Stress and Deformation Analysis of Jet Engine Fan Blades under Operational Loads Using FEM

Abstract

The performance and reliability of jet engine fan blades are critical for aerospace applications, where materials are subjected to high rotational speeds, thermal loads, and mechanical stresses. This study investigates the mechanical behaviour of fan blades constructed from Nickel Alloy, Titanium Alloy, and Ceramic Matrix Composites (CMC) under operational loads using the Finite Element Method (FEM). The analysis incorporates total deformation, von Mises stress, and von Mises strain as key performance indicators. Nickel Alloy demonstrated moderate deformation (0.21428 mm) with stress levels (314.71 MPa) within safe limits, confirming its historical usage in turbine components. Titanium Alloy offered weight reduction but exhibited higher deformation (0.29623 mm) and stress (391.55 MPa), suggesting a trade-off between structural flexibility and mechanical robustness. CMC blades showed superior stiffness with minimal deformation (0.17892 mm) and low stress (199.34 MPa), highlighting their potential for high-efficiency designs; however, their brittle nature poses reliability challenges under impact loads. A comparative analysis emphasizes design trade-offs, demonstrating that while CMC offers the highest efficiency, Nickel and Titanium alloys remain practical due to toughness and fatigue resistance. The study provides insights for material selection, blade geometry optimization, and performance enhancement in modern aero engine applications, offering a foundation for future research on hybrid or coated composite blades to address brittle fracture risks.

Introduction

1. Overview

• Fan blades in jet engines face extreme mechanical and thermal conditions (high-speed rotation, centrifugal forces, thermal gradients, vibrations).

• The performance, safety, and efficiency of the engine are directly influenced by the fan blade material and structural design.

• Key materials evaluated:

  • Nickel Alloy: High strength, excellent creep resistance, durable at high temps.

  • Titanium Alloy: Lightweight, high strength-to-weight ratio, efficient but more deformable.

  • Ceramic Matrix Composites (CMC): High stiffness, low density, excellent thermal stability, but brittle.

???? 2. Study Objectives

The study aimed to:

1. Evaluate mechanical performance of the three materials under identical operational loading.

2. Compare stress, strain, and deformation behavior.

3. Identify the optimal material considering safety, durability, and performance.

???? 3. Material Properties Summary

???? 4. Methodology

• 3D blade model developed in CATIA, capturing detailed geometry (root, midspan, tip).

• Imported into ANSYS Workbench for FEM simulation.

• Fine meshing applied to ensure accuracy, especially near root-fillet areas (stress hotspots).

• Static structural analysis conducted with:

  • Centrifugal loading

  • Fixed rotational constraints

  • Identical boundary conditions for each material

???? 5. Results Summary

???? Deformation, Stress & Strain (Table)

• CMC had the lowest deformation and stress, confirming superior stiffness, but brittleness is a concern.

• Titanium showed the highest deformation and stress, though it's light and strong—ideal for weight-sensitive designs.

• Nickel Alloy offered a balance of strength and toughness, performing well under high temperature and stress.

???? 6. Literature Insights

• Nickel Alloy: Great fatigue and creep resistance (Smith et al., Singh & Agarwal).

• Titanium Alloy: Excellent weight saving but sensitive to stress concentration (Kumar & Patel, Rao et al.).

• CMC: Excellent thermal and mechanical stability; brittle and impact-sensitive (Chen et al., Ahmed et al.).

• FEM is widely validated for simulating complex rotational and thermal loads in aerospace components.

? 7. Key Takeaways

• CMC is the most dimensionally stable, but brittle—best for high-temp, low-impact environments.

• Titanium Alloy offers lightweight advantage but needs careful design to manage high stresses.

• Nickel Alloy is reliable and tough, making it suitable for high-cycle fatigue and high-temperature environments.

???? 8. Design Considerations

• Root fillet geometry is critical—stress concentrations often originate here.

• Material selection should account for:

  • Cyclic fatigue

  • Thermal expansion

  • Impact loads

  • Weight-efficiency trade-offs

Conclusion

This study evaluated Nickel Alloy, Titanium Alloy, and CMC fan blades using FEM. Nickel Alloy demonstrated a balance of strength and ductility, with moderate deformation and stress levels suitable for conventional designs. Titanium Alloy offered reduced weight, improving engine efficiency, but higher deformation and stress require careful design. CMC showed minimal deformation and stress, ensuring aerodynamic stability and efficiency; however, its brittleness necessitates impact mitigation strategies.Comparative analysis indicates that while CMC is ideal for minimizing stress and deformation, Nickel and Titanium alloys remain practical for reliability and toughness. Stress concentrations at root fillets highlight the importance of geometric optimization. FEM analysis proves invaluable in predicting mechanical performance, guiding material selection, and informing design improvements. Future blade designs may incorporate hybrid materials or protective coatings to combine stiffness, weight savings, and ductility. The study provides a foundation for optimizing next-generation fan blades for aerospace applications, balancing performance, efficiency, and safety.

References

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Copyright

Copyright © 2025 Neelesh ., Rajesh Khodre. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.