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Thanks Corypad. One more question: Would it make a difference if the rivet positions are painted over after installation? Assuming the paint stays intact, is there still a concern of corrosion with the dry installed rivets?

Hi, I am hoping someone can help me with the following problem: I have 3 metals in contact: An OS212 Steel bracket (Passivated+painted) connected via titanium rivets(Anodized) to an Al2024-T351-HDT Sheet (Anodized+painted). Although all three components have some form of corrosion protection...

Thanks a mil hetgen. While I have your ear, if my structure is a signboard with steel poles fixed into a bed of concrete (lampost), the moment due to the wind is reacted as a bearing load in the cement at the base. I know in aircraft structures, we would treat the base as a lug and check the...

Hi hetgen, Thanks for the answer. So you are reading that sentence to mean that K has a value of 0.02, as opposed to what is the K value of variation of the extreme value distribution of 0.02. That sounds logical. Is it common practice to factor down the wind load depending on the expected...

Hi, I have read most of the posts here relating to wind loading on structures, but have not read the specs from different countries-so please don't be upset if this is clear in other codes. In South Africa, the wind load code is called SANS 10161-3. For calculating the basic wind speed, the...

No gap, beams are directly on top of each other. Foundation is modelled as a solid block of material and constrained at its base. I'll post some pictures of the model and results tomorrow.

rb1957 - Your conclusion of an infinite couple is correct if we are using a standard Winkler foundation model. However, this is at odds with my contact FE model of the same system, and that is where the problem lies. I suspect that the FE is correct in this case.

I am investigating prying action in a riveted joint subjected to a tension load. The centroid of the overhang pressure distribution determines the prying load on the rivet. To model the contact effect in Patran, I modelled the overhang beam and simply varied the E of the foundation from soft to...

Hi prex, By imposing my boundary conditions on the differential equation for the deflection of a beam supported on an elastic foundation, I get the value of the four constants of the characteristic equation: y =...

Hi Alakin. I got my TET10 model to run thanks to help from MSC. First of all, I am using Nastran 2012; not sure if this works for any earlier Nastran versions. Secondly, if you are using higher order elements like TET10s, you need to change the following: In Analysis>Solution Type>Solution...

Hi, I am investigating the overhang beam pressure distribution when part of the beam is resting on an elastic foundation. We are all aware of the assumption that when a moment is reacted at the foundation, the reacting end beds-into the foundation and creates a triangular pressure distribution...

Hi Alakin, I am having the same problem. Did you find a solution? Does the job run successfully if you change to Tet4 elements?

With a little help from Physics Forum, Wikipedia and BAretired's picture, I finally have the solution. Excuse the bad hand-writing, I was excited... Thanks everyone. http://files.engineering.com/getfile.aspx?folder=645b7a8b-f8b7-4dde-bea2-5cd6ea9a8dd8&file=Elastica_derivation.pdf

Thanks Everyone. dhengr - a brief look through Timoshenko's "Theroy of Elasticity" yielded no derivation of the elastica I am considering. BAretired - thanks for the picture, but they also seem to jump a few crucial steps in deriving the formula that I cannot replicate. Any more suggestions?

Hi. I would like to derive the classic Bernoulli/Newton elastica curve from first principles. Bernoulli's/Newton's classic elastica equation is of the form: 1) curvature = dθ/ds The RHS reforms to the well known elastica equation: 2) dy2/d2x/(1+(dy/dx)2)3/2 But how do I get from 1) to...

Hi again. I am now using a different approach. Denial, I think that you are right-the varying Winkler foundation is not the way to go. I now add the stiffness of the beam and backup cantilever together and obtain the elastic curve. Then I use Excel's Goalseek to predict the bolt force and...

Interesting insight into the problem... You're right about the continuity in the backup beam, but I thought it would be adequate to assume that the springs act independently. You would know from textbooks such as Niu and Flabel that they assume a triangular pressure distribution on the...

Profuse apologies again Denial.

Thanks for the advice Denial, and sorry for cross-posting. The problem I am investigating is a beam, fastened on one side to a back-up cantielever beam. The overhang footing beds into the backup beam and the moment arm to the centroid of the "bedding-in" distribution determines the prying...

Hi, The following is the differential equation for a beam on a varying-stiffness elastic foundation. Essentially the beam sits on a cantilever, whose stiffness varies to the third power with length. Does anybody know how to solve such an equation as a closed form solution (if possible)...