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FINITE ELEMENT SIMULATION OF ND:YAG LASER SHOCKPEENED NICKEL CHROME, COBALT CHROME BASE METAL ALLOY FOR DENTAL APPLICATION ILAVARASAN S 2010118017 KARTHIKEYAN S 2010118024 KUMAR K 2010118026 SARATH RAJA G 2010118040 Project Guide Dr. K Shanmuga Sundaram Associate Professor Department of Mechanical Engineering College of Engineering, Guindy Anna University, Chennai-25

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Page 1: FEA Simulation

FINITE ELEMENT SIMULATION OF ND:YAG LASER SHOCKPEENED NICKEL

CHROME, COBALT CHROME BASE METAL ALLOY FOR DENTAL APPLICATION

ILAVARASAN S 2010118017

KARTHIKEYAN S 2010118024

KUMAR K 2010118026

SARATH RAJA G 2010118040Project Guide Dr. K Shanmuga Sundaram

Associate ProfessorDepartment of Mechanical Engineering

College of Engineering, GuindyAnna University, Chennai-25

Page 2: FEA Simulation

IntroductionThe main objective of this project is to give a solution to the

material selection for the dental implants or any other dental treatments.

Dental Implants are become necessary now a days. Because,

• 69% of adults at an age of 35 to 44, lost at least one of their permanent teeth by accident, gum disease or failed root canal.• 26% of adults at an age of 74, have lost all their permanent teeth.

Page 3: FEA Simulation

Objective Selecting the suitable material,

laser for the dental application and comparing the changes in the mechanical properties after doing shock peening operation

Hardness Wear resistance Yield strength Ultimate strength Modulus of Elasticity

The experimental results and the theoretical results (simulation) are compared and studied

Page 4: FEA Simulation

Material SelectionSelection of Materials are based on the following things,

• Bio compatibility• Color• Life • Durability• Easy for shaping• Aesthetics• Physical properties

• Low thermal conductivity and expansion• Resistance to wear and abrasion• Resistance to chemical erosion

• Flexibility to adopt to a shape• Strength to withstand the Mastication force

Page 5: FEA Simulation

Material Selection Disadvantages • Poor Strength• High cost• Low Wear resistance• Less aesthetics• Takes longer time to make• Difficult to adjust• Dull in tooth color• May irritate the sensitive teeth (conducts cold)• High cost• Galvanic Shock• More brittle• Less life• Chance for future cavities• More time to place

o Gold Alloyo Porcelaino Plastic + Fine

Glasso Titaniumo Cobalt

Chromiumo Nickel Chrome

Page 6: FEA Simulation

Suitable MaterialsCHEMICAL COMPOSITION :: Ni-Cr CHEMICAL COMPOSITION :: Co-Cr

ELEMENT PROPOSITION

NICKEL 65.2 %

CHROME 22.5 %

MOLYBDENUM 9.5 %

OTHERS (Fe, Si, Mn, Nb)

2.8 %

ELEMENT PROPOSITION

COBALT 61 %

CHROMIUM 26 %

MOLYBDENUM 6 %

TUNGSTEN 5 %

OTHERS (Si, Fe, Ce) 2 %

Page 7: FEA Simulation

Laser Shock Peening Innovative surface enhancement process for

increasing resistance of the components. This process creates compressive stress, four to

five times deeper than conventional shot peening process.

This compressive surface stresses inhibit the initiation and propagation of fatigue cracks.

The peening drives a high amplitude shock wave into a material surface using high energy pulsed laser.

Hence the purpose of this study is to compare mechanical properties with microstructure of Nd-YAG laser treated and non-treated on Ni-Cr and Co-Cr

Page 8: FEA Simulation

Nd: YAG Laser Shock peening• 0.4 mm to 1 mm• Low cost and easily available• produce continuous laser at

room temperature• portable systems

Page 9: FEA Simulation

Parameter

ConstantSpot Diameter 1.2 mmPulse Duration 10 msDepth of Penetration 0.48 to 0.73 mmArgon Shielding 450

Peening Speed 160 mm/sNo of Scan per Second 4

Variables Pulse Energy Density 450 , 340 , 430 J/cm2

Pulse Frequency 1.1, 0.5, 2.5 kHz

Tensile Specimen using Pro/E

Page 10: FEA Simulation

Finite Element Analysis Structural – Static Analysis Solid 185 Element Size 0.0001 (Fine

Mesh)

Meshed view of Specimen

Page 11: FEA Simulation

Displacement Vector Sum X Component Displacement

Y Component Displacement Z Component Displacement

Page 12: FEA Simulation

1st Principal Stress Von Mises Stress

XY Shear Stress Z Component Stress

Page 13: FEA Simulation

1st principal Strain Von Mises Strain

Z Component Strain Elastic Strain Intensity

Page 14: FEA Simulation

Improved Mechanical Properties

Vector Plot of Displacement

Vector Plot of Elastic Strain

Page 15: FEA Simulation

ResultThe Strain value of the Co-Cr Alloy got the smallest value than

the Ni-Cr Alloy. So the less strain value material is opted for Dental applications.Obviously Co-Cr alloy is better than Ni-Cr alloy.

Maximum Strain Value of Ni-Cr alloy : 657 Maximum Strain Value of Co-Cr alloy : 553

Page 16: FEA Simulation

ResultSince the Co-Cr alloy is suitable for dental applications, the

Laser Parameter can be identified.

Pulse Energy Density value at max. strain value is 360×104J/m2

Pulse Energy Density value at min. strain value is 420×104 J/m2

So the least strain value is occurred during the Pulse Energy Density value of 420 ×104 J/m2

Page 17: FEA Simulation

ConclusionLaser Shock Peening process is a trendsetter now a days in the

medical field. It’s low cost and accurate operations make it popular. So that it gives an exact solution for all kind of age group who are all came with a dental problem.

Nickel Chromium and Cobalt Chromium are some important materials in dental implants. These materials can be used in dental applications without doing shock peening process. But it cannot withstand for a longer period. LSP improves the fatigue strength and compressive stress of the material.

The aesthetics of Co-Cr is little lower than Ni-Cr. Otherwise Co-Cr is the strongest material and can be shaped into any molar shape.

Page 18: FEA Simulation

REFERENCES[1]O Brian WJ. 2002 Dental Materials and their selection. Chicago IL. Quintessence Publishing Co., Inc.; 2002.p.372-377

[2]Ding K, Ye L. Laser Shock peening performance and process simulation. Cambridge: Woodhead Publishing; 2006

[3]Ballard P. Residual Stresses induced by rapid impact – Application for laser shocking. Ecolo Polytechnique, April 1991

[4]Philips and Anusavic. Science of Dental Materials