Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Engineering
Eliminating Electromechanical Instability In Dielectric Elastomers By Employing Pre-Stretch, Liang Jiang, Tony Betts, David Kennedy, Stephen Jerrams
Eliminating Electromechanical Instability In Dielectric Elastomers By Employing Pre-Stretch, Liang Jiang, Tony Betts, David Kennedy, Stephen Jerrams
Articles
Electromechanical instability (EMI) is one of most common failure modes for dielectric elastomers (DEs). It has been reported that pre-stretching a DE sample can suppress EMI due to strain stiffening taking place for larger strains and a higher elastic modulus are achieved at high stretch ratios when a voltage is applied to the material. In this work, the influence of equi-biaxial stretch on DE secant modulus was studied using VHB 4910 and silicone rubber (SR) composites containing barium titanate (BaTiO3, BT) particles and also dopamine coated BT (DP-BT) particles. The investigation of equi-biaxial deformation and EMI failure for VHB 4910 …
Equi-Biaxial Fatigue Behaviour Of Magnetorheological Elastomers In Magnetic Fields, Yanfen Zhou, Mark Johnson, Shipeng Wen, Tony Betts, Stephen Jerrams
Equi-Biaxial Fatigue Behaviour Of Magnetorheological Elastomers In Magnetic Fields, Yanfen Zhou, Mark Johnson, Shipeng Wen, Tony Betts, Stephen Jerrams
Articles
The equi-biaxial fatigue behaviour of silicone based magnetorheological elastomers (MREs) in external magnetic fields was studied. Wöhler curves relating fatigue life to stress amplitude and dynamic stored energy for MREs with a range of magnetic particle contents were derived. It was found that the fatigue life of MREs in magnetic fields was higher than that without magnetic fields. Under constant stress amplitude conditions, the presence of magnetic fields resulted in longer times for the samples to undergo large deformations and thus complex modulus (E*) decreased at a slower rate during the fatigue process, especially for low stress amplitudes. MRE samples …
Equi-Biaxial Fatigue Testing Of Epm Utilising Bubble Inflation, Mark Johnson, Niall Murphy, Ray Ekins, John Hanley, Stephen Jerrams
Equi-Biaxial Fatigue Testing Of Epm Utilising Bubble Inflation, Mark Johnson, Niall Murphy, Ray Ekins, John Hanley, Stephen Jerrams
Articles
This paper describes an equi-biaxial tension fatigue test system which utilises the bubble inflation method to subject elastomers to equi-biaxial fatigue loading between user-defined limits of pressure, volume, stretch ratio or stress. The test system integrates a hydraulic inflation system, a high speed vision system and a control system. The high-speed vision system allows the stretch ratio and stress acting on the test specimen to be evaluated in real-time during testing. This in turn allows either stretch ratio or stress to be used as a direct control limit. In this research, constant maximum engineering stress control tests have been carried …