Presentation is loading. Please wait.

Presentation is loading. Please wait.

Initial Work on Acoustic Simulation using Ansys APDL

Similar presentations

Presentation on theme: "Initial Work on Acoustic Simulation using Ansys APDL"— Presentation transcript:

1 Initial Work on Acoustic Simulation using Ansys APDL
Presented by Lee Chean Shen General Engineering Research Institute Electronic and Ultrasonic Engineering Group Supervisors Prof. Dave Harvey Dr. Guangming Zhang 22 January 2010

2 Destructive & Non Destructive tools.
Introduction – Acoustic Microscopy What is Acoustic? Longitudinal wave which consists of compression and dilation Infrasound Audible Ultrasound Human Hearing 20Hz 20kHz 100kHz Animal Navigation & Communication Seismology Medical Diagnostics. Destructive & Non Destructive tools. Destructive Ultrasound (>10 W/cm2) Sonochemistry Welding Cleaning Cell Disruption Kidney Stone Removal Non-Destructive Ultrasound (0.1 – 0.5 W/cm2) Flaw detection Medical Diagnosis Sonar Chemical Analysis

3 Introduction – Acoustic Microscopy
What is Acoustic Microscopy Imaging (AMI)? Non-Destructive technique Sensitive to voids, delaminations and cracks Detects flaws down to sub-micron Image nontransparent solids or biological materials Study microstructures of specimen X-Ray AMI Unreflowed Solder Bump, AMI presents better contrast of defect

4 Introduction – Acoustic Microscopy
Resolution characteristics of AMI technique. Increasing frequency largely lowers depth penetration Attenuation usually increase with frequency Lower frequency reduces resolution More information captured 230MHz 50MHz

5 Introduction – Acoustic Microscopy
AMI Operational Characteristics - Transducer Transducer is cut/tuned to specific frequency, typically three types; Piezoelectric High frequency, low power (MHz region) Voltage applied to crystal, medium required Transducer is cut to frequency Magnetostriction (EMAT) Metal core responds to magnetic field Material dependant, no coupling required Photoacoustic Pulsed laser applied to specimen Thermal wave phenomena Very high frequency Measures material properties

6 Introduction – Acoustic Microscopy
AMI Operational Characteristics - Medium Tranducer lensed to modify beam focus Ansys Model Construction (results in Review section)

7 Introduction – Acoustic Microscopy
AMI Operational Characteristics - Medium EMAT only applicable to specific materials Photoacoustic may require protective layer Piezoelectric - Couplant required Usually deionized water Reflection occurs at the interface between two mediums Air has low acoustic Impedance (Z) Z = ρV = density * sound velocity of medium Water to Steel ratio ~ 20:1 Air to Steel ratio ~ 100,000: (near 100% energy reflected) Pulse Echo Change in Impedance (Interface)

8 Introduction – Acoustic Microscopy
AMI Operational Characteristics - Configuration Two typical methods Pulse Echo – Image derived from reflections (Popular) Through Transmission – Image derived from received signal Through Transmission Pulse Echo Gate

9 Issues Current issues facing AMI
Electronic packages are shrinking and/or stacking Technique is approaching resolution limits Image processing techniques not broadly reliable Transducers have relatively narrow operational frequencies Optimal frequency difficult to determine

10 Objectives Nonlinear acoustic Imaging
2nd order harmonic provides higher resolution Common in medical acoustics Require single frequency transducer Penetration depth proportional to fundamental wave Not all material generate harmonic waves Generated waves needs to reach receiver Explore implementation on stacked (3D) die

11 Objectives Clarify defect detection mechanism
Limited published literature regarding subject Primary focus on new generation 3D IC packages Understand acoustic performance within 3D IC packages Balance optimum resolution vs. penetration Analyze defect detection mechanism of engineered faults

12 Methodology - Ansys What is Ansys?
Finite Element Multiphysics Simulation Software Accurate simulation of complex coupled-physics behaviour Broadly defined into two interface Structural Mechanics Explicit Dynamics Electromagnetics Fluid Dynamics Acoustics ETC Ansys Mechanical APDL Ansys Workbench

13 Methodology - Ansys What is Finite Element Method?
Complete system is distributed into a large number of discreet elements Complex system of nodes which form mesh grids Mesh grid contain material and structural properties Area anticipating stress/load tend to have higher density of node Mesh resolution increases computational time

14 Tetrahedral (triangular)
Methodology - Ansys Comparison of Mesh Resolution Models usually tested with multiple mesh resolution/configuration Ensure circular areas are adequately smooth/circular Mesh resolution and type fits geometry size Generally “look right”, results largely determined by mesh quality Tetrahedral (triangular) Hexahedral (square) Fine Mesh Coarse Mesh Coarse Mesh Fine Mesh

15 Methodology - Ansys What is Ansys Mechanical APDL ? Also known as;
Ansys Classic “Old” Ansys Reliant mostly on command lines and scripts Primitive GUI

16 Methodology - Ansys What is Ansys Workbench?
Ansys with user friendly GUI “Idiot-proof” Ansys Powerful module based project assembly/management

17 Review Transducer Simulation – Pressure Magnitude
1500m/s (water medium) Ansys APDL Mirror Result Mirror Result Main Lobes Side Lobes

18 Review Transducer Simulation – Acoustic Lens
1500m/s (water medium) Triangular 15 elements per wave Expected shift of focus point Node reaction to applied load PCIRC,0,1,0,90 RECTNG,0,0.025,0,0.1 CYL4,0,0.25,0.2 (double radius) pcirc,0,1,0,90 RECTNG,0,0.025,0,0.1 CYL4,0,0.15,0.1

19 Further Work Scale up transducer simulations to MHz region
Validate simulation with measured results Implement Non-Linear simulation General simulation cleanup Introduce materials into focused region Study acoustic defect detection mechanism

20 Thank You

21 Source & Citations Eindhoven University of Technology
The Principles of Medical Ultrasound HyperPhysics Utrasound Guide – Georgia State University CALCE – University of Maryland Acoustic Microscopy Guide – University of Hawaii Resolution improvement of acoustic microimaging by continuous wavelet transform for semiconductor inspection – LJMU GERI Guang-Ming Zhang, David M. Harvey, Derek R. Braden. The NDE Analysis of Tension Behaviour in Nicalon/SiC Ceramic Matrix Composites Jeongguk Kim, Peter K. Liaw, Hsin Wang Fundamentals of Ultrasonic Imaging and Flaw Detection – National Instruments Phased Array Tutorial - Olympus About HIFU – Maple Leaf HIFU Finite-element method – McGill University Introduction to Finite Element Analysis – Virginia Tech Modeling and Meshing Guide, Chapter 7 – Ansys

Download ppt "Initial Work on Acoustic Simulation using Ansys APDL"

Similar presentations

Ads by Google