Morphing, meshing, parametric studies, and selection of best material were made for the Z carred tool or the Z Desk. Morphing of models A-D was quieted. The longest to shortest motions for the most used functions were selected (A for Tool and B for Desk). All the models were meshed using a zero-density solid beam mesh (NoZ1), which led to the most changing mesh nodes as shown in the table below. The meshing time for the Z carred tool and the Z Desk was 4 hours and 24 minutes for model E. Model A has 26M nodes, B has 17.3M nodes, and C, D, and E have 4M nodes.
From the three selected model cases, E, B, and D were selected for FEA and fracture surface toughness because of the least change in material and design. Because of the hard rubber tires (84A) on model E, the element was replicated five times in the XY-Z planes for the FD model. Model B has softer urethane tires for enabling material deformation (85A hardness). In the fracture performance evaluation, model E achieved better results than model D for small SIFs and equivalent SIFs at fracture surfaces. The average deviation was about 2%. For the large SIFs and equivalent SIFs, a greater number of elements at the tip of the crack increased the accuracy of the simulation. The results for fracture surface toughness models from models B-D revealed the same trend as for models E-G, but these results are less accurate. The largest deviation was about 20%. These results confirm that there is no general trend because the choice of material. Model D had a marked difference in fracture surface performance.
CASE DESCRIPTION: Analyses of fatigue failures are reported with the aim of guiding manufacturers in preventing similar failures. The occurrence of fatigue fracture is commonly attributed to the propagation of a fatigue crack in a stressed material. 7211a4ac4a