StructuresKamal Mahmud

Personal Responsibilities

• Casing stress analyses• Static • Thermal • Burst

• Casing design• Based on the stress results

FEA and ANSYS

• Finite element analysis (FEA) using ANSYS 12.1

• CAD modelling using Pro/E v3, v5• Linear and non-linear, steady-state and

transient analyses• Types of analyses:

• Static Structural• Thermal• Vibration• Explicit Dynamics

Casing Design

• Design modifications

2009/10 Model 2010/11 Model

CAD Model Difficulties

• Complex features• Swept blend

• File transfer difficulties• Defeaturing

Include final pic & caption

Defeatured casing Final casing

Challenges Faced

• File compatibility• Defeaturing problem• Redesigning• Advanced options• Partitioning (slice)• CAD repair• Meshing

• Patch independent• Tetrahedral and sweep

Flow Path

Stress Analysis

• CF8C Plus as material• Yield stress = 300 MPa

• Static and thermal stress analysis• Simulate extreme case scenario• Operational pressures and temperatures

• Von-Mises stress and deformation• Analytical calculation and validation

Static Stress – Extreme Case

• 25 MPa uniform pressure – extreme case• Used for most analyses• Validation analytically

Thermal Stress – Extreme Case

• 25 MPa pressure and 750°C temperature

Thermal Stress - Operational

• Varying pressure and temperature at different sections

• Redesigning may be

required

Modal Analysis

• Pre-stress modal analysis• Static and thermal stress

• Operating speed = 9720 rpm• Structurally safe

Mode 1 = 6500 rpm Mode 2 = 7200 rpm Mode 3 = 10300 rpm

Burst Analysis and Research

• Explicit Dynamics workbench• Turbine rotor at 9720 rpm and 12700 rpm• Tri-hub rotor burst• Casing thickness determined analytically

• Energy based calculation

• MIT report “Finite-Element Analysis of Simulated Rotor-Fragment Impacts Against Rings & Beams Compared with Experiments” [1]

[1] J.J.A Rodal et al., Aeronautics and Astronautics department, MIT, 1965

Burst Analysis Video

This video is uploaded separately in my linkedin profile

Future Work

• Casing stress analysis• Casing redesign

• Lessons learned from 2010/11• CAD model with minimum imperfections• Detailed design• Assembly procedure

• Burst analysis• Advanced techniques• Simulation for different failure modes

Questions?

Thermal Complete Stress

Modal Burst