Machine Design Refresher

Question 1

Predicts the failure stress reasonably well for brittle materials under static biaxial loading

Answer 1

Maximum Normal Stress theory

Question 2

In the absence if friction, a simple machine is an ideal machine if the efficiency is

Answer 2

1

Question 3

Form of an inclined plane

Answer 3

Screw

Question 4

What is the Ideal Mechanical Advantage of the machine that changes only the direction of the input force?

Answer 4

1

IMA = Di/Do

Question 5

Ackermann steering gear is made up of

Answer 5

Turning Pairs

Question 6

What is the combination of applied normal and shear stresses that produces maximum principal normal stress or minimum principal normal stress, with a third principal stress betweeen or equivalent to the extremes?

Answer 6

Principal Normal Stress

Question 7

What is the other term for the Maximum-Shear-Stress Theory, as a failure prediction thoery?

Answer 7

Tresca Yield Criterion

MSS (3 letters = Tres-ca) Theory

Question 8

For a Kinematic Chain to be considered as mechanism:

Answer 8

One link should be fixed

Question 9

The motion of the shaft in a circular hole is an example of ____ motion

Answer 9

Incompletely Constraint

Question 10

The instantaneous center of rotation of a rigid thin disc rolling without slip on a plane rigid surface is located at:

Answer 10

The Point of Contact

Question 11

for a 4-bar linkage in toggle position, the value of mechanical advantage is:

Answer 11

Infinity

Question 12

It is a correction factor used to account for the non-uniform stress distributions

Answer 12

Stress Concentration Factor

Question 13

Fatigue Failure occurs when a part is subjected to:

Answer 13

Fluctuating Stress

(F)atigue = (F)luctuating

Question 14

A kinematic chain needs a minimum

Answer 14

4 Links and 4 Turning Pairs

Question 15

The total permissible variation in the size of dimension: the difference between the limits of size.

Answer 15

Tolerance

Question 16

the Total Deformation measured in the direction of the line of stress

Answer 16

Strain

Question 17

the maximum stress to which a material can be subjected without a trace of any permanent set remaining upon a complete withdrawal of the stress

Answer 17

Elastic Limit

Question 18

Which of the following steel with 0.3%-0.47% mean carbon content and has low-hardenability

Answer 18

SAE 1335

Question 19

Which of the following is a special type of nickel that is corrosion resistant and has high ductility and heat resistance

Answer 19

Low-Carbon Nickel

more ductile; less carbon

Question 20

In gramophones for adjusting the speed of the turn table, what type of governor is commonly used?

Answer 20

Pickering type

Question 21

A type of key which width and thickness are equal is called as:

Answer 21

Square Key

Question 22

Which of the following cannot be Poisson’s Ratio of material?

Answer 22

0.57

anything above 0.5 cannot be Poisson’s Ratio of material

Question 23

While designing a parallel sunk key, it is assumed that the distribution of force along the length of the key:

Answer 23

is Uniform Throughout

Question 24

What type of key that allows the hub to move along the shaft but prevents the rotation of the shaft?

Answer 24

Feather Key

Question 25

The *speed* at which the **center of mass will be equal to the deflecting forces of the shaft**; the shaft with its attached bodies **vibrate violently since the centrifugal force changes its direction** as the shaft turns in:

Answer 25

Critical Speed

Question 26

Which *type of key* is used for **mounting shifting gears in gear boxes**?

Answer 26

Splines

Question 27

It is *used for permanent fits* and **similar to involute splines** except that the **pressure angle is 14.5 deg**.

Answer 27

Involute **Serrations**

Question 28

What is the **maximum shaft angle** for a **single Hooke's Coupling**?

Answer 28

15 degrees

Question 29

**Universal Coupling** is:

Answer 29

Used for **non-collinear shafts**

Question 30

**Splines** are used when:

Answer 30

**Axial relative motion between shafts and hub** is necessary

Question 31

In bolts design, the **qoutient** of the **proof load** and *the tensile-stress area* is called:

Answer 31

**Proof** Strength

Question 32

It is the *distance in inches* a screw thread (**a helix) advances axially in one turn**:

Answer 32

Lead

Question 33

In *bolts design*, **proof strength** corresponds approximately **how many percent of the 0.2 percent offset yield strength**?

Answer 33

90% ## Footnote pag naay 0.2, 0.9 matic ???

Question 34

What *type* of blot **threaded on both ends** and **can be used where a through bolt impossible**?

Answer 34

**Stud** Bolt

Question 35

What *type* of bolt **distinguished by a short portion of the shank underneath the head** *being square or finned or ribbed*?

Answer 35

**Carriage** Bolt ## Footnote Shank underneath the head kay square, ribbed, finned

Question 36

The **Crest diameter** of a *screw thread* is the same as:

Answer 36

**Major** Diameter ## Footnote Major = Nominal = Crest

Question 37

A *tool bit for cutting* an **Americal National Thread** should be ground with an **angle** of:

Answer 37

60 degrees ## Footnote tan(30) = (p/2)/h

Question 38

The **Maximum Efficency** of **Self-Locking Screw** is:

Answer 38

0.5

Question 39

Which of the following *screw thread* is adopted for **power transmission in either direction**?

Answer 39

**ACME** thread

Question 40

These *clutches* **produce positive coupling** between the two shafts, *regardless of direction of rotation*.

Answer 40

**Jaw** Clutches

Question 41

**Herring Bone gears** are gears which:

Answer 41

Have a **line of contact between the teeth**

Question 42

In **usual spur gearing**, which of the following statement(s) is correct?

Answer 42

*Tooth outlines* are usually **Involute Curves**

Question 43

A *gear* is one in which **angle is 90 degrees** that is **pitch cone has become a plane**

Answer 43

Crown Gear

Question 44

What *type of gears* are used for **shaft axes having an offset**?

Answer 44

**Hypoid** Gear

Question 45

One of the causes of s*pur gear tooth breakage* is the unbalanced load on one of the tooth that results in higher stresses than when the load is evenly distributed. To minimize this problem, the **face width (b) should not be greater than the thickness (or Pitch) of the tooth**. In the absence of test values, the following can be a guide:

Answer 45

2.5**Pc** < b< 4**Pc**

Question 46

What *type of gear* which can **transmit power** at a **certain angle**?

Answer 46

**Bevel** Gear ## Footnote pag i-rotate and "v" sa bevel gear kay symbol sa angle

Question 47

It is used to **change rotary motion to reciprocating motion**

Answer 47

**Rack** Gear | **R**ack = **R**otary to **R**eciprocating

Question 48

In *gear design*, the *ratio of the pitch diameter* in **inches** **to the number of teeth**.

Answer 48

**English** Module

Question 49

Gear used to **transmit power at high velocity ratios** between **non-intersecting shafts** that are **ususally** but not necessarily at **right angle.**

Answer 49

**Worm** Gear

Question 50

For **evenly distributed and uniform wear** on each meshing gear tooth, the *ideal design practice* is to consider a:

Answer 50

**Hunting** Tooth Addition

Question 51

It refers to the **surface** of the gear **between the fillets of adjacent teeth**

Answer 51

**Bottom** Land

Question 52

If a set of **spur gears are made installed and lubricated properly**, they normally may be **subjected to failures like**:

Answer 52

**Pitting**

Question 53

In designing **gears for power transmission**, consider an **efficiency** of ____ as recommended

Answer 53

**98%** or more

Question 54

The *design of gear* on account of **Spott's equation which account for dynamic load is based on**:

Answer 54

**contact stress** based on **Hertz Theory**

Question 55

For a **proper design** and longer gear life:

Answer 55

**wear load must be more** than the dynamic load

Question 56

The **train value of gear train** is

Answer 56

**Reciprocal** of speed ratio ## Footnote makita ang train value sa tooth ratio

Question 57

the **gear train** usually employed in **clocks** is a:

Answer 57

**reverted** gear train

Question 58

A **reverted gear train** is one in which the **output shaft and input shaft**:

Answer 58

are **coaxial**

Question 59

In a **simple gear train**, if the **number of idler gears** is **odd**, then the **direction of motion of driven gear** will

Answer 59

be **same as that of the driving** gear

Question 60

in case of *spur gears*, the **flank of the tooth** is:

Answer 60

the *part of the tooth surface* **lying below the pitch surface**

Question 61

Which of the following statement(s) is correct for an **oilness bearing**?

Answer 61

**Do not need external** supply of **lubricant**

Question 62

It is the ability to deform plastically **to compensate for irregularities** in bearing assembly.

Answer 62

**Conform**ability

Question 63

a bearing that **permits constrained relative motion of rigid parts**; **lubricant is generally inserted or supplied between the mating surfaces** to reduce friction and wear, and to carry away the heat generated

Answer 63

**Sliding Contact** Bearing

Question 64

In practice and theory, what is the **allowed permissible misalignment in cylindrical and tapered** roller bearings?

Answer 64

**0.001** rad

Question 65

in practice and theory, the **misalignment of spherical bearings** should not exceed how many radians?

Answer 65

**0.0087** rad

Question 66

to **avoid scoring in the bearing surface** and the shaft due to contamination or absorption of the fine dirt in the bearing during operation/lubrication the **bearing material should have good ___ properties**

Answer 66

**Embed**dability

Question 67

a general rule of thumb for **cast-iron rim flywheels** of average size is that the **mean velocity should not exceed**:

Answer 67

**6000** fpm

Question 68

if the rotating mass of a rim-type flywheel is distributed on another rim-type flywheel **whose mean radius is half the mean radius of the former**, then **energy stored in the latter at the same speed will be**:

Answer 68

**one-fourth** of the first one

Question 69

in which one of the following is a **flywheel** generally employed?

Answer 69

**punching machine**

Question 70

the **rim of the flywheel** is subjected to:

Answer 70

**direct tensile stress** and **bending** stress

Question 70

**spring back metal forming** depends on ___

Answer 70

**modulus of elasticity**

Question 71

what is the **best method** for **increasing a spring's fatigue life**?

Answer 71

**shot peening** ## Footnote SHOT PUNO!!! = maka-increase og life chariz

Question 72

these springs are **made from one or more flat strips** of brass, bronze, steel, or other materials loaded **as cantilevers or simple beam**.

Answer 72

**leaf springs**

Question 73

the maximum shear stress occurs on the outermost fiber of a circular shaft under torsion. in a **close-coiled helical spring**, the **maximum shear stress** occurs on the:

Answer 73

**innermost** fiber

Question 74

the **Compliance** of the spring is the:

Answer 74

**Reciprocal of the spring constant**

Question 75

there are two basic types of *torsion springs*, one of which is the **flat coil spring** also known as **power spring or**:

Answer 75

**clock** spring ## Footnote flat; power(ful) = c(l)ock skdjgfjhsdghj

Question 76

recommended **speed for leather belt**:

Answer 76

**7000 - 8000** fpm ## Footnote LEATHER has 7 letters (7000 + 1000)

Question 77

recommended **speed for fabric belts**

Answer 77

**4000 - 5000** fpm

Question 78

what is usually the **lose factor** for most **wire ropes and chains** with **180deg contact at low speeds**

Answer 78

varies from **1.03 to 1.06**

Question 79

based on experience, what is the **most economical design belt speed**?

Answer 79

**6000 - 7500** fpm