Estimation of parameters of a three-layered sandwich beam

Abstract

In this work the physical parameters of a sandwich beam made with the association of hot rolled steel, polyurethane rigid foam, and high impact polystyrene, used for the assembly of household refrigerators and food freezers, are estimated using measured and numeric frequency response functions. The mathematical models are obtained using the finite element method and the Timoshenko beam theory. The physical parameters are estimated using the amplitude correlation coefficient and genetic algorithm methods. Initially, the experimental procedure to determine the material's mechanical properties, Young and shear moduli, and the density of the components of the sandwich beam is described. The elastic properties were obtained through tension and torsion tests. The shear modulus G c of the polyurethane rigid foam core was determined using a rectangular specimen and the Young's moduli of the steel and high impact polystyrene were determined using a conventional tension test. To estimate the dynamical values of the parameters in the frequency range from 10 to 400 Hz, separated dynamic sweeping tests were conducted using cantilevered beams of polyurethane rigid foam and high impact polystyrene. The experimental data from a three layered sandwich beam were obtained using an impact hammer and four accelerometers, displaced along the cantilevered beam sample. The parameters estimated are the Shear modulus and the loss factor of the polyurethane rigid foam, and the Young's modulus and the loss factor of the high impact polystyrene.

Young’s Modulus and Loss Factor Estimation of Sandwich Beam with Three Optimization Methods by FEM

“…Pritz [31] in the study of damping behavior of the solid material used for sound and vibration control verified that E, G and  are frequency dependents and  is more susceptible to frequency variation. Fact also observed by Barbieri et al [32] when evaluated statically and dynamically the parameters of one specimen made of the HIP and another the PRF in three frequency bands. Furthermore, the authors evaluated dynamically a sandwich beam excited by a mini shaker and the physical parameters of the HIP and PRF were estimated using the Timoshenko beam theory and two optimization methods: amplitude correlation coefficient (ACC) and GA, Table 3.…”

A review on recent advances in sandwich structures based on polyurethane foam cores

“…Dynamic loading has a serious impact on the overall service life of sandwich composites and must be paid serious attention. Researchers in previous years have used various experimental, numerical and mathematical modeling techniques to find the natural frequencies and study the dynamic behavior of flat and curved PUF sandwich composites . Baba and Thoppul investigated the dynamic behavior of flat and curved sandwich beams with debonding between the face sheets and the PUF core.…”

Evaluation of the dynamic properties of an aluminum syntactic foam core sandwich

“…During the study of a three-layered skin sandwich beam [38], used the damping ratio z to approximate the loss factor. They consider tan (d) ¼ z, where z is computed by …”