Presentation on theme: "Using Start with a DXF file. Original drawing In Autocad drawing, create a new layer and using pdmode 35, pdsize 0.3 place points where you want a node."— Presentation transcript:
Using Start with a DXF file
Original drawing In Autocad drawing, create a new layer and using pdmode 35, pdsize 0.3 place points where you want a node. The size of the point (pdsize) may be changed to fit the drawings scale.
Nodes Nodes (= points) were added. Now turn off all layers except the new point layer.
Save as block Using the wblock command, save it as a drawing. Open the new drawing and connect each point with a line (=elements).
Connect nodes Then using dtext, add node labels including suffix which identifies nodes with external forces, supports etc., see manual.
Add labels Save the drawing as a DXF file and open Cofea. Use the Cofea File menu Input from DXF drawing and enter the Cofea File name and Title.
New file In this case the Cofea File name is H3 and default Title H3 hanger for electroplating
From DXF Then using the Cofea Command Input from DXF, insert the DXF file it into Cofea
that is, select a file and click O.K
Partial view of Cofea Input file Cofea version 14.0, inch hanger for porcelaine industry from DXF ================================================================== 0 MATERIALS : matype index : description des.press. des. temp. io ii k E cold Poisson Az Ay At E hot exp/con % Wz Wy Q weight1 weight2 Jz Jy K ================================================================== 26 NODES label x y z r e Before you can blink, all data for nodes and elements are created and also tables for supports and external nodes.
Adding data for material The Hanger is constructed from the above materials: Rod (Fig.1) and two rods welded together (Fig.2). The latter is inserted as a cross section (Fig.2) and longitudinal section (Fig.3) Properties of these sections have been calculated using Inertia program, and stored in files aRod.txt, Double.txt, DoubleY.txt. Fig. 1 Fig.2 Fig.3
The cross section (Fig.2) applies to beams 20-25, 30-35, , The longitudinal section (Fig.3) applies to columns and The remaining elements are made of a round bar, see Fig. 1 on previous slide.
Fillet weld is entered into joint properties The fillet weld is applied to the end nodes of elements (element 7), (element 26) and (element 16). The element numbers are as from the input table, see previous slides.
Data for all sections has been prepared using the Inertia program. Just select file and click O.K.
A partial view of a Cofea file after Material input Cofea version 14.0, inch hanger for porcelaine industry from DXF ================================================================== 3 MATERIALS : matype index : Description des. press. des. temp. io ii k E cold Poisson Az Ay At E hot exp/con % Wz Wy Q weight1 weight2 Jz Jy K Matl. 1 : 1 : Rod for hanger H e e e e e Matl. 2 : 1 : Double two rods welded together for hanger H e e e Matl. 3 : 1 : DoubleY two rods welded together as column for H e e ==================================================================
A partial view of a Cofea file after joint prop’s input ================================================================== 1 JOINT prop's (swap function 0 = no, 1 = larger SIF, 2 = swap) swap io ii k name Az Ay At Wz Wy Wt Jp# 1 : 1 : fillet weld 2/32" for hanger H3 reinforcement rods fw ================================================================== 6 JOINTS (location from node, to node) joint Jp# elmt loc label w w w w w w6 ****************************************************************** Now, when the most tedious and error prone work is done, we only have to specify the External forces and edit the Elements to show the selected material number and Welds to show the applicable element number. Now you are ready to RUN Cofea and review the output.
Cofea Control of Computation In this example of Cofea RUN, we requested a calculation to be processed for external loads and we requested a printout of global displacements, element stress and load summary. Complete input file, H3edited, is in the Cofea folder Examples.
Maximum stress table Output block: H3edited.cio Processed for: Ext.l. cold Header for stress: shear z' shear y' ten/comp element node bending z' bending y' torsion Rod Mohr lambda= Mohr Rod Mohr lambda= Mohr Rod Mohr lambda= Mohr Maximum resultant stress at element 15 node 100 Maximum longitudinal stress at element 15 node 100 Maximum tension 3102 at element 18 node 110 Maximum compression at element 23 node 105
Stress report Maximal resultant stress appeared to be located at node 100. Allowable stress for assumed steel A36 for this type of loading is psi. Therefore, the hanger as is, can not be certified for 160 #. Recommendation : increase the rod diameter from 0.5” to 9/16" while keeping the same geometry.