Benchmark Testing and Evaluation, Fatigue Testing at Extreme High Temperature
Over the past 60 years DTB has developed extensive experience in fatigue testing. DTB has tested literally thousands of parts for military and commercial aircraft, tanks, trucks and automobiles. The demand for these services has come from the Army, Navy and Aircraft and Ground Vehicle Manufacturers.
Much of this testing has been to qualify parts supplied by alternate source manufacturers, using new manufacturing processes or different materials.
Aircraft Engine Fatigue Testing
Typically this testing is performed by subjecting previously qualified parts to load cycling or vibration testing. This testing of qualified parts provides a benchmark which is used to evaluate the alternate source parts.
An interesting part of this business has been the combination of fatigue testing and temperature extremes. This testing below has been performed for a major turbine engine manufacturer.
Combined Loads Testing at High Temperature
DTB has run a number of combined loads test programs. These tests were performed on various stator, compressor and turbine blades. These blades were fatigue tested at extreme temperatures from 400 to 1800 degrees F. These tests were conducted using a hydraulic actuator attached to the end of the blade using a clamp ring as shown below. The machines to run these tests were developed here at DTB. These were an improvement over the shaker based system used at the OEM since the test was controlled utilizing the actuators internal LVDT for displacement control.
Turbine Blade Fatigue Test Running at 1800° F
High Cycle Fatigue Testing at High Temperature
High cycle fatigue (HCF) testing is performed on a vibration shaker. This testing consists of mounting the base of the blade to a vibration plate and carefully tuning in the resonant frequency at the desired mode frequency and raising the amplitude to achieve the required stress levels. Calibration of the strain gages is critical for this test since the high strain levels quickly fatigue the strain gages. The entire test is then controlled based on the blade tip displacement. The HCF test is often required to run at elevated temperatures. This requires suspending the heaters above the shaker and cooling the vibration plate to protect the shaker head as shown below.
HCF Testing at 700 degrees F
Dayton. T Brown Inc. has the experience to assist our customers in qualification testing of any mechanical part in almost any environmental condition.