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sigma = F / A [N/mm^2]=[N]/[mm^2]

It depends from the solver used. Nastran for example seems to give wrong results using any solid element except hexa. Pressure load for example.

How to extract correct outer cap frame fastener loads by a Global FEM rapresenting aircraft in the current manner: _________ |____|____| |____|____| |=frame as cbeam ___ ___= skin panel 1 stringer bay CQUAD In general for frame fastener load i use cquad xy shell force extraction for left and...

Pre-tension not simulated in fem is a good question. The real loads and stress will be higher than those seen as results.in fem you can simulate it only in one way.in fem you can use a preload at both nodes at each side.tension load.but in general is useful to proceed analitically.Use ESDU.pay...

Pressure or force applied beetween part connected by bolts on the flanges connection line is not relevant for bolts. If beam give compression is because you cannot simulate contact of flange but bolts will be surely unloaded in reality.Bolts have not to be sized for this case.In general for this...

FOR Static Niu - Airframe ..... Stress and Design FOR F&DT AFGROW : http://www.siresearch.info/projects/afgrow/index.php HANDBOOK OF DT DESIGN USAF: http://www.siresearch.info/projects/dtdh/pdfs.php

with nastran and patran you have 2 choice: 1) try using mpc rbe2 with 1dof and node edited to analisis cid so that 1dof is allined with this axis. than you can simulate contact with an iterative procedure so to remove to your analysis group all mpc constraing your flanges.your aim is to obtain a...

Can MPC RBE2 with 6 d.o.f. be used correctly to simulate bolt in FEM instead of bar and other things.....The mpc shape i'm talking is to create from a 3d model an indipendent node at one face and all dipendent connected in an umbrella shape...the other face of the same solid the other node and...

Thank you for your so helpful and deep answer. ...and for shear resultant on bolt?always in multiple layer configuration. thank you in advance.

I'm trying to simulate flanges contact in patran using gap element for 2d element. can someone help me to find another way? even connecting not allined nodes?

To make a good correlation predicting test results by FEM forecasting don't forget mohr theory and how stress are related to strain. i suggest to you before checking your model to see strain theory because gauges give apparent stresses and fem gives real stress.

i'm talking of metal and in particular aluminium alloy

someone may help me on algoritm to define to build stress-strain curve for non linear material analysis?

For analysis of thin plate the best thing is to perform by nastran the sol105 to reach first buckling mode and then sol106 by large displacement and no follower force so to define using non linear geometrical analysis the behaviour of your structure and the maximum load for investigation.The...

Ok. But how simulate rosettes? Can I use rod? I'm tring A=0.001 And material E=1. ni=0.3 dens=0. th-exp=0 also for rosette but i think that it is not correct because this don't take in account the shell z1 or z2 face and so on. pbeam seems to me more correct i'm tring also I1=I2=0.001....but is...

In general to to evaluate and predict the stress results of gauge readings i read on fem for example the stress on a reference cid along the direction of sensor on quad element taking into account the z1 or z2 face...I think that there is another way to evaluate the sensor value using for fem...

It depends naturally to the user.it is arguable. I suppose Concrete Softwares are the best one.

Offset vectors gives wrong results in solution sequences that compute differential stiffness (NASTRAN SOL 105 and 106) and so when temperature load is assigned at nodes (NASTRAN SOL 101 too) reaching additional non realistic bending stress.A simple test can be done assigning offset in pshell for...

In general i use vonmises for 3d modelling and for 2d max/min 2D principal stress...even if performing plastic analysis it is required to read in vonmises stress i prefer the second one also in linear analyses because of is more conservative for 2D fem.In compression what to read?vonmises is +?

Supposing to have 3 fem/quad layers and a 2 allined cbar simulating fasteners crossing them.I'm in doubt about tension element results if summing (supposing 3 layers)the 2 bar element forces is as to say having resultant tension acting force on bolt....it seems to me that single element can give...