I am trying to perform a NX Solution 601 analysis of a composite laminate so that I can use the nonlinear contact features in Sol 601. I am however backed into a corner. If I model the laminate layer by layer the model is absolutely enormous to get a decent element aspect ratio (>10M DOF). I...
I have created a model of a dent using Multi-linear Isotropic Hardening in ANSYS. The model is being loaded and unloaded in multiple time steps using an impactor with an enforced displacement. We are trying to check this model to determine if we have accurate results, and my DER has suggested...
Are there any referencable methods for determining how much step change in thickness needs to occur in a plate to provide at least simple support for buckling? We are assuming a 50% change in thickness forms a support. I've heard of an old BDM method that said 20%, but we can't use that...
I am looking for a copy of Lockheed Report 2072. Does anyone happen to have a copy? It is referenced in the interaction equation section in Bruhn (C4.22).
We are having an interesting debate here at our company. The debate stems from using linear FEM model stresses to predict failure of a material at Ftu. One side is arguing that the linear stress can be used to predict failure based on Ftu due to the example of an axially loaded bar. Obviously...
I have come across some tension fitting analysis that seems to misuse the assumptions of Lockheed Stress Memo No 88a. The analysis uses an angle type fitting and arrives at a value for the variable d that is negative. Since this means that the hole actually lies outside the theoretically...
We have encountered a composites analysis that uses a Hoffman Failure Index criteria to calculate failure. We have been unable to find any reference information on this. Does anyone know about this criteria or can anyone provide a reference that we can look at?
I recently came across a problem that has all of the FEM engineers at our company stumped. I generated a cantilever beam from CBARs and CQUAD4s in PATRAN (using NASTRAN 2001 for the analysis). The beam is 100mm tall, 1000mm long, has a web of starting thickness 2mm and spar caps with...
I am looking for an electronic copy of ANC-5a, "Strength of Metal Aircraft Elements", Subcommittee on Air Force-Navy-Civil Aircraft Design Criteria of the Munitions Board Aircraft Committee, May 1949. Also, if anyone has any information on the history of the 1.15 fitting factor...
I am looking for a set of equations that explain the loading distribution on a single-lap joint that only contains axial load. This condition is mentioned on Page 307 of "Aircraft Structures" by Peery, 1st edition, but no equations are given. References would be appreciated.
