Thursday, August 27, 2009

Mechanical Engineering Board Exam Questions Part 4






Source: Machinery's Handbook
Topic: Materials and Processes




1.______is a number indicating how many times a certain volume of a material is heavier than an equal volume of water
a.specific ratio
b.density
c.Specific gravity
d.Avogadro's Number

2._______an instrument for determining the density of liquids, provided with graduations made to an arbitrary scale
a.hygrometer
b.hydrometer
c.weighing scale
d.sphygmomanometer

3. Stainless steels generally contain at least _______ chromium, with or without other elements
a.40%
b.30%
c.20%
d.10%

4.______ is type of stainless steel that is nonmagnetic in the annealed condition, although some may become slightly magnetic after cold working
a.austenitic
b.hematite
c.martensitic
d.ferritic

5. ______ grades of stainless steel are always magnetic and contain chromium but no nickel.
a.austenitic
b.hematite
c.martensitic
d.ferritic




6. _______ grades of stainless steel are magnetic and can be hardened by quenching and tempering.
a.austenitic
b.hematite
c.martensitic
d.ferritic

7.The steel is heated to a temperature above the critical range, after which it is cooled in still air to produce a generally fine pearlite structure. The purpose is to promote
uniformity of structure and properties after a hot-working operation such as forging or extrusion.
a. Stress Relieving
b. Spheroidize Annealing
c. Annealing
d. Normalizing

8. This process reduces internal stresses, caused by machining, cold working, or welding, by heating the steel to a temperature below the critical range and holding it there long enough to equalize the temperature throughout the piece.
a. Stress Relieving
b. Spheroidize Annealing
c. Annealing
d. Normalizing

9. This is a special form of annealing that requires prolonged heating at an appropriate temperature followed by slow cooling in order to produce globular carbides, a structure desirable for machining, cold forming, or cold drawing, or for the effect it will have on subsequent heat treatment.
a. Stress Relieving
b. Spheroidize Annealing
c. Annealing
d. Normalizing

10. The steel is heated to a temperature above or within the critical range, then cooled at a predetermined slow rate (usually in a furnace) to produce a coarse pearlite structure. This treatment is used to soften the steel for improved machinability; to improve or restore ductility for subsequent forming operations; or to eliminate the residual stresses and microstructural effects of cold working.
a. Stress Relieving
b. Spheroidize Annealing
c. Annealing
d. Normalizing
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Tuesday, August 25, 2009

Mechanical Engineering Board Exam Questions Part 3






Source: Machinery's Handbook
Topic: Strength of Materials, Springs and Wire Ropes


Answers in RED.

1. These washer type springs can sustain relatively large loads with small deflections, and the loads and deflections can be increased by stacking the springs.
a. Volute springs
b. Torsion bars
c. Belleville
d. Flat springs

2. These springs are often used on army tanks and heavy field artillery, and seldom find additional uses because of their high cost, long production time, difficulties in manufacture, and unavailability of a wide range of materials and sizes
a. Volute springs
b. Torsion bars
c. Belleville
d. Flat springs

3. These springs are often used to overcome operating space limitations in various products such as electric switches and relays.
a. Volute springs
b. Torsion bars
c. Belleville
d. Flat springs

4.The ______ of a wire rope is the direction of the helical path in which the strands are laid and, similarly, the lay of a strand is the direction of the helical path in which the wires are laid.
a. lay
b. Strand Construction
c. stranding
d. ley

5. In ______, the wires and strands are laid in the same direction.
a. regular lay
b. alternate lay
c. lang lay
d. double lay


6. In a wire rope designation 6 X 7, the first number stand for.
a. nominal diameter of the wire rope (in mm)
b. diameter of each strand (in mm)
c. wires per strand,
d. number of strands

7. 6 X 7 class of wire rope is also known as...
a.Standard Hoisting Rope
b.Extra Flexible Hoisting Rope
c.Standard Coarse Laid Rope
d. Special Flexible Hoisting Rope

8. 6 X 19 class of wire rope is also known as...
a.Standard Hoisting Rope
b.Extra Flexible Hoisting Rope
c.Standard Coarse Laid Rope
d. Special Flexible Hoisting Rope

9. 8 X 19 class of wire rope is also known as...
a.Standard Hoisting Rope
b.Extra Flexible Hoisting Rope
c.Standard Coarse Laid Rope
d. Special Flexible Hoisting Rope

10. _____ type of wire rope core is used for small ropes such as sash cord and aircraft cord.
a. Asbestos cores
b. Fiber
c. Cotton
d. wire-strand core

Thursday, August 20, 2009

Mechanical Engineering Board Exam Questions Part 2






Mechanical Board Exam Questions from Machinery's Handbook.
Topic: Machine Design : Strength of Materials


1.______ is the amount by which a dimension of a body changes when the body is subjected to a load, divided by the original value of the dimension
a. stress
b. unit strain
c. modulus of resilience
d. modulus of elasticity

2.______is the maximum stress to which a test specimen may be subjected and still
return to its original length upon release of the load.
a. elastic limit
b. rupture point
c. yield point
d. elastic limit

3. _______ is the ratio of unit stress to unit strain within the proportional limit of a material in tension or compression.
a. Modulus of Elasticity
b. Modulus of Resilience
c. Strain
d. unit strain

4._______is the ratio of lateral strain to longitudinal strain for a given material
subjected to uniform longitudinal stresses within the proportional limit.
a. Poisson's ratio
b. unit stress
c. strain
d. Young's modulus of elasticity

5._______is the maximum stress that can be applied without permanent deformation of the test specimen.
a.Yield Strength
b. Yield Point
c. Utimate Strength
d. Rupture strength


6. _______ is the ratio of unit stress to unit strain within the proportional limit of a material in shear.
a. Modulus of Elasticity
b. Modulus of Resilience
c. Modulus of Rigidity
d. Young's Modulus

7. When strain cycling is produced by a fluctuating temperature field, the failure process is termed _____.
a. Thermal Fatigue
b. Corrosion Fatigue
c. Surface or Contact Fatigue
d. Creep

8. ______ is the ratio of length l of the column in inches divided by the least radius of gyration r of the cross-section.
a. Poisson's ratio
b. slenderness ratio
c. strain
d. Modulus of elasticity

9.Rankine formula for colunms is also known as...
a. Straight line formula
b. Gordon's Formula
c. secant formula
d. Euler's Formula

10. This is the most widely used of all spring materials for small springs operating at temperatures up to about 250F.
a.Music Wire
b.Oil-Tempered MB Grade
c.Oil-Tempered HB Grade
d.Hard-Drawn MB Grade

11.This general-purpose spring steel is commonly used for many types of coil springs where the cost of music wire is prohibitive and in sizes larger than are available in music wire.
a.Music Wire
b.Oil-Tempered MB Grade
c.Oil-Tempered HB Grade
d.Hard-Drawn MB Grade

12.This grade is used for general-purpose springs where cost is the most important factor.
a.Music Wire
b.Oil-Tempered MB Grade
c.Oil-Tempered HB Grade
d.Hard-Drawn MB Grade

13. This alloy, the first constant-modulus alloy used for
hairsprings in watches, is an austenitic alloy hardened only by cold-drawing and cold-rolling.
a.Elinvar
b.Elgiloy
c.Dynavar
d.Ni-Span C

14.This spring service is for 1,000 to 10,000 deflections.
a.Severe Service
b.Light Service
c.Average Service
d.Extra Light Service

15.______ is the highest stress, or range of stress, in pounds per square inch that can be repeated indefinitely without failure of the spring.
a. Endurance Strength
b. Endurance limit
c. Elastic Limit
d. Proportional Limit

More questions to come from Machinery's Handbook. Always visit this site for regular updates or subscribe on a reader or through email.

Tuesday, August 11, 2009

PROBLEM SOLVING TECHNIQUE—Root Cause Analysis






During college, we solve a lot of problems. Mathematics, physics, machine design and thermodynamics were just a few examples. The good thing about these problems is that usually:




1. All needed information and parameters were given. All you have to do is to solve it using formulas and equations.

2. We are sure that the question has an answer.

Newton's dynamical equations.Image via Wikipedia


3. When you already find the correct answer, the problem is done.

That’s the good thing about solving problems theoretically. But when it comes to the actual work, everything is completely different. Some actual problems in the work are:

PIPING: “the pressure on a particular pipe is usually high”

MANUFACTURING: “the dimension of the parts coming out of the machine is off-spec”

FARMING: “the crops do not yield good fruits.”

EDUCATION: “the students’ score dropped dramatically”

In contrast to college problems, actual work problem are one or all of the following.

1. There’s none or insufficient information or parameters known. The “given” or parameters were all part of the problem itself. You have to conduct research and tests to find out the important parameters to be considered.

2. Sometimes, there are problems that has no answer or nearly impossible to answer.

3. Finding the answer to a specific question will lead to more questions and will reveal the complexity of the problem you once thought to be simple.


Root Cause Analysis



One common error in problem solving is trying to solve the effect rather than the root cause. The root cause is different from just an ordinary “cause” because the latter can also be on itself, an effect of a deeper cause. Digging into the base or the root of the problem is what refered to as root cause analysis. Solving just the effect is a waste of time because the real source of the problem is not fixed. The effect will keep on coming back or will just take another form. Solving just the effect is like curing a symptom rather than the true disease.

An icon from the Crystal icon theme.Image via Wikipedia


Root cause determination is the first step before thinking of solving a particular problem. In some cases, the problem is so complex that it already branched out to many sub issues. This makes root cause determination even more difficult.



Good thing to know that there are many techniques to ease the process of root cause analysis. On the next article, we will discuss two of the known techniques used in solving tough problems. They are:

Cycle diagram of the D6 groupImage via Wikipedia


Fishbone Diagram and 5 Why’s

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Sunday, August 2, 2009

Mechanical Engineering Review Materials: PSME Code (With Answer)






As promised on the previous articles, I prepared some materials for the upcoming Mechanical Engineering Board Exam. I hope this one will help.


Update: Answers in red.

Questions from the Philippine Mechanical Code (PSME Code)

1. As a requirement for permit application, for any installation involving machine, mechanical equipment, general layout plan for each floor drawn should not be less than
a. 1:200 b. 1:500 c. 1:1000 d. 1:100

2. Standard sheet sizes for mechanical plans and drawings shall be based on a width to length ratio of
a. 1: sqrt (2) b. 1:sqrt(3) c. 1:3 d. 1:2

3. For commercial and industrial buildings, work rooms (referring to maintenance shop and machine room) shall be at least _______ height from floor to ceiling.
a. 3 000 mm b. 2 000 mm c. 5 000 mm d. 4 000 mm

4. For guyed steel stacks, the angle between the stack and guy wire is usually
a. 30º b. 45 º c. 60 º d. 75 º

5. It is a heavy wheel which by its inertia assists in securing uniform motion of machinery by resisting sudden changes of speed.
a. cartwheel b. flywheel c. motor d. shaft





6. The extension of piston rod passing through a stuffing box in the outside area of an engine cylinder, compressor cylinder or pump cylinder.
a. tail rod b. pin c. hub d. sprocket

7. Type A sprocket has
a. one hub c. no hub
b. two side hubs d. bolted hubs

8. The reciprocating machine part within a cylinder is called
a. ram c. slide mandrel
b. plunger d. all of the above

9. Fixed-mounted or movable hood guards covering the length of run of power chains.
a. coupling guards c. belt guards
b. chain guards d. hood guards

10. A boom type mobile crane mounted on endless tracks or thread belts.
a. gantry crane c. locomotive crane
b. jib crane d. crawler crane

11. A mechanical contrivance for raising or lowering a load.
a. crane b. hoist c. rope d. chain

12. A horizontal arm for supporting a trolley or fall blocks which does not change its inclination with the horizontal.
a. clevis b. boom c. hood d. jib

13. One hand signal for crane movement arm extended, palm down, hold position rigidly.
a. stop b. lower c. hoist d. swing boom

14. Two hand signal for crane movement hold both arms horizontally at sides fully extend and move upward & return.
a. stop b. lower c. hoist d. swing boom

15. In elevator systems, a device designed to stop a descending car or counterweight beyond its lowest limit of travel.
a. bumper b. buffer c. dumbwaiter d. hoist way

16. The minimum factor of safety for suspension wire rods with 1 500 feet per min (fpm) passenger elevator.
a. 7.6 b. 9.5 c. 10 d. 11.9

17. A closed vessel in which steam or vapor is generated at a pressure of more than 1.055 kg/cm2 gage by direct application of heat.
a. portable boiler c. locomotive boiler
b. miniature boiler d. power boiler

18. Method of testing boiler integrity that uses x-rays to generate & record on film the imperfections or defects in the boiler tube material & welds.
a. metallurgical replication c. vacuum testing
b. ultrasonic thickness gauging d. radiographic testing

19. In the fire protection, class of fire in ordinary combustible materials such as cloth paper, rubber & many plastics.
a. Class A b. Class B c. Class C d. Class D

20. An underground formation that contains sufficient saturated permeable material to yield significant quantities of water.
a. aquifer b. water table c. porous layer d. well

21. Pipe color for acetylene.
a. yellow b. green c. orange d. red

22. In metrology, it is a device used to determine whether the part has been made to the tolerance required and does not usually indicates a specific dimension.
a. bevels c. gage
b. dial indicator d. trammel

23. In manufacturing, process of making molds for the plastic and die casting industries.
a. intraforming c. infiltration
b. swaging d. hobbing

24. A copper-silicon alloy available in five slightly different nominal compositions for applications which require high strength, good fabricating, & fusing qualities.
a. inconel c. everdur
b. monel d. babbit

25. In instrumentation, it is a device whose function is to pass on information in an unchanged form or in some modified form.
a. programmable logic controller (PLC) c. pilot light
b. controller d. relay

SOURCE: THE PHILIPPINE MECHANICAL CODE (FORMERLY PSME CODE) CODE 2003 EDITION

More mechanical engineering board exam review materials on the succeeding posts. Please subscribe to receive alerts whenevel new reviewers are posted.

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