Strand7 Demonstration

Problem: We will draw the BMD, SFD, deflected shape of a simply supported beam with different types of load and combine them to create different load cases. Beam properties: Length 10m, x-section: 100mm width, 200mm depth, Elasticity modulus=2.0e11 N/m2, Poisson ratio=0.3 Loads: a. 10.0kN in the centre of the beam. b. 0.5 kN/m uniformly distributed load. Support conditions: Simply supported beam with one end pinned and one end roller support.

Step-by-step process are as follows: 1. Double click the Strand7 icon on the desktop.

You will find the starting toolbar of Strand7 as above.

2. Click new button. A new window will open up as follows. You will set up your units here. You need to be consistent with your units; else you will get incorrect results. Once you select your units, click OK.

Click File Save as. Give a meaningful name. We will save it as Tutorial 1. 3. We will create a beam. We can create it by two ways. You can create a point and extrude it, or you can create two points and connect it with beam element. We will follow the first method. To do this, click CreateNode.

We will create a point at origin. Accept the default values and press Apply. A node will be created and it will look like a yellow dot. 4. Now we will extrude it. Click ToolsExtrude by increment. Put 10.0 in the x direction.

Select the node you created. It will look like a pink dot. Click Apply.

A line and an additional node at the other end of the line will be created. Press F3 to make it visible in the middle of the screen. Close the dialog box (close the Extrude by Increment box). 5. Here you can see that only one element and two nodes are created. In order to get a good accuracy of the results and to remove error, we must divide the beam elements into several elements and nodes. The higher the number of elements the higher the accuracy, and at the same time the higher the time the computer processor will take to solve the problem. The number of elements is usually taken by trial and error and by judgement and it is called sensitivity study. Lets say we will divide the beam into 10 elements. This will be enough to get good accuracy. To do this, click ToolsSubdivide. Put 10 in A of the box.

The beam will be divided into 10 elements and 11 nodes.

6. We will create supports at the ends. Click AttributesRestraint. A dialog box will appear. To create a pin support at the left end, select all of the restraints except z-rotation. The dialog box will look like as follows.

Click the left end node to select it and click the Apply button in the dialog box. A cross will appear to ensure that restraint is activated on that node.

To create roller remove the x-translational in the dialog box. Click the right end and click the Apply button. It will look like follows.

You can notice the difference between pinned support and roller support. Save it. 7. We will create beam properties. To do this, click PropertiesBeam. A dialog box will appear as below. Select Beam in the Type area.

Click the Geometry tab.

Click Edit…. And then click the solid rectangle.

Click 0.1m in B and 0.2m in D.

Click Assign. A rectangular cross-section will be automatically created.

Click Structural tab. Put 2.0E11 in the Modulus and 0.3 in the Poisson. Click close.

The beam has its property.

8. Now we will apply load on the beam. Since there are three different types of load cases, we will create three load cases. To do this, click Global Load and Freedom Cases.

Load case 1 is already there.

Click New button once. It will create one more load cases.

You can edit the load case name and give them meaningful names by clicking the Edit Name button. Click OK.

To check that whether the load cases are created you can see it at the top-left corner of you working space.

Select the first load case (Centre load). This load case is activated. We will apply the load in the global Y direction. Click AttributesBeamPoint ForceGlobal.

Put -10000 N in the Y direction. Click Apply. The load will be applied. Close the dialog box.

We will now apply load for the second load case (Uniform load). To do this, click the drop-down box at the top left corner of the working space and change it to Uniform load.

Click AttributesBeamDistributed ForceGlobal.

A dialog box will appear. Select the whole beam. Select Dir Y, select PA from the drop-down list, and put -500 in PA text box. Click Apply.

0.5kN/m load acting downwards will be applied.

Save the model by clicking the Save button in the Toolbar. 9. The model is now ready. We will now solve it. This is a very simple model. We will use the Linear Static solver. To do this, click Solver Linear Static. In the dialog box check the Node Reaction in order to get reactions as well in the solution.

Accept the defaults. Click Solve. The model will start solving. If everything is right you will get no error messages. If you get error messages fix it and again solve it.

When there is no error, you are ready for result viewing. 10. Viewing of results; Click ResultsOpen Results File. In the dialog box, click the result file and click Open.

The file is now open. We will see the deflected shape.

Click the Displacement scale button in the Toolbar or from the ResultsDisplacement scale. Select a suitable scale. We will select 10%. Check the Add Undeformed button.

You can see the deflected shape.

We will now draw the BMD and SFD. Select the 0% in the displacement scale to make it undeformed shape.

First we will plot the BMD.

Click Result Settings button Results Settings).

from the Toolbar (or from the Results

In the dialog box that appears select Diagram then Force/Moment. Select Bending moment.

The bending moment diagram appears for the first case (Centre load).

For the other load case, select the Uniform load case from the Left drop-down list BMD for load case Uniform Load.

You can plot both the load case in the same screen. To do this, click ViewMulti View. In the dialog box put 2 in the X views. Check Multi Case. Click OK.

The plot will appear as follows. You can see different cases for the same variable to plot.

Remove the multi View and go back to the default single view.

We will now plot the SFD. Click the Result Settings Button. . In the dialog box select diagram, then Force/moment then check Shear Force. Remove the Bending Moment if it is checked. Click OK. Same way, you can view multiple cases of SFD in the same screen.

10. We can create a lot of load combinations from the existing load cases. We do not need to resolve model. Just create the combinations and open the results file, the load case combinations will be solved automatically. Suppose we will create three load combinations: a. Centre Load*1.0+Uniform Load*1.0 b. Centre Load*0.5 c. Centre Load*0.3+Uniform Load*0.8

To do this, close the results file by clicking Results Close Results File. Click ResultsLinear Load Case Combinations. In the dialog box click the Add button twice.

Put the factor according to the following figure in the same dialog box.

Press OK. To view the results of this combination, just open the file. Results Open Results File. Press Yes.

The results for the combination load cases are calculated.

You can see that three more load cases are added at the top-left corner.

View the results in Multi View or Single View as you wish. BMD

SFD