PE Mechanical Machine Design and Materials Exam Prep

Machine design asks one question over and over: will this part survive its loads? Answering it takes stress analysis, a failure theory, a fatigue check, and a sensible choice of shaft, bearing, fastener, and material. The algebra is manageable. The judgment is harder: which stress concentration applies, which safety factor is reasonable, which material suits the process. STEM Tutor 360 offers one-on-one prep for the NCEES Machine Design and Materials exam, and it is run by a Georgia Tech mechanical engineer. We start with a diagnostic and rebuild your weakest topics first.

Some candidates last did fatigue, gears, and bearings in a college design course. Others live in one area, such as bolted joints, and meet the rest only on exam day. Sessions slow down on the procedures that trip people up: combined loading and failure theories, fatigue with corrected endurance limits, and standard gear and bearing checks. You practice with the handbook on screen, so you learn where the equations live as you go.

How we build your plan

• A timed diagnostic mixes stress, fatigue, machine element, and materials questions.
• Stress states and failure theories come first, because fatigue, shafts, and fasteners all build on them.
• Machine elements follow in order: shafts and bearings, gears and springs, then fasteners and welds, each with a short procedure card.
• Materials and manufacturing become comparison tables you can rehearse: properties, heat treatment effects, and process tradeoffs.
• Mechanisms, dynamics, and vibration basics come once the design topics are steady.
• Every problem is worked with the handbook open on screen, and every miss is added to an error log.

A sample problem, worked

A steel part carries an alternating stress of 80 MPa and a mean stress of 100 MPa. Ultimate strength is 600 MPa, yield strength is 450 MPa, and the corrected endurance limit is 200 MPa. Find the factor of safety.

Fatigue, with the modified Goodman line: $$\dfrac{1}{n} = \dfrac{80}{200} + \dfrac{100}{600} = 0.400 + 0.167 = 0.567$$ so $n = 1.76$. Yield on the first cycle: $$n = \dfrac{450}{80 + 100} = 2.50$$

The smaller factor governs, so this part is limited by fatigue at $n = 1.76$. Checking both failure modes every time is the habit to build.

About the exam

Machine Design and Materials is one of three separate NCEES PE Mechanical exams. The other two are HVAC and Refrigeration, and Thermal and Fluid Systems. All are computer-based and offered year-round at Pearson VUE test centers.

The exam has 80 questions and about 8 hours of exam time, inside a 9-hour appointment that includes a tutorial and a scheduled break. The NCEES PE Mechanical Reference Handbook is provided on screen, so we practice with it that way. For the exact topic list and question weights, read the current NCEES exam specification. STEM Tutor 360 is independent and not affiliated with NCEES.