Impact of Frequency of Load Changes in Fatigue Tests on the Temperature of the Modified Polymer

Abstract

In the article, the authors describe the analysis of the impact of the frequency of fatigue tests on the temperature of the modified polymer. The base material for producing the samples was the epoxy resin Epidian 57 cured with Z1 hardener. The presented study is part of a research program of adhesive joints made with the composition Epidian 57/Z1 aiming to determine the effect of physical modification of the adhesive composition on its properties and on the properties of adhesive joints made with such a modified composition. The tested adhesive compositions were modified by additions of micro-and nanoparticles in an amount of 1.85 % (micro-and nanoparticles) or 10 % (microparticles) in weight, depending on the type of the particles. In the studies, the authors used the particles of tungsten, microspheres and carbon nanotubes. The polymer samples produced by casting were loaded with compressive identical, one-sided loads at two different frequencies of load changes. During the tests, the authors recorded the temperature changes as a function of the number of cycles. The changes in the temperature field on the surface of the samples during the tests were observed by the infrared camera. As a result of the studies, it was possible to observe a significant impact of the composition of the polymer and the frequency of load changes during the test on the temperature of the sample.

Electrical response of carbon nanotube buckypaper sensor subjected to monotonic tension, cycle tension and temperature

“…However, the rate of resistance change is decreasing, it is because the fatigue failure of materials is closely related to inelastic responses such as plastic deformation, and plastic deformation is the most important form of inelastic response. The plastic deformation of materials under cyclic loading, the energy dissipation, that is, the cyclic hysteretic energy, is mostly released in the form of heat, and the temperature of the material increases continuously [32]. The increase of temperature has an effect on the resistance rate and the sensing performance of CNT BP sensor.…”

Bending Behaviour of Polymeric Materials Used on Biomechanics Orthodontic Appliances

“…Bending strength and flexural modulus are important features of medical devices made of PMMA. Many studies have evaluated these properties [11,66,67]. Based on the test results presented in this article, differences in bending strength were demonstrated.…”

Fatigue behaviour of adhesive bonds in tensile CFRP-metal double-strap joints with puddle iron plates taken from a 19th century bridge

“…--Where t a is the adhesive layer thickness; P min is the minimum load during fatigue test; P max is the maximum load during fatigue test; ΔP = P max -P min is the fatigue load range; Δσ s is the fatigue stress range in metal; R = P min /P max is the stress ratio; P max /P u,static is the load ratio (ratio between the maximum load during fatigue test and the average static bond strength of control specimens); N cycles is the number of load cycles; P u,fatigue is the residual static bond strength after 2 million fatigue cycles; P u,fatigue / P u,static is the residual strength ratio. During fatigue tests of adhesives at high loading frequencies, the temperature of the material usually shows a rising tendency, being this temperature rise higher as the frequency of load increases [25]. For this reason, the temperature in the joint during fatigue testing was registered using two thermocouples (one placed at each face of the specimen), positioned in contact with the CFRP laminate just in the joint centre (Fig.…”