quiz abe 61 Flashcards
resist failure
strenght of material
resist deformation
stiffness
deformation due to external force is within certain limit
elastic limit
retain its original shape and size
elasticity
limit within which the body behaves perfectly elastic
elastic limit
resistance per unit deformation
stress
stress that is loaded by an axial force
normal stress
stress state leadíng to expansion
tensile stress
ability to deform under tensile stress
ductility
force that attempts to squeeze or compress a material
compressive stress
differs from tensile and compressive stresses in that the external and internal forces are parallel to the stressed crossed sectional area
shearing stress
stress developed when two elastic bodies are forced together
bearing stress
force acting on a generally horizontal direction
tangential stress
force that produce mountain folding and faulting
tangential stress
distance between the two reference points
gauge length
determined by dividing the elongation values by the gauge length
strain
stress is proportional to strain
proportional limit
material will not be able to recover its original size and shape
yield point
stress corresponding to yield point
yield point stress
stress which attains its maximum value
ultimate stress
necessary to break away the specimen, is less than the maximum stress
breaking stress
ratio of the maximum stress to the working stress
factor of safety
used to determine the combined effect of two or more stresses
superposition method
considered uniform, and will be the same value over the entire length of the beam
axial stress
accumulation of stress in a body due to sudden change in its geometry
stress concentration
to prevent a body from getting failed, the concentration of stress should be avoided or reduced
stress risers
ratio of highest stress in the body to the reference stress
stress concentration factor
one that performs well
successful product
have relatively high moduli
metals
can be made strong by alloying and by mechanical and heat treatment
metals
have high moduli, but unlike metals, they are brittle
ceramics and glasses
have moduli which are low, roughly 50 times less than those of metals
polymers and elastomers
they can be strong, nearly as strong as metals
polymers and elastomers
combine the attractive properties of the other classes of materials while avoiding some of their drawbacks
composites
light, stiff and strong, and they can be tough
composites
determined the behaviour of materials under the action of external forces called loads
mechanical properties of materials
determined by the range of usefulness of the metal and establish the service that is expected
mechanical properties of metals
useful for help to specify and identify the metals
mechanical properties
enables a metal to resist deformation load
strength
capacity to withstand destruction under the action of external loads
strength
ability of an object or material to resume its normal shape after being stretched or compressed
elasticity
power of coming back to its original position after deformation
elasticity
ability to undergo some permanent deformation without rupture
plasticity
resistance of a material to force penetration or bending
hardness
ability of material to resist scratching, abrasion, cutting or penetration
hardness
ability of material to oppose the scratches to outer surface layer due to external force
scratch hardness
ability of material to oppose the dent due to punch of external hard and sharp objects
indentation hardness
also called as dynamic hardness
rebound hardness
property of material which enables it to withstand shock or impact
toughness
opposite condition of brittleness
toughness
combination of strength and plasticity
toughness
enables it to withstand permanent deformation
brittleness
they will break rather than bend under shock or impact
brittleness
have high compressive strength but low in tensile strength
brittleness
resistance of a material to elastic deformation or deflection
stiffness
property of material which enables it to be drawn out into a thin wire
ductility
property of material which permits it to be hammered or rolled into sheets of other sizes and shapes
melleability
property of a solid body by virtue of which they resist from being broken into a fragment
cohesion
ability of metal to resist suddenly applied loads
impact strength
long effect of repeated straining action which causes the strain or break of the material
fatigue
slow and progressive deformation of a material with time at a constant force
creep
simplest type of creep deformation
viscous flow
those which contain iron
ferrous metals
those which contain no iron
non-ferrous metal
become misaligned, creating areas of weaknesses
dislocations
adding carbon to the iron
carbon steels
mixture of two or more chemical elements, and primary element is a metal
alloy
carbon content between 0.1% and 0.3%
mild steel
contains carbon between 0.3 and 0.7%
medium carbon steel
contains carbon between 0.7 and 1.3%
high carbon steel
chromium content between 13% and 27%
stainless steel
alloy of iron(94%), carbon (3%), silicon (2%)
grey cast iron
makes the alloy magnetic and improves elasticity
silicon
makes the alloy harder and heat resistant and used to make stainless steel
manganese
improves strength and prevents corrosion
nickel
makes the steel harder , more heat resistant, and prevents corrosion
tungsten
makes the alloy harder and tougher and more rustproof
chromium
most abundant metal in the earths crust and after steel
aluminum
worlds third most important metal in terms of volume of consumption
copper
covers a wide range of copper zinc alloys
brass
shiny and silvery white
magnesium
shiny white metal
tin
silvery grey metal
lead
alloy of copper and tin
bronze
bluish grey shiny metal
zinc
containing up to about 0.7% total impurities
copper
contain small amounts of various alloying elements such as beryllium, chromium, zirconium, and etc.
high copper alloys
copper zinc alloys containing up to about 45% zinc
brasses
alloys of copper with tin, plus atleast one of phosphorus, aluminum, silicon, manganese and nickel
bronze
alloys of copper with nickel with a small amount of iron
copper nickel
contain 55 to 65 percent copper alloyed with nickel and zinc
nickel silvers
creates complex shapes from molten metal
casting
creates a two piece sand mold around a pattern
sand casting
uses permanent molds into which low melt points metals
die casting
creates intricate wax patterns
investment casting
used to transform bulk materials in the form of billets
metal deformation
copper and aluminum are forced through dies to produce common shapes such as copper tubing or aluminum angles
extrusion
uses hydraulic die sets or open dies and hammers
forging
transforms mill products into finished raw materials
rolling
achieving higher yield strength and better surface finishes than hot rolling
cold rolling
used to further reduce bar stock
bar drawing
continous the process of bar drawing by pulling ductile materials
wire drawing
usually small and ductile enough that it can be wound onto spools of significant capacity
resulting wire
the parts are formed sequentially as they index through each station of the die
progressive forming die
gradually pushes the material into a die cavity
drawing
creates holes and slots where needed
punching
create tabs and other features that run perpendicular to the plane of the original material
bending
the finished part from the remaining coil material that has served to carry the forming part through the die
blanking shears
remove material from round and bar stock
machining
forming of both thermoset and thermoplastic materials
polymer processing
closed to force the material into the shape of the cavity
compression molding
heated polymer is injected into the closed mold
transfer molding
common method for making plastic bottle
blow molding
uses an auger to soften plastic pellets in a barrel
injection molding
shapes sheets or films of thermoplastic into cavities
thermoforming
used to produce large hollows shapes such as kayaks
rotomolding
often cast by pouring it into open silicon rubber molds
polyurethane
include plating, painting, sprue removing, polishing and etc.
finishing
important step in the finishing of many metal parts
heat treating
where the different parts that composed a finish product come together
assembly
instrumental in classifying, evaluating, and specifying the material, chemical, and mechanical properties of steels
astm steel standard
instrumental in specifying, testing, and assessing the physical, mechanical, and chemical properties of a wide variety of materials
astm plastic standard
ability of material to be worked or shaped into the finished component and is sometimes referred as “workability”
material evaluation and process selection
component or joint must have to function as required
performance requirements
ability to function as required over a specific use period
reliability requirements
