Overview of FE Mechanical Engineering
The Mechanical Engineering discipline on the FE exam tests your understanding of core mechanical engineering principles including thermodynamics, fluid mechanics, heat transfer, machine design, and dynamics. Mechanical engineering is one of the broadest FE disciplines, requiring knowledge that spans from microscale material properties to large-scale system design.
Key Topics
Thermodynamics
Thermodynamics is heavily tested on the FE Mechanical exam. You must understand the first and second laws of thermodynamics, property relationships for ideal gases and steam (using steam tables), power cycles (Rankine, Brayton, Otto, Diesel), refrigeration cycles (vapor compression, heat pumps), and psychrometrics. Know how to calculate work, heat transfer, entropy changes, and thermal efficiency for each cycle. Understand T-s and P-v diagrams and how to trace processes on them.
Fluid Mechanics
Fluid mechanics topics include fluid properties (viscosity, density, surface tension), hydrostatics (pressure distribution, forces on submerged surfaces, buoyancy), the Bernoulli equation, the continuity equation, the momentum equation for control volumes, dimensional analysis (Buckingham Pi theorem), pipe flow (laminar and turbulent, Reynolds number, Moody chart, major and minor losses), and external flow (drag and lift coefficients). Understand pump performance curves and system curves.
Heat Transfer
Know the three modes of heat transfer: conduction (Fourier's law, thermal resistance networks, fins), convection (Newton's law of cooling, forced and natural convection correlations, Nusselt number), and radiation (Stefan-Boltzmann law, view factors, blackbody and graybody exchange). Understand heat exchangers (LMTD method, effectiveness-NTU method, parallel flow, counterflow, crossflow configurations) and how to size them for a given duty.
Machine Design and Mechanics of Materials
This area covers stress analysis (axial, bending, torsion, combined loading), Mohr's circle, fatigue analysis (S-N curves, endurance limit, Goodman diagram), bolted and welded connections, bearing selection, gear and belt drive design, and spring design. Understand failure theories (maximum shear stress, distortion energy) and how to apply factors of safety. Know how to calculate deflections, critical speeds, and buckling loads (Euler's formula).
Dynamics and Vibrations
Dynamics topics include kinematics and kinetics of particles and rigid bodies, work-energy methods, impulse-momentum methods, and free and forced vibrations of single-degree-of-freedom systems. Understand natural frequency, damping ratio, resonance, and how to model simple vibrating systems. Know Newton's second law in both translational and rotational forms.
Study Strategy
Thermodynamics and fluid mechanics together account for a large portion of the mechanical exam, so invest significant time in those areas. Practice working with steam tables and the Moody chart from the FE Reference Handbook. For machine design, focus on combined stress problems and fatigue analysis. Time yourself on practice problems to build speed.