Failure mechanism of rigid polyurethane foam under high temperature vibration condition by experimental and finite element method

Abstract

The failure mechanism of rigid polyurethane foam (RPUF) under room temperature (RT) and high temperature vibration conditions was investigated by experiment and finite element stimulation. Damaged RPUF specimens were prepared at different vibration amplitudes ranging from 0 to 19.879 mm at RT and 150 °C for different vibration times. The tensile test was utilized to evaluate the vibration damage degree of RPUFs, and the results exhibited that tensile strength decreased gradually with the increase of vibration amplitude and time at both RT and 150 °C. Thermogravimetric analysis and Fourier transform infrared spectroscopy illustrated that thermal degradation of RPUF is attributed to the decomposition of carbonyl urethane groups at 150 °C. The scanning electron microscopy analysis of the tensile fracture surfaces revealed that the vibration failure of RPUF mainly resulted from the existence of microcracks in cell structure. A finite element simulation was established by ABAQUS to study stress distribution of RPUF under different vibration loads, which then demonstrated that the microcracks are most likely to exist on the junction of two microcell units, which is due to convergence of stress in the process of vibration. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48343.

A Review of Research on the Effect of Temperature on the Properties of Polyurethane Foams

“…The shortening of the polyurethane foams chains resulted in a decrease in the glass transition temperature of the soft chain segments and promoted the crystallization of the soft chain segments during prolonged storage of the aged samples at room temperature. Wu [ 94 ] investigated the failure mechanism of RPUF at room temperature (RT) and high-temperature vibration conditions through experiments and finite element simulations. The results showed that the tensile strength of polyurethane foams gradually decreased with increasing high-temperature vibration and time, and the vibration damage of polyurethane foams was observed by microscopic experiments mainly due to the presence of microcracks in the cell structure.…”

Study of failure behaviors of rigid polyurethane foam treated under thermal and vibration conditions by experiment and numerical simulation

“…According to the previous experimental random vibration conditions, 11 the simulation was carried out under the random vibration mass block of 20 kg, root mean square acceleration of 8 g and the frequency ranges of 5-500, 500-1000 and 1000-1500 Hz, respectively. According to the previous studies, [17][18][19] the material properties of polyurethane matrix were assigned as follows: the density is 1180 kg m À3 (1.18 Â 10 À9 t mm À3 ), the yield strength is 37 MPa, Poisson's ratio is 0.4, the fracture toughness is 1.10 MPa m 0.5 (34.79 MPa mm 0.5 ) and the fracture energy is 5.08 mJ. The elastic modulus of polyurethane matrix can be calculated by Equation ( 1) according to the compressive elastic modulus calculation formula of closed cell foam proposed by Simone and Gibson.…”

“…In the previous studies, 11,16,17 the failure behaviors of RPUF treated under thermal and vibration conditions were studied, and the failure prediction RVE model had also been established, but the failure mechanism had not been further investigated. In fact, the previous failure studies of RPUF were always limited to the investigation on the failure behavior of RPUF, no matter under the conditions of high temperature or vibration.…”

Statistical Characteristics of Polymer Grouting Material Microstructure

“…erefore, the antidamage ability of the cell was enhanced and the compression strength finally increased. Wu and He et al [17,18] studied the failure of RPU foam under a high temperature and vibration, and the degree of damage after treatment was evaluated through its tensile properties. e results showed that the tensile strength decreases with the increase in vibration amplitude and time, and the vibration failure of RPU foam was mainly due to the existence of microcracks in the cell structure.…”

“…e objective magnification of SEM can be changed from 10 times to more than 300,000 times. It can be used to detect small structural characteristics of foam, such as structural defects that damage the foam of samples [17,18]. Computer image analysis method consists of image processing technology and image analysis technology [26].…”