D. BALAJI, P. GOVINDARAJAN, J. VENKATESAN: Experimental
investigation of single cylinder four stroke SI Bajaj engine using
denatured spirit 85 as alternative fuel 1
U. BERARDI: Characterization of an electro-active polymer actuator
for vibration control 13
J. MURåN, V. KUTI: An effective thermo-elastic composite (FGMs)
multilayered beam finite element 33
D. BALAJI, P. GOVINDARAJAN, J. VENKATESAN
The objective of this study is to investigate the effect of using DNS85 (ethanol 79.3% + water 5.7% + gasoline 15%) as fuel in a four cylinder four stroke SI engine. In the process of investigation, the performance tests were conducted on the engine to analyse volumetric efficiency, brake thermal efficiency, brake power, engine torque and brake specific fuel consumption. Exhaust emissions were also investigated for carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx) and carbon dioxide (CO2). Experiments were conducted at 50% throttle opening position at different engine speed ranging between 2500 to 4500 rpm. The results of the experiments revealed that blending the unleaded gasoline with denatured spirit increases the brake thermal efficiency, volumetric efficiency, brake power, engine torque and brake specific fuel consumption. The CO, HC, NOx and CO2 emissions in the exhaust decreased. The DNS85 as fuel produced the encouraging results in engine performance and reduced exhaust emissions for all the tested speeds and measured performance parameters.
Tuned vibration absorbers are really effective only at the tuned frequency, as they act as notch filters for the vibration excitation. This limit is overcome by adaptive tuned vibration absorbers (ATVAs), which offer the possibility to adjust their behaviour according to needs. The paper focuses on a smart device for vibration control made up by an electro-active polymer (EAP). The EAP was obtained by constraining a silicone sheet between two silver layers: for this it is also known as dielectric electro-active polymer (DEAP). DEAP can achieve large deformation (> 100% strain) while sustaining large forces. For this behaviour, they are promising materials for light weight and energy efficient pumping systems or isolation actuators. The paper reports the dynamic characterization of an actuator. A modal test of the actuator was performed driving it with an electrodynamic shaker, supplying a voltage from 0 to 2.7 kV, and acquiring the FRFs in the frequency range from 0 to 1 kHz. A good agreement between theoretical and experimental data was obtained by using a multi-element model of the actuator. Stiffness and damping laws of the actuator were finally determined by a comparison between the theoretical model and experimental results for different frequencies. Some considerations regarding the use of the DEAP actuator for vibration control of harmonic excitation are included. The addition of a linearizing gain schedule to the DC voltage bias showed reducing the unwanted effects of harmonics.
J. MURåN, V. KUTI
The theoretical part of this contribution deals with deriving the effective matrices of the thermo-elastic composite symmetric multilayered sandwich finite element with a constant cross-section (which is predominantly rectangular) with spatial variation of the effective material properties. This variation of effective material properties is caused by both continuous longitudinal and layer-wise symmetric transversal variation of the constituent's volume fractions and constituent's material properties. The theoretical part of this contribution is completed by numerical validation, which documents the high accuracy and effectiveness of our proposed thermal-structural composite (FGMs) link/beam finite element.