Issue 33

R. Sepe et alii, Frattura ed Integrità Strutturale, 33 (2015) 451-462; DOI: 10.3221/IGF-ESIS.33.50 458 S TATIC AND FATIGUE LOADING RESULTS AND DISCUSSION hree-dimensional finite element analyses have been carried out, based on the models and physical properties introduced above. Static analysis consisted of two stages, the initial concept design was analyzed in the first stage, then the structure was modified (the thickness of "C" or "double T" sections was changed from 2.5 mm to 3.0 mm) and simulated again under the same conditions in the second stage. As a result of the modifications, the roof module structure with better static strength properties was obtained (Tab. 6). The stress distributions and displacements were computed and analysed; details of the stress distributions of the modified roof module of some loading case will be shown. Fig. 10 and 11 show deflection (mm) in vertical (Z) direction and the von Mises stress due to loading case 2 for the modified freight car structure. The deformed shape is symmetrical with respect to transversal (YZ) plane. The maximum displacement (load case 2) is 0.3 mm on the transversal principal frames. Figure 10 : Deflection (mm) in (Z) direction due to loading case 2. Figure 11 : Von Mises stress (MPa) due to loading case 2. Fig. 12 and 13 show deflection in a vertical (Z) direction and the von Mises stress due to loading case 4. The maximum displacement (load case 4) in vertical (Z) direction is 2.1 mm on the PCM pipes. The deformed shape is symmetrical with respect to longitudinal (XZ) plane. Figure 12 : Deflection (mm) in (Z) direction due to loading case 4. Figure 13 : Von Mises stress (MPa) due to loading case 4. The maximum value (159.6 MPa) of the stress was found in the transversal frame at the intersection of an uprights frame. It is less than the allowable stress (173 MPa). Tab. 6 presents the maximum von Mises stress in the members of the roof structure, whereas maximum displacement are summarized in Tab. 7. All values of the modified structure are less than the allowable limits. T