Part 19 - FEM-Analysis of a Column Crane with MEANS V10 · Part 19: FEM-Analysis of a Column Crane with MEANS V10 1 Part 19: FEM-Analysis of a Column Crane with MEANS V10 Column Crane

FEM-Analysis of a Column Crane

with FEM-System MEANS V10

Website: www.fem-infos.com

Email: [email protected]

Phone: 0049 - 7844 - 98 641

Part 19: FEM-Analysis of a Column Crane with MEANS V10 1

Part 19: FEM-Analysis of a Column Crane with MEANS V10

Column Crane Calculate the deformation, v.Mises stress, reaction force and the weight when the crane is loaded with its own weight and additional loaded of 1 ton weight load.

Start MEANS V10 by a double click on the desktop icon of MEANS V10. Select "New Project" and "3D tetrahedral mesh generation" to the CAD file select the 3D mesh generator.


3D Mesh Generator

Select the view bar icon and the drop-down-menu "3D Tetrahedral Mesh Generator":

A dialog box with the CAD formats appears:

STL is a flexible and common CAD format from the outer shell STEP is available at the time of default and in almost any 3D CAD IGES is one of the older CAD formats

also there are

DXF AutoCAD format for bar and line models, can imported in the Line Mode or in MEANS SHELL


It is not possible to mesh the CAD model following options are available:

• Check in the CAD system all solids and surfaces with unconnected edges and holes, very small extrusions or intersections and delete, optimize or repair them.

• If there is a assembly with many single parts then it must be united in the CAD system to create a complete model with only one part . For smaller assemblies use "FreeCAD" with menu "Create Step-Assembly".

• Convert with menu "SAT-STEP Converter" SAT files or other into the STEP or IGES format. The CAD Converter is a demo version with a long runtime of 60 days.

• Another way still to mesh the CAD model with the same CAD file would be optimized with various repair tools from HTA-Software. This service is under a support contract free of costs.


Mesh Generator No. 2 Select the STP file "Column-mounted slewing crene.stp" and select "Start Mesh Generator No. 2". It automatically starts the mesh generator and the CAD model is showing in a windows frame. You can rotate, scale and pan it with the three mouse buttons.

Generate a FEM Mesh Generate the FEM-Mesh with "Generate Mesh" with the default mesh density "moderate" to a FEM-Modell with 45 831 nodes and 148 187 tetrahedral elements.

Export FEM-Mesh with "test.fem"

Now select menu "File" and "Export Mesh" to export the mesh under the name “test.fem" in the directory path "Debug\Mesh". Now MEANS V10 starts automatically with the FEM model.

If the FEM mesh not automatically started with MEANS V10 then it can loaded as a structure file "test.fem" also from the mesh directory.


Create a Surface Model Choose menu „Generate Surface Model“ in order to create a surface model for selecting surfaces for loads and boundary conditions. Also you can show or hide the surfaces.

Select „moderate“ and create the surface model with 78 surfaces.


Create Load case 1 The crane is loaded with a weight load of 1 ton or 10 000 N plus dead weight. Load case 1 can be created either as a point load or as a surface load.

Point Load or Surface Load

Point Load

Select menu „Point Loads“ and menu „Step 2: Create Point Load“ and input the values:

Actual Load Case = 1 Number of Loads = 0 Load value = - 1, because number of loads is still unknown Direction = Z direction Selection: Surface Modus Select “Create Point Load” and double click on surface 19. This surface is displayed in the selectbox there choose “Create” to create a point load with 50 nodes.


Calculate the Load value

Select „Edit FEM Project“ and „Point Loads / Surface Loads“ and select menu „Load Factor”

and calculate the Load Factor with the difference of Weigh Load / Number of Loads

Load Factor = - 10 000 N / 50 = - 200 N


Input the Load Factor -200 with „replace“ and select „OK“.


Calculate Cross-Sectional Area Load case 1 may alternatively be generated with a surface load. Since only the weigh load is known must first be determined the cross-sectional area of surface 19 to calculate the value of the surface load.

Select menu „Surface Loads“ and „Step 2: Calculate Cross-Sectional Area“. In the new dialog box all surface areas are displayed and sorted by cross-sectional area. Select menu "Hide All Surfaces" and display only area of surface 19. Activate "Calculate Total Area…" and enter a total load of -10 000 N so a surface load of -0.5263 MPa is calculated.


Create a Surface Load

Select menu „Surface Loads“ and „Step 3: Create Surface Load“ and enter a surface load of “-0.5263” vertical to Surface.

Select „Create Surface Loads“ and double click to surface 19. Surface 19 is displayed in the select box, there choose “Create” to enter the surface load.


Create Own Weight Load

Select the icon menu and menu "Gravitation Loads" and enter Load Case 2 with a gravitational acceleration of "-9.81" in Z-direction.

After select "Create only Load Case (Quick solver)" because the FEM Solver combine both load cases automatically. In the Dr.Kühn solver, however, a load case superposition must be generated.


Create Boundary Conditions

The crane is clamped fixed on its column. Select menu "Create Boundary Conditions” and "Step 2: Create Boundary Conditions” and choose in the next dialog box “Create BCs” and double click on the surfaces 31 and 50.


Input Material Datas

Select the menu „Edit FEM Project“ and „Material Datas“ and input the material datas for steel.

Select “Material Date Base” and take up the material “steel” in the material data box.


FEM Analysis

First, save the FEM model under any name in the current project directory and select "FEM analysis" and again "FEM analysis". In the next dialog box, click on to the "Quicksolver" and "Step 1: Start FEM solver".

Select "Start FEM-Solver with INP-Interface" to close MEANS V10 automatically and to start the FEM Solver. After the calculation select "Start Postprocessing MEANS V10" to start MEANS V10 with the FEM model.


Postprocessing

Choose the menu „Postprocessing“ to evaluated the results.

v.Mises-Stresses

Please select following Settings:

• Results: Nodal or Element Stress Contour

• Load Case: 2

• Edit Accuracy: 4

• Result Component: von Mises Stress


Max. v.Mises-Stresses= 147.34 MPa

Increase accuracy

• Compare the results of the nodal stresses with the higher element stresses (see Handbook Part 2, Page 25)

• For a better result, use the TET4X8 element that can automatically divided the TET4 element into 8 smaller tedrahedrons so the FEM mesh is 8x finer and very fast.

TET4X8 is only available in MEANS V10. • Use the quadratic tetrahedral element TET10 with additional middle nodes

Runtime: 30 seconds 3 minutes 30 minutes


Displacements

Please select following Settings::

• Results: Nodal or Element Stress Contour

• Load Case: 1

• Edit Accuracy: 1

• Result Component: von Mises Stress

Max. Displacements in Z direction = -35.17 mm

Displacement Factor

• Select Structure with and without Displacements

• Calculate a Displacement Factor of 30.77

• Set down the Range of Values when you have high peak stresses

or abnormal stresses and deformations caused by badly tetrahedral elements.


Search Values Further select „Picking Stress Values” and define a value of “30” until a value of “40” with the unsigned and absolute values. Choose “Search” and click to the last value “-35.17” in the listbox to show the value directly on the displacement contour.


Check Sum of Reaction Forces

First select „Contour of Forces“ in z direction.

Contour of the Forces in z direction:


Select „Pick, Search and Save Values“ and “Sum of Forces” in order to show the

sum of all node forces and the sum only of the reaction forces in z direction.

Load Case 1: Sum of Reaction Forces in z direction = 10 000.6 N (= 1 ton)

Load Case 2: Sum of Reaction Forces in z direction = 13 614.54 N

Calculate Weight The weight can be calculated from the difference between the two load cases or run a new FEM analysis with only weight load by:

Weight load = 3614.54 N

Weight = 361.4 Kg

The crane has a weight of 361.4 Kg.

Documents

Part 19 - FEM-Analysis of a Column Crane with MEANS V10 · Part 19: FEM-Analysis of a Column Crane with MEANS V10 1 Part 19: FEM-Analysis of a Column Crane with MEANS V10 Column Crane