Our client asked us to work in partnership with them to design and build a full test rig for high cycle fatigue bend testing of varying sized carbon fiber pipe assemblies. We were presented with a mechanical concept drawing of a fatigue bend test rig, which required real time control of hydraulic servo actuators to produce complex pipe bend motions.
The challenge
The project called for the accurate position control of a pair of 1.75m long hydraulic cylinders to a position tolerance within 0.5mm. The application also required the monitoring of displacement forces applied to the pipe to automatically detect pipe yield failure. Data from position, force and pressure sensors was to be recorded and archived for the complete test cycle which might exceed 100,000 cycles per test.
Finally, the system had to be flexible enough to be adapted in the future to provide actuator force control rather than the position control initially required.
Our solution
Our technical experts worked closely with the customer to refine the test rig design concept before offering a control methodology which included optimized design of a multi-pump variable delivery hydraulic power pack. We specified a highly integrated solution which allowed users to upload bend test profiles prepared offline, to a custom graphical interface. The graphical interface allowed control of the power pack and servo actuators whilst reporting and recording all key system parameters in real time. The graphical interface also supplied extensive system diagnostics to present status and warning information of HPU equipment.
High accuracy performance of the system was ensured by allocating all real time control tasks to a stand-alone Programmable Automation Controller. All data collected during the test is exportable for subsequent analysis.
As the system employed high force to the test specimen, we supplied an integrated safety solution to guarantee safe access to the test cell area by safely removing all motive forces.
Key points
- The system was delivered on time and to budget, with no reliability issues recorded.
- Helipebs worked closely with the customer as a partner and technical expert to arrive at a technical solution that out-performed the original specification and best met their needs.
- The bespoke delivered solution encompassed many custom features identified by the customer during the development process and incorporated a wide variety of instrumentation.
- The hydraulic solution offered was designed to be highly efficient, minimizing power consumption requirements in the various operating modes.
- The customer has demonstrated the fatigue test system to many of their own clients who have also been highly impressed with the engineering and performance levels achieved.
