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Machine Design Possible Interview Questions

Machine Design Possible Interview Questions. By: Mr. B. Ramesh , B.E. (Mech), M.E. (CAD), (Ph.D.), Associate Professor of Mechanical Engineering, St. Joseph’s College of Engineering, Jeppiaar Trust, Chennai-119 Ph.D. Research Scholar, College of Engineering Guindy Campus,

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Machine Design Possible Interview Questions

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  1. Machine DesignPossible Interview Questions By: Mr. B. Ramesh, B.E. (Mech), M.E. (CAD), (Ph.D.), Associate Professor of Mechanical Engineering, St. Joseph’s College of Engineering, Jeppiaar Trust, Chennai-119 Ph.D. Research Scholar, College of Engineering Guindy Campus, Anna University, Chennai-25

  2. Questions • What are ISO-9000 standards? ISO-9000 standards are made up of five parts namely ISO-9000, ISO-9001, ISO-9002, ISO-9003 and ISO-9004. ISO-9000 and ISO-9004 are advisory documents. For instance, ISO-9000 contains guidelines for using the standards. The standards are contained in ISO-9001, 9002 and 9003. 2. Which ISO standard would be applicable if the product or the service involved design and development? It would involve ISO-9001 which is the model for quality assurance in design, development, production, installation and servicing. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  3. Questions… 3. Can you tell us about ISO-9002 and 9003 also? ISO-9002 is for quality assurance in production, installation and servicing and ISO-9003 is for quality assurance in final inspection and test. 4. What are the common profiles used for splines in machine elements? The profiles used for splines in machine elements are straight sided splines, triangular splines and involute splines. 5. What type of threads are used for pressure tight joints and for power transmission? Pipe threads are used for pressure tight joints and square threads for power transmission. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  4. Questions… 6. How computer helps in designing? Computer is able to store lot of information and same can be retrieved fast. It performs calculations very fast. The design can be visualized on screen and any alterations made and its effects clearly seen. Thus optimum designs can be achieved much faster and these are thoroughly tested from all angles. 7. Can you tell something about Hazop study? In Hazop (Hazards and operatibility) study each and every conceivable process deviation from normal operating condition of a system having identical design intention, is thoroughly analysed for causes and consequence and required action plan to mitigate hazard/operability problems are suggested on the basis of available protective system. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  5. Questions… 8. Why slenderness ratio is considered in design of members? When length of the member is increased, the member may fail due to buckling even though the member is symmetrical in all respects and the load is concentric. 9. What do you mean by allowance in limits and fits? Allowance in limits and fits refers to maximum clearance between shaft and hole. 10. A wire rope is designated as 6 x 19 standard hoisting. What do the numbers 6 x 19 represent? Number of strands x number of wires in each strand. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  6. Questions… 11. Why a sleeve is fitted on a ball bearing? To prevent relative axial movement between the shaft and the bearing. 12. What is the constant factor in case of R-10 series of preferred numbers? 1.25 13. On what basis a transmission shaft subjected to bending loads must be designed? Maximum shear stress theory. 14. In designing a clutch plate, what assumption is made? Uniform wear condition is assumed because it leads to safer design. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  7. Questions… 15. The critical speed of rotating shaft depends upon what? Mass and stiffness. 16. What is the empirical formula used to give the number of bolts in flange coupling? n = 0.2d + 3 17. How the size of the gear is usually specified? By pitch circle diameter. 18. While taking a turn, what action differential makes? An increase in the speed of the outer wheel. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  8. Questions… 19. Rankine’s and Guest’s theory of failure are applicable for what materials? Rankine’s theory of failure is applicable for brittle materials. Guest’s theory of failure is applicable for ductile materials. 20. What is the most suitable bearing for carrying very heavy loads with slow speed? Roller bearing 21. What is the main purpose of a gear box in a vehicle? To vary the torque at the road vehicles. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  9. Questions… 22. What is endurance limit? Endurance limit or fatigue limit is the maximum stress that a member can withstand for an infinite number of load applications without failure when subjected to completely reversed loading. 23. What is the included angle in unified of American National threads? 600 24. What is the included angle in ACME threads? 290 25. The designation M 33 x 2 of a bolt means Metric threads of 33 mm outside diameter and 2 mm pitch. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  10. Questions… 26. If threads on a bolt are left hand, threads on nut will be Left hand with same pitch. 27. For tight leakage joints, which type of thread is best suited? NPT ( National Pipe Threads) 28. A bench vice has which type of thread? ACME 29. What do you mean by spring index? Ratio of coil diameter to wire diameter (D/d). Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  11. Questions… 30. What do you mean by spring stiffness? Load required to produce unit deflection. 31. For riveted joints, which type of joint is preferred? Butt joint. 32. What do you mean by factor of safety? Ratio of yield stress and working stress. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  12. Questions… 33. Say the use of some couplings. Oldham’s coupling is used to connect two shafts which have lateral misalignment. Universal coupling is used to join two shafts whose axes intersect at a small angle. Bushed pin flexible coupling is used to join two shafts which are not in exact alignment. Sleeve or muff coupling is the simplest type of rigid coupling. 34. What is slenderness ratio? Length of strut/ Least radius of gyration. 35. Spring driven watches and clocks utilize what gears? Cycloid gears. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  13. Questions… 36. What is the standard angle between the sides of V-belt? 400. 37. In design of gears, Lewis equation is used to find what stress? Compressive stress in bending. 38. Zero axial thrust is experienced in what gears? Herringbone gears. 39. What type of cam follower is generally used in automobiles? Spherical type cam follower. 40. Say some types of cam. S.H.M. cam is used in order to minimize jerks. Harmonic cam is used for low and moderate speed engine. Cycloidal cam is used for high speed engine. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  14. Questions… 41. How do you define a spring? A spring is an elastic member which stores energy and provides a force over a distance by elastic deflection. 42. How do you define a shaft? A shaft is a rotating member, usually of circular cross-section (either solid or hollow), transmitting power. 43. What is a flywheel? A flywheel is a heavy rotating body which acts as reservoir for absorbing and redistributing kinetic energy. The function of a flywheel is to keep the speed of machine between given limits while the machine is doing work or receiving energy at a variable rate. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  15. Questions… 44. What is a design? Creating a plan or drawings for a product using intellectual ability and scientific knowledge is called design. A product so designed should permit economical manufacture, and it should meet the specification requirements. 45. What are the different types of design? Adaptive design – Adaptation of the existing design Development design – Improvement of the existing design New design – Design of an entirely new product 46. What is engineering design? Iterative decision making process to conceive and implement optimum systems to solve problems and needs of society. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  16. Questions… 47. What is machine design? A process of achieving a plan for the construction of a machine. 48. What is rational design? A purely mathematical design based upon principles of mechanics of materials and machines. 49. What is empirical design? A design based upon standard practice and past experience. 50. What is industrial design? A design evolved considering aesthetics, ergonomics and production aspects of design. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  17. Questions… 51. What is optimum design? A design which is best and economical for the given objective function under the specified constraints. 52. What is morphology of design? The methodology of design by which ideas about needs are projected creatively into ideas about things, and which in turn are translated into engineering prescription for transforming suitable resources into useful, physical objects. 53. What is preliminary design? To establish an overall concept for the project which will serve as a guide for the detailed design. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  18. Questions… 54. What is anatomy of design? Describing the design process involving a detailed examination of the designer’s action as he goes about identifying and solving the problem. 55. What is modeling? Representation of the real world on desk in symbolic form or in the laboratory. 56. What are preferred numbers? A general basis for standardizing and grading a series of similar dimensions, characteristics, etc. 57. What is resilience? Strain energy stored per unit volume. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  19. Questions… 58. What is proof resilience? The maximum strain energy which can be stored in a material per unit volume. 59. What is creep? The slow and progressive deformation of a material with time under a constant stress. 60. What is knuckle joint? A joint used to connect two rods subjected to tensile loads only. 61. What is cam? A plate or cylinder which communicates motion to a follower by means of its edge or a groove cut in its surface. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  20. Questions… 62. What is coupling? Coupling makes a semi permanent connection between two shafts. 63. What are fluid couplings? Couplings having two basic parts, an impeller and runner, there being no mechanical connection between the two shafts. 64. What are clutches? Couplings which permit the disengagement of the coupled shafts during rotation. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  21. Questions… 65. How CAD software’s are classified? Drafting packages, Modeling packages and Analysis packages. 66. What are the advantages of CAD software’s? High accuracy in drafting. Creating drawing with ease using commands or icons. Editing facilities are allowed easily and quickly. Printouts improve the communication quality. Improves the productivity of a designer. 67. What do you meant by GUI? Graphical User Interface Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  22. Questions… 68. State the different types of Co-ordinate systems. • Polar Co-ordinate system • To Point:@( distance) < (direction) • : @40<45 • Relative Co-ordinate system • To Point : @ X, Y : @40, 30 • Absolute Co-ordinate system • To Point : X, Y : 40, 30 Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  23. Questions… 69. What is the expansion of CATIA? Computer Aided Three Dimensional Interactive Application. 70. What is parametric modeling? Parametric modeling uses parameters to define the dimension of a model . The parameter may be modified later, and the model will update automatically to reflect the modification. Typically, there is a relationship between parts, assemblies and drawings. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  24. Questions… 71. Define element and node. A small unit having definite shape of geometry is called element and these are interconnected by nodes. 72. What are the different types of elements used in FEA? 1-D (Line) Element, 2-D (Plane) Element and 3-D (Solid) Element. 73. What are the different types of stresses and strains in an object? Tensile stress, Compressive stress, Bending stress, Shear stress and Crushing stress. Tensile strain, Compressive strain, Shear strain, Volumetric strain. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  25. Questions… 74. List some softwares that uses FEA as tool. ANSYS (General purpose, PC and workstations) I-DEAS (Complete CAD/CAM/CAE package) NASTRAN (General purpose FEA on mainframes) ABAQUS (Nonlinear and dynamic analysis) COSMOS (General purpose FEA) HyperMesh (Pre/Post Processor) Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  26. Questions… 75. Define aspect ratio. It is defined as the ratio of the largest dimension of the element to the smallest dimension. 76. Specify any two applications of FEA in fluid mechanics. We can find velocity and rate of flow at different sections. 77. What do you understand by discretization of domain? The art of subdividing a structure into a convenient number of smaller components is known as discretization. 78. What role do the computer play in use of the finite element method? Reduces solving time. Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  27. Thank You Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

  28. Four C’s of Design • Creativity • Complexity • Choice • Compromise Design Variables • Geometric Dimensions • Material Type • Tolerances • Engineering Notes

  29. Recognition of Need Definition of Problem The Design Process Synthesis Analysis and Optimization Evaluation Presentation

  30. The Design Process Recognition of Need Computer – Aided Design Definition of Problem The Application of Computers for the Design Process Geometric Modeling Synthesis Engineering Analysis Analysis and Optimization Design Review And Evaluation Evaluation Automated Drafting Presentation

  31. Phase 1: Conceptual design DefineProblem GatherInformation ConceptGeneration EvaluateConcepts ProductArchitecture Config.Design DetailDesign Planning Phase 3 Phases 4 Phase 2: Embodiment design Detailed Description of Design Process

  32. The Concept of Concurrent Engineering Inspection Marketing Manufacturing Design Coordinator Sales Serviceability Packaging Assembly Function

  33. Design of Standards: Standard : • A standard is a generally agreed-upon set of procedures, criteria, dimensions, materials or parts. • Engineering standards may describe the dimensions and sizes of small parts like screws and bearings. • It tells the engineer how to do it. Societies for Standards : • ASME : American Society for Mechanical Engineers • ASTM : American Society for Testing and Materials • AISC :American Institute of Steel Construction • ANSI : American National Standards Institute • ISO : International Organization for Standardization

  34. Few widely used Modeling packages are: • Pro/E • CATIA V5 • UNIGRAPHICS • SOLID WORKS • AUTODESK INVENTOR • IDEAS

  35. General Analysis Procedure Overview Preliminary Decisions Every analysis involves four main steps: • Preliminary Decisions • Which analysis type? • What to model? • Preprocessing • Define Material • Element type • Create or import the model geometry • Mesh the geometry • Solution • Apply loads • Solve • Postprocessing • Review results • Check the validity of the solution Preprocessing Solution Postprocessing

  36. Thank You Mr. B. Ramesh, Associate Professor of Mechanical Engineering, St. Joseph's College of Engineering, Chennai-119

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