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25-Nav-B1 Applied Thermodynamics and Heat Transfer (25-Mec-A1): May 2016

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Short-Answer Set — Green Design, Shafts, Bearings & Yield Criteria
  2. Question 2 Twin Acme Power Screws Raising a Sluice Gate
  3. Question 3 Simply Supported Round Beam — Reactions, SFD/BMD, Bending Stress
  4. Question 4 Single-Surface Disk Clutch Design (Uniform Wear)
  5. Question 5 Rotating Shaft — Fatigue Diameter and Deflections
  6. Question 6 Notched Bar in Axial Fatigue

Start with Question 1 →

National Exams — May 2016 · 98-Mar-B1 Advanced Machine Design. Open-book, 3 hours, 100 marks. Part I (Problems 1–2) is compulsory; candidates answer any three of the four Part II problems (3–6). For study value, complete worked solutions to all six problems are provided below.

Reference texts. R.G. Budynas & J.K. Nisbett, Shigley’s Mechanical Engineering Design, 10th ed. (power screws §8-2, clutches §16-5, shaft fatigue §7-4/§6, notch factors §6-10); R.C. Juvinall & K.M. Marshek, Fundamentals of Machine Component Design (screws, clutches); R.C. Hibbeler, Mechanics of Materials (beam reactions, bending stress, deflection).

Check — paper content and assumptions. This paper, although listed under Applied Thermodynamics and Heat Transfer, is headed “98-Mar-B1” with printed title “Advanced Machine Design”; it is a general mechanical machine-design paper — green-design/yield-theory short answers, Acme power-screw torque, beam reactions/SFD/BMD/bending stress, disk-clutch sizing, shaft fatigue with deflections, and notched-bar fatigue — with zero thermodynamics or heat-transfer content, and it is solved as the exam actually printed. Engineering assumptions stated per the exam rubric: (1) “ton” is read as the US short ton (2000 lb), consistent with the inch/ft·min/hp unit set of Problem 2. (2) In Problem 3 the concentrated couple Mz is taken counter-clockwise (out of the page, per the dot symbol in the figure); a clockwise reading would give RA = 0, RB = 9.5 kN. (3) In Problem 5 the fluctuating torque is assumed transmitted over the 18 in from the drive end to the load; no stress concentration is used as the problem directs.