Strength assessment of waste containers and max. allowable load calculation
3D CAD models were provided by the Customer as well as a scheme of boundary conditions which were adopted in accordance with conditions of loading-unloading of waste containers on a car platform. Strength is going to be checked for all positions of the waste container (Figure 3):
Project of strength assessment of waste containers consisted of a few tasks:
Waste containter is a steel structure consisted from stiff plates with reinforced elements (e.g. knees, brackets, rectangular tubes etc.).
FEA Engineering was asked to check two design of waste containers. Both designs are simillar except of hooklift assembly which is different. General overview of both containers can be seen in Figures 1 and 2.
According to the terms of reference, the elements of the tractor, rollers, door hinges and lifting brackets are of particular interest. To obtain stress distribution in waste container structures, finite element models (FEM) were prepared. PLATE elements with a size of 10-50 mm were used for stiff panels. The elements of the rollers, loops, as well as the rod of the hooklift device were modeled with linear and parabolic SOLID elements. Sizes of the elements were selected based on the conditions for ensuring sufficient accuracy of the calculation results.
The connection of structural parts in the model was carried out using the GLUE option, and the contact interaction properties with a friction coefficient of 0.2 were set in the connection of the roller and loop parts.
FEM general overview are shown in Figures 4 and 5.
Figure 1. Waste container (design #1).
Figure 2. Waste container (design #2).
Figure 4. FEA model of the waste container (design #1).
Figure 6. Von Mises stress distribution results
in the hooklift device (design #1).
Figure 7. Von Mises stress distribution results
in the hooklift device (design #2).
Figure 3. Container positions in case of unloading and installation back on the vehicle platform.
Figure 5. FEA model of the waste container (design #2).
Stress distribution and safety factors were determind for max. load and nominal work conditions. Equivalent Von Mises stress distribution on waste containers can be seen in Figures 6 - 9.
Figure 9. Von Mises stress distribution results
in the container bottom plate (design #2).
Figure 8. Von Mises stress distribution results
in the container bottom plate (design #1).