SRI KALAHASTEESWARA INSTITUTE OF TECHNOLOGY SKIT Road, Panagal, SRIKALAHASTI -517640, Chittoor Dist

(Approved by A.I.C.T.E., New Delhi & Affiliated to JNTU, Anantapur)

Department Of Mechanical Engineering,

Project on ANALYTICAL AND SIMULATION ANALYSIS OF C-SECTION MICRO CANTILEVERS USED IN MEMS APPLICATIONS , under the guidance of Sri. C.VIJAYA BHASKAR REDDY

M.Tech,; M.I.S.T.E,; (Ph.D),Assistant Professor (Sr)

C.RAJA SEKHAR 08381A0339 S.RADHA KRISHNA 08381A0338 G.V.R.TEJA 08381A0356 R.ADITYA 08381A0301 V.NITHIN KRISHNA 08381A0333

BY

Acknowledgements• We are very thankful to Our beloved Principal and HOD of

Mechanical Engg Dr.B.Jayachandraiah Garu for giving us the opportunity to do our main project

• We are also thankful to our Incharge HOD Sri.C.Bhaskar Reddy for giving us permission in doing the project

• We express our gratitude to our Guide Sri.C.Vijaya Bhaskar Reddy for encouraging and giving timely suggestion in completing the project.

• We are thankful to our Non Teaching staff of mechanical department for their co-operation during the project work.

• We dedicates this work to our Parents and teachers who imparted the knowledge.

Aim of the Project

• Micro cantilevers are the most simplified MEMS based devices

• The overall sensitivity of micro cantilever depends on both the deflection and stress of the cantilever

• The stress and deflection is being found by Stoney equation analytically and simulated in ansys software

• values are being compared and the errors are being found.

INTRODUCTION

• A micro cantilever is a device that can act as a physical, chemical or biological sensor by detecting changes in cantilever bending or vibrational frequency. The polymer su8 is used in this project

• Micro cantilevers are a million times smaller than the diving board having dimensions in microns (Micro= 10-6

m)

APPLICATIONS

• In Micro Electro Mechanical Systems (MEMS)

• Temperature Sensors / Heat Sensors

• Viscosity Sensors

• In physical, chemical and biological sensing

Literature Review

• Christiane Ziegler, (2004) explains about the cantilevers based bio-sensors. He explains mainly about the theory of cantilevers biosensors. The most common method to measure the deflection of a cantilever is the optical lever technique

• Mo Yang et al, (2003) describes about the High sensitivity piezoresistive cantilever design and optimization for analyte-receptor binding.

• Mohd. Zahid Ansari et al(2008) explains about the Study on Increasing Sensitivity of RectangularMicrocantilevers Used in Biosensors. He calculated the deflections using Stoney equation

Materials and Methods ANALYTICAL ANALYSIS

• Stoney equation is the main basis for the calculation of deflection in micro cantilevers

• The Stoney equation used for the calculation of deflection is [Mohd. Zahid Ansari et al(2008) ]

Mathematical Analysis Model Case-1:

polymer - su8Pressure = 0.01 N/mm2

Surface stress ( ) = 0.8 N/m𝜎Elastic Modulus (E) = 5GpaPoisson ratio (v) = 0.22Length (l) = 200µmWidth (w) = 120µmThickness (t) = 2.8µmArea (a) = 17600µm2

•

= 0.37µm

Deflection (Z) =0.37µm

IN SIMILAR WAY THE DEFLECTION IS BEING FOUND FOR DIFFERENT VALUES OF STRESS

SIMULATION ANALYSIS

• The software used for the analysis of deflections in cantilevers is “ANSYS”.

• ANSYS is general-purpose finite element analysis (FEA) software package.

• This type of analysis is typically used for the design and optimization of a system for too complex to analyze by hand

CREATING NODES

PLANE FORMATION

AFTER EXTRUSION

AFTER MESHING

• By using Ansys the deflections have been found for different values of Surface stress

• Case 1:

DMX= 0.479E-06

AFTER APPLYING LOADS

Case-2: Case-3:

Case-4:

VON MISES STRESS

DMX=.766E-06SMN=58904SMX=.912E+07

STRESS INTENSITY

DMX=.766E-06SMN=57359SMX=.105E+08

ResultsPressure (p)

N/mm2

Surface Stress(∆σ)

N/m

Simulation

deflection(µm)

Analytical

Deflection(µm)

Error (µm)

0.01 0.8 0.42 0.37 0.05

0.012 1.05 0.57 0.5 0.07

0.013 1.14 0.62 0.54 0.08

0.014 1.2 0.67 0.59 0.08

0.015 1.3 0.70 0.61 0.09

Conclusions

• The deflection of the C shaped Micro cantilever was Calculated using Stoney’s equation mathematically and the same cantilever is (analyzed) simulated using Ansys software.

• Since von mises stress is less than stress intensity the model is in safe zone

• The results shows that the analysis with mathematical and simulated are with in a minimum error of .1 (10%) at an approval.

Q. ?

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