3 Replies Latest reply on Dec 17, 2007 8:16 PM by Benjamin Reilly

    Pressure Exerted on a weldment

    Benjamin Reilly
      I work for a company that manufactures large doors with internal steel skeletal structures that must be engineered to meet windload requirements. I currently model the skeletal structure solo as a weldment, and I want to apply the pressure across the entire face of the door to observe deformations and stress levels. I know the pressure I want (between 25 and 35 PSF depending on location), and can calculate the force it will exert on the door, but I don't know how to apply the load in a beam mesh. I say Beam mesh because it is the quickest to solve with the simple structure of our doors. Is there an easy way to do this? I've tried inserting a thin sheet similar to the cladding most often used (29ga steel), and using a blended mesh, but Cosmos cannot resolve the sheet, any thicker and I would not be representing the door properly.
        • Pressure Exerted on a weldment
          Ameer Chilakala
          We can apply force per unit length on beam section in 2008, during applying the load we have to select the entire beam section. During solving beam analysis they will mostly force per unit length. Kindly go through the cosmosworks 2008 online tutorial, which consists of beam analysis example.
            • Pressure Exerted on a weldment
              Benjamin Reilly
              Thank you for your response. I did find the "per unit length" box, didn't look hard enough before. I re-ran the analysis this way: I took the PSF pressure and multiplied it by the area of the door. Then I took the resulting force in LBS and divided it by the total length of tubing or beams. I then entered this number into the forces box. The model is simplified (no hinges or framed opening) and we only are looking for preliminary type results. It is, however, an assembly of 2 pieces, top and bottom. The problem I have now, is the stresses are 2-3 times the expected stresses. I'm sure that what I'm doing wrong is simple, but I don't see it right now. I believe part of it is related to the two middle beams being so close together, but this is how the assembly is. Should I just drop one of the middle members?
                • Pressure Exerted on a weldment
                  Benjamin Reilly
                  I think I solved my own problem. First, I needed to make the pinball for calculating the joints big enough to absorb both center members together. Next, I needed to do my own wind pressure calcs... a coworker suggested that 90MPH was 33 PSF, instead of 21 PSF. Now my results look better, although there is still an anomaly in one of the trusses, probably joint related.