20Khz implements materials fatigue testing Ultrasonic fatigue
The fatigue testing machine is used to measure the fatigue
characteristics, fatigue life, pre-cracking and crack propagation
test of tensile, compressive or tensile-pressure alternating loads
of metals, alloy materials and their components at room
temperature. While demanding high performance, people are
increasingly demanding working conditions for structures and parts,
and fatigue research has not been satisfied with life spans of tens
of thousands of times.
Ultrasonic fatigue is caused by acoustic, aerodynamic or mechanical
operation. Its high frequency, small amplitude, high cycle time but
short duration can lead to fracture damage of aviation, spacecraft
and other mechanical structures. The fatigue testing machine has
various forms due to the structure of the load, and the ultrasonic
fatigue testing machine is mainly used for the tensile compression
Ultrasonic virbrate 20000 time in 1 second, for some aerospace
material , it need fatigue test at million times, if test it by human, it needs about 20years. but by
ultrasonic, it need only minutes. By our special desgin ,the output
of the horn will be enlarge times, so the strength will not less than the human test
Ultrasonic fatigue strength test, where it had been difImplements
materials fatigue testing at 20 kHz. Consequently, it is possible
to evaluate ficult to obtain data before. Also, data for 107 cycles
can be obtained in about ten minutes.
The ultrasonic fatigue testing system presented here gives the
opportunity of evaluating the fatigue lifetime curve, the cyclic
stress-strain curve, the course of the plastic strain amplitude
versus the number of loading cycles, the fatigue lifetime curves in
Manson and Coffin representation, factors of a new fatigue lifetime
curve etc, for different metals. The full complex data are shown
for carbon steel.
20 kHz ±500 Hz (recommended test range 20 kHz ±30 KHz) * The test
frequency is determined by the resonance
frequency of the specimen.
|Horn end face amplitude||±10 to ±50 µm|
|Test stress range|
Stress when the specimen undergoes ±10 to ±50 µm
displacement *The stress value depends on the specimen
shape and physical properties.
|Power requirements||200 V 3-phase: 2 kVA (air compressor)|
200 V 1-phase: 3.5 kVA (ultrasonic fatigue testing system)
100 V 1-phase: 1 kVA (including PC, displacement recorder, air
- Accelerated evaluation of the fatigue life of metals and materials
is possible at 20 kHz cycle speed. Even 1010 cycle tests are completed in a mere six days.
- Significant stress can be produced by testing under resonance
conditions, and furthermore is economical.
- Constant stress amplitude control is possible via the controller
(provided) with the PC.
- Optimal for long-life evaluation of materials and high-speed
vibration replication experiments.
- The test system is extremely compact, allowing it to be installed
- The Windows software provided can be used for easy testing from
design of resonance specimens through to actual testing.
Ultrasonic fatigue test method is mainly used in aerospace,
high-speed rail vehicles and nuclear power plants, and carries out
(super) high-cycle fatigue performance tests of various metal
materials such as alloy steel, aluminum alloy and titanium alloy,
and carbon fiber composite materials. Compared with the
conventional fatigue test method, the test time can be shortened by
more than 90%, and the test cost is greatly saved.
The recently increased interest in very high cycle fatigue
properties of materials has led to extended use and further
development of the ultrasonic fatigue testing technique. Specimens
are stimulated to resonance vibrations at ultrasonic frequency,
where the high frequency allows collecting lifetime data of up to
1010 cycles and measuring crack propagation rates down to 10−12 m
per cycle within reasonable testing times. New capabilities and
methods of ultrasonic testing and outstanding results obtained
since the year 1999 are reviewed. Ultrasonic tests at load ratios
other than R = −1, variable amplitude tests, cyclic torsion tests
and methods for in situ observation of fatigue damage are
described. Advances in testing at very high temperatures or in
corrosive environments and experiments with other than bulk
metallic materials are summarized. Fundamental studies with copper
and duplex steel became possible and allowed new insights into the
process of very high cycle fatigue damage. Higher cyclic strength
of mild steels measured at ultrasonic frequency because of plastic
strain rate effects are described. High‐strength steels and
high‐alloy steels are less prone to frequency influences.
Environmental effects that can lead to prolonged lifetimes in some
aluminium alloys and possible frequency effects in titanium and
nickel and their alloys are reviewed.