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WorksheetsQuiz 7b
Total questions: 60
Worksheet time: 30mins
According to the figure showing (a) tensile, (b) compressive, (c) flexural (bending), (d) torsion, and (e) shear forces, which force corresponds to bending of a beam-like specimen?
Flexural force
Tensile force
Compressive force
Shear force
When a force is applied on a solid material, what is the material’s response as stated in the fundamentals of deformation?
It deforms in response to the force
It remains unchanged regardless of force
It instantly melts
It becomes more crystalline
The diagram shows a cylindrical bar with arrows pushing inward from both ends. What type of force is being applied?
Compressive force
Tensile force
Torsion force
Shear force
Extension by stretching is described as the simplest type of deformation in the tensile fundamentals. What does extension involve?
Deformation by stretching
Deformation by twisting
Deformation by compressing
Deformation by shearing
A mechanical test that uses tensile forces is called what?
Tensile test
Hardness test
Compressive test
Shear test
In tensile testing, what is meant by tensile strength?
The stress needed to break a sample
The elongation at yield
The force required to bend a sample
The modulus of elasticity
Which units are appropriate for expressing tensile strength, as noted in the tensile fundamentals?
Pascal-based units such as MPa, GPa, or N/mm^2
Kelvin
Decibel
Joule
In measuring elongation during a tensile test, the portion of the narrowed section of the sample over which it is measured is termed what?
Gauge length
Cross-sectional area
Yield region
Grip length
Which instrument is used to determine elongation and tensile modulus in a tensile test?
Extensometer
Micrometer
Dynamometer
Caliper
Refer to the diagram of a tensile specimen before and after testing with gage markings. In the stressed sample, what is the distance between the gage markings indicated in the figure?
2in
2.65in
8in
1in
In the same tensile specimen diagram, what gage length is indicated for the unstressed sample before testing?
1in
2in
2.65in
8in
Based on the arrows labeled F acting on the specimen ends, which type of loading is applied in the diagram of the tensile specimen before and after testing?
Compressive
Torsional
Shear
Tensile
According to the ASTM D 638 composite sample drawing, what overall specimen length is shown?
25mm
250mm
2.5mm
100mm
In the ASTM D 638 composite sample drawing, what thickness is specified at the edge detail?
0.8mm
2.5mm
25mm
5mm
In image a of the composite samples slide, what test setup is shown holding a strip specimen?
Three-point bending fixture
Vickers hardness indenter
Tensile grips in a universal testing machine
Charpy impact pendulum
In the dumbbell specimen diagram labeled Before loading and After fracture, which region is identified as undergoing the localized reduction in cross-section during tensile testing?
Grip section
End tabs
Necked-down region
Gauge shoulder fillet
Which structural factors listed determine the tensile behavior of polymers? Select all that apply.
Average molecular weight
Degree of crystallization
Effect of highly polar atoms on the main chain
Presence of phenyl rings in the main chains
Processing temperature during moulding
According to the final slide, ADMET is associated with which field?
Pharmaceutical dosing equipment
Materials testing systems
Microelectronics design services
Environmental monitoring sensors
Performing Test: According to the flexural test method described, what behavior does this method measure for materials subjected to simple beam loading?
Resistance to surface abrasion
Behavior under bending loads
Thermal expansion rate
Electrical conductivity under stress
Performing Test: How is the simple rectangular beam specimen positioned and loaded in the flexural test described?
Clamped at one end and pulled in tension at the free end
Suspended by cables and impacted at one corner
Placed over two supports and loaded at the middle between the supports
Bonded to a plate and compressed uniformly across its surface
Performing Test: In the illustrated three‑point bending apparatus, where is the load applied to the specimen relative to the supports?
Directly above the left support
At the midpoint between the two supports
Directly above the right support
At an off‑center point near one end
Brand Reference: Which web address is shown for the materials testing systems brand displayed?
www.ADMET.com
www.ADMIT.com
www.ADAMET.com
www.AMDET.com
Strengthening of Polymers: Which factor increases strength up to a certain critical mass?
Average molecular mass
Sample thickness
Cooling rate after processing
Ambient humidity
Strengthening of Polymers: Which change increases strength, modulus of elasticity, and density?
Decrease in crystallinity
Increase in crystallinity
Addition of plasticizer
Reduction in chain entanglement
Strengthening of Polymers: What modification can hinder chain slippage during permanent deformation?
Shortening the main carbon chain
Introducing pendant atomic groups to the main carbon chain
Removing all polar atoms from the backbone
Increasing porosity
Strengthening of Polymers: Which approach increases strength by bonding on the main carbon chain?
Bonding highly polar atoms
Bonding nonpolar inert gases
Removing functional groups
Adding voids through foaming
Deformation Mechanism (Semicrystalline polymers, T greater than Tg): Which stage is described as NECK forms and grows unstably, i.e., inhomogeneous plastic deformation?
I
III
V
VIII
Deformation Mechanism (Semicrystalline polymers, T greater than Tg): Which stage corresponds to COLD DRAWING, where the neck increases in length by extracting polymer from the unnecked region?
II
IV
V
VII
Deformation Mechanism (Semicrystalline polymers, T greater than Tg): At which stage does fracture occur?
I
VI
VII
VIII
Stages and Mechanisms of Plastic Deformation: Which listed stage describes rotation/tilting of lamellae crystallites toward the tensile axis?
Elongation of amorphous chains
Rotation/tilting of lamellae crystallites toward tensile axis
Separation of crystallites into block segments
2nd strain hardening regime
Stages and Mechanisms of Plastic Deformation: Which stage involves separation of crystallites into block segments due to partial melting?
Stage 1
Stage 3
Stage 4
Stage 5
Stages and Mechanisms of Plastic Deformation: In the 2nd strain hardening regime, what microstructural change is described?
Randomization of chain orientation leading to softness
Recrystallization to a fiber‑like oriented structure with high stiffness
Void formation and stress whitening without orientation
Complete melting of all crystalline lamellae
In the semi-crystalline polymer deformation diagram, the sequence of microstructural changes under increasing strain is shown below the stress–strain plot. Which change occurs immediately before the stage labelled crystalline regions slide?
Amorphous regions elongate
Crystalline regions align
Onset of necking
Near failure microvoiding
According to the deformation mechanism figure, the aligned, networked cross-linked case follows a high-stress path that ends in brittle failure. Which failure mode is associated with this case?
Plastic failure
Brittle failure
Creep rupture
Fatigue failure
The semi-crystalline case plot shows an unload/reload path during deformation. What does the presence of this path indicate about the material response in that region?
Purely elastic behavior without hysteresis
Viscoelastic or plastic behavior with hysteresis
Immediate brittle fracture upon unloading
Creep at zero stress
In the elastomer deformation diagram, the green curve labelled elastomer rises gently with strain, and annotations state deformation is reversible. Which description best matches the initial microstructure of the chains?
Straight and uncross-linked
Kinked and heavily cross-linked
Crystalline lamellae aligned
Broken and entangled without cross-links
For the elastomer curve, the annotation says deformation is reversible. What does the final chain configuration look like according to the diagram?
Chains remain kinked and uncross-linked
Chains are straight and still cross-linked
Chains form crystalline lamellae that slide
Chains fracture at the yield point
In the schematic of elongation experiment for an amorphous polymer at room temperature, the stress–strain curve is marked A, B, C, D alongside sample silhouettes. Which stage corresponds to the formation of a localized neck?
A
B
C
D
In the amorphous polymer elongation schematic, how does stress behave between A and B on the stress–strain curve?
Increases approximately linearly with strain
Remains nearly constant over strain
Decreases linearly with strain
Oscillates around a mean value
In the polymer stress–strain diagram, which labelled point marks the onset of yield?
A
B
C
D
E
Between A and C on the stress–strain diagram, the material follows a straight-line relation. Which law describes this region?
Hooke’s Law (linear elasticity)
Newton’s Law of viscosity
Griffith’s fracture criterion
Fick’s First Law of diffusion
At C on the stress–strain curve, the caption notes the actual curve deviates from the straight line. What is this limit called?
Elastic limit
Proportional limit
Ultimate strength
Fracture toughness
On the stress–strain diagram, which labelled point corresponds to break?
B
C
D
E
The stress–strain behaviour slide describes the A–B interval. Which statement best characterizes deformation in A–B?
Permanent displacement of molecules dominates
Relatively small, instantaneous, recoverable deformation
Straightening of coiled chains without intermolcular slippage
Molecular slippage with irreversible displacement
Beyond C on the stress–strain behaviour slide, which process is highlighted?
Intermolecular slippage causing permanent deformation
Straightening of coiled portions of molecular chains without intermolecular slippage
Formation of crystalline lamellae and immediate fracture
Elastic unloading with no microstructural change
Which region is identified as not recoverable, involving actual displacement of molecules with respect to each other?
A–B
Beyond C
Beyond D
A–C only
Using the diagram titled "General types of tensile stress-strain behavior in polymers," identify which labeled curve corresponds to Low Modulus, Weak Materials with Low Toughness. Select the correct curve label.
a
b
c
d
Using the diagram titled "General types of tensile stress-strain behavior in polymers," identify which labeled curve corresponds to High Modulus, Strong Materials with Low Toughness. Select the correct curve label.
a
b
c
d
Using the diagram titled "General types of tensile stress-strain behavior in polymers," identify which labeled curve corresponds to High Modulus, Strong and Tough Materials. Select the correct curve label.
a
b
c
d
Using the diagram titled "General types of tensile stress-strain behavior in polymers," identify which labeled curve corresponds to Low Modulus, Strong and Tough Materials. Select the correct curve label.
a
b
c
d
Refer to the diagram of typical load–elongation behaviour of LDPE. What event occurs immediately after the maximum load is reached on the curve?
Neck forms and grows along the specimen
Material fractures at the grip without necking
The specimen returns to its original shape elastically
Uniform strain hardening occurs without necking
In the five steps of deformation mechanism in polyethylene, which step is described as COLD DRAWING where the neck increases in length?
I
II
III
IV
V
In the five steps of deformation mechanism in polyethylene, which step corresponds to Near failure/ strain hardening?
I
II
III
IV
V
In the five steps of deformation mechanism in polyethylene, which step denotes Failure/ Fracture?
I
II
III
IV
V
On the Rubber Modulus slide, what does M100 represent?
Tensile stress at 100% elongation
Young’s modulus at zero strain
Tensile strength at break
Secant modulus at 300% elongation
On the stress–elongation curve for a rubber compound, what does the vertical dashed line labeled Elongation At Break (%) indicate?
The strain at which the specimen ruptures
The load at yield
The modulus measured at 300% strain
The percentage of elastic recovery after unloading
From the list of important terms associated with stress–strain behaviour, which term denotes the maximum stress reached on the curve?
Yield Point
Proportional limit
Modulus of Elasticity
Ultimate Strength
From the important terms listed, which term is the slope of the initial linear portion of the stress–strain curve?
Modulus of Elasticity
Secant Modulus
Yield Point
Elongation
In the general types of tensile stress–strain behaviour in polymers figure, which region corresponds to non-recoverable deformation after yielding?
Elastic Region
Plastic Region
Ultimate Elongation
Point of Rupture
In the same figure, what is indicated by Yield Elongation?
The strain at which yielding occurs
The maximum strain before rupture
The elastic recovery after unloading
The minimum stress measured at yield
