QC/T 1096-2018Bench test methods for fatigue life of torsion beam rear axles of passenger cars (English PDF)

3.1 Test accompanied parts of torsion beam rear axle

Parts required to ensure that the torsion beam rear axle is installed on the bench, in the same state as on the actual vehicle.

4.2 Performance requirements

4.2.1 Test items

4.2.1.1 Fatigue life test under torsional loading

Carry out the test according to 5.1; the test frequency is not less than 1.0 Hz; the number of loading N is 300000.

4.2.1.2 Fatigue life test under lateral loading

Carry out the test according to 5.2; the test frequency is not less than 1.0 Hz; the number of loading N is 200000.

4.2.1.3 Fatigue life test under longitudinal loading

Carry out the test according to 5.3; the test frequency is not less than 1.0 Hz; the number of loading N is 300000.

4.2.1.4 Fatigue life test of spring disk

Carry out the test according to 5.4; the test frequency is not less than 1.0 Hz; the number of loading N is 300000.

4.2.1.5 Fatigue life test of shock absorber bracket

Carry out the test according to 5.5; the test frequency is not less than 1.0 Hz; the number of loading N is 300000.

4.2.2 Failure criteria

4.2.2.1 The crack length, which is measured along the crack propagation direction on the part surface, is equal to 10 mm.

4.2.2.2 The crack length, which is measured along the crack propagation direction at the weld, is greater than or equal to 20 mm or 20% of the weld length (whichever is smaller).

4.2.3 Evaluation indicators

The cycle life of the specimen shall meet the 95% reliability requirement, at the 50% confidence level. See Appendix A for the selection of the number of specimens.

5.1 Fatigue life test under torsional loading

5.1.1 Fix the connection point of the body of the torsion beam rear axle to the bench, by means of hinged joints. The spring, as test accompanied part, shall be installed on the spring plate, according to the requirements of 4.1.3.

5.1.2 The loading point is located at the intersection of the wheel axis and the wheel installation end surface on the trailing arm; the loading direction is along the Z-axis direction; the two sides are reversely loaded, as shown in Figures 2 ~ 4.

5.1.3 Test load and calculation reference mass are calculated, according to formula (1) and formula (2):

Where: S - Torsional loading stroke, mm;

n - Number of seats;

M - Reference mass for test load calculation, kg;

L - Wheelbase, mm;

B - Rear tread, mm.

Where: MCurb - Curb weight of automobile, kg.