QC/T 1097-2018Bench test methods for fatigue life of front axle horizontal modules of passenger cars (English PDF)

4.1 General requirements

4.1.1 The horizontal module of the front axle shall meet the requirements of drawings and technical documents approved according to the prescribed procedures.

4.1.2 The installation state of the front axle horizontal module on the bench should be the same as that of the real vehicle (full load). During the test, attention should be paid to check to ensure that the test piece is in a normal installation state.

4.1.3 The accompanying test piece should be installed on the front sub-frame body according to the installation status of the real vehicle. When the accompanying test piece is abnormal, the accompanying test piece should be replaced. Then continue testing.

4.1.4 Allow cooling of non-metallic joints during loading.

4.1.5 The stiffness of the test tooling should meet the stiffness requirements not lower than that of the actual vehicle installation point.

4.1.6 It is allowed to use different equipment for testing, and the accuracy of the equipment is not less than 0.5% (full scale).

4.1.7 All tests need to use new samples, unless otherwise specified.

4.1.8 All test loads in this standard are sinusoidal waveforms of equal amplitude, as shown in Figure 1.

4.1.9 All calculated loads in this standard are allowed to be reserved to the single digit when loaded.

4.1.10 The test should be monitored and abnormal situations recorded. If cracks are observed in the test piece, the observation time, crack length and the degree and corresponding number of cycles are met, and the test is stopped when the failure criterion is reached.

4.1.11 Both the supplier and the buyer can agree on or adjust the test method of the product according to the characteristics of their own products.

4.2 Performance requirements

4.2.1 Test items

4.2.1.1 Longitudinal loading fatigue life test

Carry out the test according to 5.1, the test frequency is not less than 1.0Hz, and the loading times N is 300,000 times.

4.2.1.2 Lateral loading fatigue life test

Carry out the test according to 5.2, the test frequency is not less than 1.0Hz, and the loading times N is 200,000 times.

4.2.1.3 Fatigue life test of semi-loaded front axle horizontal module engine bracket

Carry out the test according to 5.3, the test frequency is not less than 1.0Hz, and the loading times N is 300,000 times.

4.2.1.4 Fatigue life test of engine front bracket of load-bearing front axle horizontal module

Carry out the test according to 5.4, the test frequency is not less than 1.0Hz, and the loading times N is 200,000 times.

4.2.1.5 Fatigue life test of load-bearing front axle horizontal module engine rear bracket

Carry out the test according to 5.5, the test frequency is not less than 1.0Hz, and the loading times N is 200,000 times.

4.2.1.6 Fatigue life test of the left and right brackets of the load-bearing front axle horizontal module engine

Carry out the test according to 5.6, the test frequency is not less than 1.0Hz, and the loading times N is 200,000 times.

4.2.1.7 Fatigue life test of stabilizer bar mounting bracket

Carry out the test according to 5.7, the test frequency is not less than 1.0Hz, and the loading times N is 200,000 times.

4.2.1.8 Fatigue life test of steering gear mounting bracket

Carry out the test according to 5.8, the test frequency is not less than 1.0Hz, and the loading times N is 200,000 times.

4.2.2 Failure criteria

4.2.2.1 The crack length measured along the crack propagation direction on the part surface is greater than or equal to 5mm or 2t (whichever is the smaller value, where t is the plate thickness).

4.2.2.2 The crack length measured along the direction of crack propagation at the weld is greater than or equal to 20mm or 20% of the weld length.

4.2.3 Evaluation indicators

The cycle life of the sample should meet the 95% reliability requirement at the 50% confidence level, and the selection of the number of samples can be found in Appendix A.

5.1 Longitudinal loading fatigue life test

5.1.1 Fix the body connection point of the front axle horizontal module to the stand.

5.1.2 The actuator and the control arm are hinged, the loading direction is along the X-axis direction, and both sides are loaded in the same direction, as shown in Figure 2 and Figure 3.

5.1.3 The test load and its calculation reference mass are calculated according to formula (1) and formula (2).

5.2 Lateral loading fatigue life test

5.2.1 Fix the body connection point of the front axle horizontal module to the stand.

5.2.2 The actuator is connected to the control arm, the loading direction is along the Y-axis direction, and one side is loaded, as shown in Figure 4 and Figure 5.

5.3 Fatigue life test of semi-loaded front axle horizontal module engine bracket

5.3.1 Fix the body connection point of the front axle horizontal module to the stand.

5.3.2 The actuator is connected to the engine bracket, and the loading direction is along the x-axis, as shown in Figure 6.

5.3.3 The test load is calculated according to formula (4).

5.4 Fatigue life test of load-bearing front axle horizontal module engine front bracket

5.4.1 Fix the body connection point of the front axle horizontal module to the stand.

5.4.2 The actuator is connected to the front bracket of the engine, and the loading direction is along the line connecting the engine installation point and the support point of the front bracket, as shown in Figure 7 and Figure 8.

5.4.3 The test load is calculated according to formula (5).

5.5 Fatigue life test of load-bearing front axle horizontal module engine rear bracket

5.5.1 Fix the body connection point of the front axle horizontal module to the stand.

5.5.2 The actuator is connected to the rear bracket of the engine, and the loading direction is along the line connecting the engine installation point and the support point of the rear bracket, as shown in Figure 9 and Figure 10.

5.6 The fatigue life test of the left and right brackets of the load-bearing front axle horizontal module engine

5.6.1 Fix the body connection point of the front axle horizontal module to the stand.

5.6.2 The actuator is connected to the left and right brackets of the engine respectively, and the loading direction is along the line connecting the engine installation point and the support points of the left and right brackets, as shown in Figure 11 and Figure 12.

5.6.3 The tests of the left and right brackets can be completed simultaneously or sequentially on the same front axle horizontal module sample.

5.7 Fatigue life test of stabilizer bar mounting bracket

5.7.1 Fix the body attachment point of the front axle horizontal module to the stand.

5.7.2 The actuator is connected to the mounting bracket of the stabilizer bar, the loading direction is along the Z-axis direction, and the two sides are reversely loaded, as shown in Figure 13-16.

5.8 Fatigue life test of steering gear mounting bracket

5.8.1 Fix the body attachment points of the front axle horizontal module to the stand.

5.8.2 The actuator is mirror-connected with the steering gear mounting bracket, the loading direction is along the Y axis, and both sides are loaded in the same direction, as shown in Figure 17 and Figure 18.

5.8.3 The test load is calculated according to formula (9).