Measurement system for Charpy impact test

Charpyjev udarni preizkus se izvaja z namenom določitve udarne žilavosti preizkušanca. Preizkus poteka tako, da Charpyjevo kladivo dvignemo v začetno lego in pustimo da zaniha. Na poti kladivo zadane ob preizkušanec in ga zlomi. Razlika med začetno in končno višino kladiva je vloženo delo za porušitev preizkušanca. Naprava je bila prvotno razvita z namenom preizkušanja kovinskih materialov, vendar se danes vse več uporablja tudi za umetne mase. V večini primerov se v praksi uporabljajo naprave z analognim prikazom rezultatov, ki zagotavljajo le omejeno ločljivost, nadomeščajo pa jih cenovno dražje naprave z digitalnim izpisom rezultata. V diplomski nalogi smo predstavili nov merilni sistem narejen na podlagi mikrokrmilnika za procesiranje informacij in dajalnika zasuka za merjenje kota, ki ga je moč pritrditi na napravo za Charpyjev preizkus. Zasnova merilnega sistema se je pričela z izdelavo prototipnega vezja, sledila je izdelava tiskanega vezja in na koncu postopek programiranja mikrokrmilnika. Rezultat je merilni sistem, ki izpisuje udarno delo z zadovoljivo točnostjo.The Charpy impact test is performed to determine the notch toughness. The test is carried out in such a way that the Charpy impact pendulum is lifted to the starting height and allowed to swing. On the way, the pendulum hits the specimen of material and breaks it. The difference between the initial and final height of the pendulum is the energy absorbed by the fracture event. The device was originally developed for the purpose of testing metal materials, but today it is increasingly used for plastics. In most cases devices with an analogue display of results are being used in practice, but they provide only limited resolution, that’s why they are being replaced by more expensive devices with digital output results. In this thesis, we introduced a new measurement system based on a microcontroller for information processing and a rotary encoder for measuring the angle. The measurement system can be attached to a Charpy impact test device. The design of the measuring system started with the production of a prototype circuit and was followed by the production of a printed circuit board. Finally, a microcontroller was programmed. The result is a measuring system that prints impact energy with satisfactory accuracy