Piezoelectric force sensors are typically used to measure dynamic force events. Such sensors are divided into two main categories: load cells and impact hammers.
Piezoelectric load cells measure the amount of force transmitted through the sensor in response to an external stimulus, such as shaking or an impact.
Impact hammers allow you to apply an impact to a material and measure the actual amount of force applied. You can then correlate that force to the force measured by a load cell or to readings from accelerometers. Impact hammers can use tips of different size, shape, or material for measuring different frequencies.
Sensor manufacturers make load cells and impact hammers with varying sensitivity and other characteristics. Refer to the documentation from your sensor manufacturer for specifications and theory of operation for your load cell or impact hammer.