Cornering Fatigue Testing Machine
Introduction
The Conering Fatigue Testing (RFT) machine allows the simulation of an endurance fatigue test on car/light truck/bus wheels subjecting them to cornering fatigue stress and holding the test conditions constant throughout the test duration. This is the type of stress a wheel experiences during turning.
How it works
The Creative Dynamics Engineering’s cornering fatigue test machine performs testing on wheels, under rotating condition, with the bending moment applied at 90 degree to the test wheel.
The test machine is configured to test one wheel at a time. The machine contains load control and speed control servo loops. Applied load is controlled to +/- 1% of set point within stated load range. The servoloop is dynamic in that it will continuously compensate for load changes due to flexing of the wheel.
The operation and performance of the machine conforms to or exceeds the following international standards:
| 1. | ISO-3006 | Road vehicles – Passenger car wheels for road use – Test methods |
| 2. | ISO-3894 | Road vehicles – Wheels/rims for commercial vehicles – Test methods |
| 3. | SAE-J328a | Wheels – Passenger Car and Light Truck Performance Requirements and Test Procedures |
| 4. | SAE-J267a | Wheels/Rims – Trucks Test Procedures and Performance Requirements |
The deflection of the rod under load is also measured at two locations to provide deflection around 360°. The deflection signals the start of a crack at the disc wheel and therefore, is an important criterion for shut down of the test.
The servo loop can work in constant load mode or constant speed mode. In constant load mode the instantaneous bending moment measured is compared with the user supplied set point producing an error signal. This error signal id fed to the unbalance mass rotation drive which modifies the speed so as to bring this error signal within acceptable limits. The speed servo loop works in order to maintain a user supplied speed regardless of the resulting bending moment.
The function of the machine is to apply a rotating bending moment to the wheel; the resulting stresses on the wheel are very similar to the stresses created under cornering by a car or truck on the road. The Rotary fatigue test machine applies a force to the wheel central disc. The wheel failures on the machine will be to the center of the test wheel and or in the area of the wheel mounting holes.
The machine may be controlled in a manual or fully automatic mode (load, speed) by means of controls mounted on the front of the control panel. The following settings can be adjusted:
- No. of load cycles
- Bending moment or speed set point
- Percent value of increase in deflection for shut down criteria
- Maximum speed for shutdown criteria
- Maximum bending moment for shutdown criteria
- Information regarding the wheel under test
The following parameters are displayed on the front of the control panel:
- Applied Load (force / moment)
- Speed (moment RPM)
- Deflection
- Cycles (Total revolutions of wheel)
Machine Specifications
| Loading Method | Rotating Bending Moment |
| Table Height | 1,150 mm |
| Table Width | 1340 SQ mm |
| Work disc diameter | 1,200 mm |
| Disc diameter range | 12 – 22 inch |
| Disc width range | 3.5 – 14 inch |
| Length of bending shaft | 725 mm |
| Nominal bending moment | 25 kN.m |
| Test speed at the control of moment | 100 – 500 RPM |
| Test speed at the control of speed | 0 – 800 RPM |
| Load accuracy | < 1 % |
| Speed accuracy | < 0.5 % |
| Programmable Logic Controller | Siemens S7-300 |
| Touch screen HMI | 12 inch |
| Bending moment measurement | S-type Loadcell |
| Bending deflection measurement | LVDT |
| Drive servo motor | 5.7 kW |
| Electrical Power supply | 3 ∅, 380/220V, 50Hz, 8.0 kW |