# Modern Design of Carrier for Overhead Conveyor
## 2 Materials and Methods
### New Carrier
#### 2.3.1 Topology Optimization  
For the new carrier design, several topological optimizations were again performed. First, a topological optimization was made to a very generic carrier design, which basically satisfied only the necessary dimensions with respect to the size of the load. This was followed by a slightly more refined topological optimization, which has a shape already specified. The models of the topological optimizations are shown in Figure 18.  
From these optimized shapes, a new design was created in consultation with the company that applies the carrier. We came to the conclusion that for reasons of production technology and manufacturability with regard to cost, it would be ideal to design the new design from sheet metal, as opposed to the original design, which was from metallurgical blanks. It was also necessary to consider the material benefits, with the lowest weight being a carrier made from aluminum alloy. However, due to technology, it was decided that a steel alloy was more suitable. A design was created, and 5 pieces were produced. The prototypes were used to verify the price and take to verify the functionality and possible collisions with the track, for which there is no complete drawing documentation. The design that was selected about the technology and the company's requirements is shown on Figure 19.  
This design was excellent considering its weight, which was under 10 kg. However, during testing it became clear that it would be ideal to stiffen the carrier further. In addition, the reinforcements were positive for production purposes, as the reinforcements made the carrier easier to weld. The unresolved question is therefore whether the modified carrier, which was very similar in natural frequency to the unreinforced new design, but which had to be further modified and reinforced, would work.  
Figure 18: Topology optimization for new carrier.  
The result of these required modifications is shown on Figure 20. The carrier thus modified has a weight of 11.75 kg. The carrier was further subjected to strength calculations so that we could guarantee its proper function.  
The mass of the load has been replaced by a mass point at the centre of gravity of the load. The mass point was connected to the contact surfaces of the load and the carrier. The mass of the load is 35 kg. The plates have been replaced by surfaces with an associated material thickness. In space, the carrier is fixed again using the fixed support function in the upper eye of the carrier. The geometry with mass point and mesh is shown in Figure 21.  
The mesh element size was set to 5 mm. This size is sufficient for the needs of static structural analysis. Parameters of the mesh see on Table 2. The model was solved as a combination of shell and solid elements.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Elements** & **Number of Elements** \\ \hline TriShell3 & 584 \\ QuadShell4 & 39,539 \\ Hex20 & 528 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Mesh parameters of modified new carrier.  
Figure 19: New carrier.  
Figure 20: Modified new carrier.