Abstract
The basis of shape memory alloys is the martensite – austenite transformation. For this transformation of the lattice structure the temperature change is one of the driving forces. In most cases electrical or thermal energy is used to activate the memory effect. In this paper, the tests and results regarding the required electrical energy to activate the memory effect will be described. If the shape memory wires work like actuators in automotive industry it is important to find the best values for the current intensity and the electrical tension. One of the questions of this investigation is to find the electrical value when the contraction and mechanical stress is constant. The defined goal is to obtain in less than one second 4-4,5% contraction at different stresses between 100-450 N/mm2 and to analyze the electrical behavior of the samples. A great focus was given to the electrical connection to realize the activation of the actuator wires. Different parallel and serial connections were investigated and the advantages and disadvantages of each installation will be presented in this paper. The final goal of this research is to find a matrix where it will be possible to choose the wire and the mechanical load and to read out the values for the electrical tension and the current intensity.
Keywords: NiTi wires, shape memory alloy, electrical energy