resistance spot welding is an important manufacturing process in the automotive industry for assembling bodies. the quality and strength of the welds and, by extension, the body is mainly defined by the quality of the weld nuggets. the most effective parameters in this process are sheet material, geometry of electrodes, electrode force, current intensity, welding time and sheet thickness. the p...

This paper presents an analytical solution for response of a piezoelectric hollow cylinder under two-dimensional electro thermo mechanical fields. The solution is based on a direct method and the Navier equations were solved using the complex Fourier series. The advantage of this method is its generality and from mathematical point of view, any type of the thermo mechanical and electrical bound...

electro-thermo-elastic stress analysis of piezoelectric polymeric thick-walled cylinder reinforced by boronnitride nanotubes (bnnts) subjected to electro-thermo-mechanical fields is presented in this article. the electro-thermo-elastic properties of piezoelectric fiber reinforced composite (pefrc) was studied by a modified xy micromechanical model capable of exhibiting full coupling relation be...

We present a combination of transient electro-thermal simulations of three-dimensional interconnect structures and the calculation of their coupled intrinsic thermo-mechanical stress distributions. For the numerical solution of the electro-thermal as well as the thermo-mechanical stress problem, we apply the finite element method. A practical example is presented where the temperature and the p...

One of the most challenging tasks while designing an automotive electronic device is to take into account its whole electro-mechanic environment, so that time expensive failure tests can be reduced. We show a case study, developed in collaboration with an industrial partner, in which an automotive Compact Disk (CD) player is modelled. Using VHDL-AMS, not only its whole mixed-signal electro-mech...

Electro-magnetic forces provide a potentially power full means in designing dynamic experiments with active control of the loading conditions. This article deals with the development of computational models to simulate the thermo-mechanical response of electro-magnetically loaded metallic structures. The model assumes linear electromagnetic constitutive equations and time-independent electric i...

The lifetime of micro electro–thermo–mechanical actuators with complex electro–thermo–mechanical coupling mechanisms can be decreased significantly due to unexpected failure events. Even more serious is the fact that various failures are tightly coupled due to micro-size and multi-physics effects. Interrelation between performance and potential failures should be established to predict reliabil...

In this paper, the general case of an anisotropic thermo-electro elastic body subjected to static biasing fields is considered. The biasing fields may be introduced by heat flux, body forces, external surface tractions, and electric fields. By introducing proper thermodynamic functions and employing variational principle for a thermo-electro elastic body, the nonlinear constitutive relations an...

We report time domain observations of optical instability in high Q silicon nitride whispering gallery disk resonators. At low laser power the transmitted optical power through the disk looks chaotic. At higher power, the optical output settles into a stable self-pulsing regime with periodicity ranging from hundreds of milliseconds to hundreds of seconds. This phenomenon is explained by the int...