Effect of the multiple damages and temperature changes on the natural frequency

Damage detection based on structural dynamic characteristics, such as natural frequencies
and mode shapes, is an important area of research. Obtaining accurate structural dynamic
characteristics is perhaps the most challenging aspect. In particular, changes in environmental
temperature due to seasonal weather or radiation from sunshine leads to changes
in the dynamic characteristics of structures. An important conclusion is that changes in
the dynamic characteristics of a structure due to damage may be smaller than changes in
the dynamic characteristics due to variations in temperature. Also, damage can affect the
frequency response. This is the first study of evaluation of the effect of changes in temperature
and multiple damages on natural frequency at the same time. In this paper, the
simultaneous effect of the multiple defects and temperature on the natural frequencies of
6063 aluminum alloy beam are assessed numerically. ABAQUS finite element software is
used for the numerical analysis. The present paper aims to evaluate the temperature effect
and multiple damages on vibration responses. The variations in the frequency have been
analysed in simulation by using an aluminum specimen and obtaining impedance signatures
at temperatures ranging from −200◦C to 204◦C. The results show that an increase in
temperature leads to a decrease in structural frequency, and that a decrease in temperature
leads to an increase in structural frequency. The evaluation of the effect of multiple
defects on natural frequency shows that when damages are created in the structure, there is
a significant decrease in the natural frequency responses of the 6063 aluminum alloy beam.
The results show that damage causes a decrease in the natural frequency of the structure.
This study highlights the importance of applying simulation methods to the evaluation of
the effect of changes in environmental temperature and multiple damages on the dynamic
characteristics such as natural frequencies and mode shapes, especially at the same time.