NED University Journal of Research
ISSN 2304-716X




PDMS MEMBRANE ANALYSIS FOR PIEZOELECTRIC MICROPUMP ACTUATION

Author(s): Muhammad Waseem Ashraf, Shahzadi Tayyaba, Muhammad Saleem Khan, Akhtar Hussain Jalbani, Saira Shaheen

Volume: Special Issue on MCCT'14

Pages: 69 - 78

Date: December 2014

Abstract:
Microelectromechanical systems (MEMS) based piezoelectric (PZT) micropump has been extensively used in medical field for last few years. PZT micropump exhibits high flow rate that is suitable for various medicinal applications. In this paper, the structural analysis of polydimethylsiloxane (PDMS) membrane has been presented that was performed using ANSYS software. Membrane is major part of piezoelectric micropump as it directly interacts with fluid and provides the force for required fluidic flow. ANSYS parametric design language (APDL) tool has been used for simulation and analysis. The PDMS membrane with length of 30000 m (9843 ft), width of 10000 m (3281 ft) and thickness of 500 m (1640 ft) to 3000 m (9843 ft) has been used for analysis. The pressure range of 1-4 kPa (0.15-0.58 psi) has been applied on membrane and the effects of stress and deflection have been observed at various thickness parameters. At applied pressure of 1 kPa (0.15 psi), the deflection of 0.053 m (0.17 ft) and the stress of 0.65 MPa (94 psi) have been observed. At applied pressure of 4 kPa (0.58 psi), total deflection of 0.211 m (0.7 ft) and stress of 2.62 MPa (380 psi) have been obtained. The effect of different thickness ranges on the uniform surface of membrane has been studied by applying the pressure. The stress and deflection variations due to thickness changes have been observed. At 250 m (820 ft) of membrane thickness, the net deflection is observed to be 1.2 m (3.9 ft). On the other hand, at 2000 m (6562 ft) thickness, the deflection decreases up to 0.0029 m (0.0095 ft). It has been observed that the maximum stress of 2.54 m (8.3 ft) and 0.128 m (0.42 ft) have been obtained at 250 m (820 ft) and 2000 m (6562 ft) thickness of membrane respectively. Thickness is most important parameters in micropump actuator and has direct impact of fluid flow through the micropump outlet. The deflection of membrane can be changed by changing its thickness. Hence micropump can be designed according to the desired requirement such as actuator performance and flow rate. This optimization of membrane can provide useful information to the researcher for fabrication of optimal design of micropump for specific biomedical application like drug delivery, fluid transport and blood transport.

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