PSI - Issue 22

C.L. Niu et al. / Procedia Structural Integrity 22 (2019) 361–368 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

365

5

vertical load on the main structure of the frame is the load acting on the secondary empty spring seat. The fatigue load conditions of the frame are determined according to EN13749:2011 standard [13]. Thirteen fatigue conditions of the frame are selected. The load case descriptions are shown in Table 1.

Table 1 .Fatigue load Cases of Frame Name

Case

Load specification

备注

1

Vertical Dynamics + Lateral Dynamics

2

Vertical Dynamics + Lateral Dynamics

Three stages of loading, a total of 10 7 times. The first stage load is the original value. In the second stage, the load is amplified 1.2 times. The third stage load amplification is 1.4 times.

Vertical Dynamics+ Lateral Dynamics+Track Twisting5 ‰ Vertical Dynamics+ Lateral Dynamics+Track Twisting5 ‰

3

4

Fatigue load case of main structure of frame

5

Vertical quasi-static + Lateral quasi-static

6

Vertical quasi-static + Lateral quasi-static Vertical quasi-static + Lateral quasi-static + track twist 5 ‰ Vertical quasi-static + Lateral quasi-static + track twist 5 ‰

7

8

Fatigue load case of brake under vertical load Fatigue load case of brake longitudinal load Fatigue load case of brake clamp under inertial load Load fatigue load case of shock absorber

9

Vertical

2x10

6 times

10

longitudinal

2x10

6 times

11 12 13

Vertical, Lateral and longitudinal

10

7 times

10 7 times 10 7 times

Lateral and vertical loads Lateral and vertical loads

3.2 Selection of Key Assessment Welds Based on Structural Stress Method Structural stress method can effectively identify stress concentration. Because of the large number of welds on the welded frame, the information of weld seam in HyperMesh software and ANSYS calculation results are extracted. Using the program developed based on structural stress method, the key evaluation welds of the frame are screened, and 104 welds are analyzed under static load. The results of program analysis show that the stress concentration of six welded is obvious and belongs to the weak fatigue weld. The positions of these six welds are shown in Fig. 1.

weld 1

weld 2

weld 3

weld6

weld 5

weld 4

Fig. 1. Structural stress curve along weld and key assessment of weld location