degF
Question is: Does anyone know what would be the equivalent to 6082-T6 in...
