The invention of the first smart impact hammer provides new ways of mechanical excitation for structural dynamic applications. Smart means that the device processes its signals internally. The modal hammer WaveHitMAX guarantees fully automatic, reproducible and high-precision excitation of the test object without double hits. The user can set the number of hits, impact force and the delay between hits accounting for different degrees of damping / delay times. All presettings like zero point or impact force search are made automatically by the hammer. Manual adjustment by the user is no longer necessary.
WaveHitMAX has new features compared to semi-automatic impact hammers. The advantages of internal signal processing are:
The WaveHitMAX can be operated quickly and easily by the included software on a Windows enabled device (PC or tablet) through the Ethernet.
Additional signal output for various applications.
In addition to the features of the new MK1, the WaveHitMax MK2 offers the option of direct voltage output of the force sensor.
The type of signal output can be selected in the new MK2. In addition to the existing internal signal processing and analysing, the direct output of the force sensor's can be selected at the signal output. This feature provides following advantages:
It is the tool of choice for:
We guarantee a fully automatic, reproducible and highly precise excitation free of any bouncing and annoying parameter adjustments or tunings. This smart device called WaveHitMAX does these adjustments for you just automatically.
The user has several options to control the WaveHitMAX. Depending on whether he wants to operate it connected to a computer or completely autonomous, both is possible.
There are five different tips for the hammer. The tips are made of different materials and have different hardnesses. They influence the excited frequency range accordingly. You can find the exact correlation on our technical page.
There are also four different additional masses. These are used to apply additional force.
On the back panel of the WaveHitMAX are all necessary plugs and connectors. Among others:
Depending on the excitation force, a different force sensor must be used. They cover different force ranges.
| SENSOR SPECIFICATION | ||
|---|---|---|
| Available ICP® force sensors | ICP® force sensor – 445 N | ICP® force sensor – 2224 N |
| Impact force2 | 15 – 450 N | 20 – 2200 N |
Sensitivity | 20 mN/V 11.24 mV | 4 mV/N 2.24 mV/N |
| Impact pulse width3 | ≥ 0.80 ms | ≥ 0.80 ms |
| Linearity error | < 1 % | < 1 % |
2 Determined for the best possible test object and mounting.
3 The pulse width depends on the combination of the selected impact force, the instrumented impact tip and the physical properties of the test object.
| BNC output | MK1 ± 10 V, noise floor < 100 mV (1 %) | MK2 |
| Impact interval1 | 600 ms – 1 h | |
| No. of hits | 1 – 1.000.000 or start/stop mode | |
| Operation | via LED display on device or WaveHit GUI | |
| Impact release | via trigger, WaveHit GUI | |
| Attachment | Fastening via prism rail / prism clamp, optional accessories | |
| Connections | Ethernet, trigger, integrated power supply, 240 V AC, signal out | |
1The range is limited by the width of the LED display. Usable range larger when using GUI.
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In this video, we are introducing the WaveHitMAX by gfai tech GmbH. The invention of the first smart impulse hammer provides new possibilities of mechanical excitation in structural dynamic applications. The WaveHitMAX guarantees a fully automatic, reproducible and high precision excitation of a test object without any double hits.
Software
Use the WaveHitMAX within your software. The WaveHit API (Application Programming Interface) for C++ helps you to integrate the full range of functions into your own application with little effort. A MATLAB® interface is coming soon.
Hardware
Use the WaveHitMAX together with your automation technology. The impulse hammer can be triggered directly via photoelectric sensors or controlled via programmable logic control.
All presettings like zero point or impact force search are made automatically by the hammer. This makes it the first smart device of structural dynamics.
We guarantee a single hit excitation in almost all environments, positions and materials.
The WaveHitMAX finds its excitation point and its excitation force automatically.
If the test object is on a moving base like a production line or if it has simply been moved by accident, the WaveHitMAX can easily compensate for this.
For a correct excitation, the following must be ensured:
A correct excitation should have the following course over the frequency range to be examined:
The general idea is that resonant frequencies can be more easily identified by applying the same force level over the entire frequency range.
The width of the input force is controlled by the duration of the shock pulse. However, the shorter the duration of the impulse, the wider the frequency range response.
To controll the input force frequency range, you can change the hammer tip in two ways:
A hard tip has a very short pulse and excites a wide range of frequencies. Whereas a soft tip has a long pulse and excites a narrow frequency range. But the hammer tip itself does not completely determine the excited frequency range. The local flexibility of the structure must also be taken into account.
Generally applies: The lighter the hammer and the stiffer the tip, the higher the excited frequency range.
Choice of tips:
A double hit excitation can often be detected in the time domain as well as in the frequency domain.
If a second peak occurs in the time domain, this is an obvious evidence for a double hit excitation.
If this is not the case, it is possible that the second peak is just too small or too close to the first peak. In this case, the double hit excitation can be detected in the frequency domain.
It shows one of the following significant forms:
The effect of the double excitation can be calculated from the time interval between the two impacts.
The following chart shows how the inverse of the time interval affects the interference in the frequency band.
Concept and technical implementation in cooperation with:
Ingenieurbüro Andreas Lemke
