Standard Test Method for Measuring Forces During Dynamic Shearing of a Soft Projectile
This document describes a method for measuring transient forces generated by the impact of a soft or frangible projectile on a thin blade oriented in a plane parallel to the direction of the projectile motion. The document describes the hardware and instrumentation required as well as the processing and data reduction required to compute force.
In this test a projectile impacts a relatively thin, flat, blade-like object with a sharp leading edge. The direction of motion of the projectile is parallel to the plane of the slicer. The test is designed to mimimize lateral motion in the projectile as a result of the impact. The intended impact velocity range for this test is between approximately 50 m/sec and 300 m/sec.
The blade has a length greater than the largest diameter of the projecile and is supported on a fixture instrumented to measure force. The pojectile material is expected to be soft compared with the blade material. Impact stresses are expected to be small compared with the yield strength of the blade material so that all deformations in the blade are elastic.
The values stated in either SI units or inch-pound units are considered separate standards. The values stated in each system may not be exactly equivalent; therefore, each system must be considered as independent.
This standard does not address all of the safety concerns associated with its use. It is the responsibility of each user of this standard to ensure that any safety issues are properly addressed.
Rationale: Measurements of forced due to the dynamic slicing of soft projectiles can be difficult due to the very short time duration of the event and limitations on the dynamic response of standard transducers. This test provides a standard method for measuring these forces for comparison of one material to another. The method can be used to generate data useful in developing and validating computational material models for soft or frangible objects such as ice, soft polymers and materials used to simulate birds used for aircraft certification testing. The method can also be used to develop physical simulants for impact and ingestion certification testing for aircraft.