ENGM 445 FINAL EXAM QUESTIONS AND ACCURATE ANSWERS A+ RATED

ENGM 445 FINAL EXAM QUESTIONS AND ACCURATE
ANSWERS A+ RATED



Which two of the following are purposes of finishing operations such as grinding used for
parts made of the new ceramics?

apply a surface coating

electroplate the surface

improve surface finish

increase dimensional accuracy - ANSWER improve surface finish

increase dimensional accuracy




A roving is a collection of twisted continuous strands, whereas a yarn is an untwisted

collection of filaments. T o F - ANSWER False




Of the open mold processes for polymer matrix composites, hand lay-up is the least
labor-intensive. T o F - ANSWER False




In the hand lay-up process, a dry layer of fiber reinforcement is placed onto the mold and
impregnated by liquid uncured resin using a manual rolling technique; the process is repeated
for successive layers. T o F - ANSWER True




Automated tape-laying (ATL) machines dispense a prepreg tape onto an open mold by
following a programmed series of back-and-forth passes across the mold surface until the

,parallel rows of tape complete each layer. T o F - ANSWER True




The principal process parameters in curing (cross-linking) of the thermosets used in
fiber-reinforced polymer composites are time, temperature, and pressure. T o F - ANSWER

True




Resin transfer molding is a closed-mold process in which a preform mat is placed in the mold
and a thermosetting resin is transferred into the cavity under moderate pressure to
impregnate the preform. T o F - ANSWER True




Although thermoplastic fiber-reinforced plastics can be injection molded, thermosetting FRPs
cannot be injection molded because of the risk of premature cross-linking in the injection
chamber. T o F - ANSWER False




Pulforming is similar to pultrusion but is capable of producing a semicircular contour with
altered cross sections at one or more locations along the length of the part. T o F - ANSWER
True




The term prepreg stands for which one of the following? - ANSWER pre-impregnated fibers




An advantage of using an open mold versus a closed mold is which one of the following? -
ANSWER the mold costs much less than if two matching molds were used




Which two of the following products are not made by hand lay-up open-mold operations?

,Boat hulls

Fishing Polls

Larger Container tanks

Swimming pools

Tennis Rackets - ANSWER Fishing Polls

Tennis Rackets




In the spray-up method, liquid resin is applied on an open mold and chopped fibers are then
sprayed onto the resin to build successive FRP laminations. T o F - ANSWER False




An apparatus that provides control over both temperature and pressure and is used to cure
polymer matrix composites is called which one of the following? - ANSWER Autoclave




A molding operation that uses sheet-molding compound is a form of which one of the
following? - ANSWER compression molding




Filament winding involves the use of which one of the following fiber reinforcements? -
ANSWER continuous filaments




The special tooling in filament winding that determines the shape of the filament-wound part

is called which one of the following? - ANSWER mandrel

, The most important rubber product is which one of the following? - ANSWER pneumatic tires




The name of the natural rubber sheets that have been dried in smokehouses is which one of
the following? - ANSWER ribbed smoked sheet




Of the following additives in rubber, which one would rank as the single most important? -
ANSWER carbon black




The roller die process is a combination of which two of the following processes?

calendering

casting

coating

extrusion

molding

shearing - ANSWER Calendering

Extrusion




The internal structure of the tire, consisting of multiple layers of rubber-coated cords, is called
which one of the following? - ANSWER carcass




When is the tread pattern imprinted onto the circumference of the tire ? - ANSWER during
molding