UNILAstic: Equipment and software to evaluate mechanical properties of materials by acoustic test

Resumo

The complete system consists of a support unit, a measurement unit and software. The equipment was
designed to perform non-destructive tests on small and medium cylindrical samples of different materials. The
support consists of a light but strong aluminum structure for the location of the sample to be tested. The measuring
unit consists of a microphone and a ball hammer. To perform the test, the sample is located in the support unit
where wires serve as support. With the ball hammer, the sample is hit several times and the sound is recorded with
the microphone. The UNILAstic software performs a vibration analysis based on samples of sound records to
establish mechanical properties of the materials (modulus of elasticity, poison ratio and shear modulus) based on
natural frequencies of the specimen (flexural, torsional and longitudinal frequencies). The UNILAstic software
was coded in MATLAB®. This article shows details of the construction of the support unit in order that it can be
replicated by anyone, in addition, the software features are presented showing its simplicity to obtain material
properties through some tests performed on concrete specimens. As a conclusion, the work presents an equipment
that can be replicated in a simple way and at very low cost in the universities of Brazil.