Explain the phenomenon of (a) Creep and (b) Relaxation in
materials. Show stress versus time and...
Explain the phenomenon of (a) Creep and (b) Relaxation in
materials. Show stress versus time and strain versus time response
for both phenomena. How will you calculate the creep and relaxation
modulus?
Choose the best option:
- Viscoelastic stress relaxation
- Viscoelastic creep
Although the viscoelastic response of a polymer can be very
complex (time-dependent stress cycling for instance), two special
loading scenarios are fairly simple to describe mathematically.
1. _______ refers to scenarios for which the stress applied to a
polymer must decay over time in order to maintain a constant
strain. Otherwise, over time, the polymer chains will slip and
slide past one another in response to a constant applied...
Glass Science -- Stress Relaxation : please show calculation in
detail or with explanation:
1] a) Show, by calculation, how much time is required to relax
90% of the stress in a glass at the annealing point; the initial
stress is 300 MPa, the temperature is 535C, the elastic modulus is
55 MPa, the shear modulus is 10 GPa and Poisson’s ratio is 0.3
b) What about at the strain point ?
c) What about at the softening point where...
Why T1 relaxation time is temperature dependent?
Why T2 relaxation time is temperature dependent?
Explain it with theory.
These are complete questions. If you don't understand the
questions, you are not qualified to answer them.
Show the qualitatively correct position versus time graph and
the matching velocity versus time graph for an object that passes
through the point X0 = -1 m at t0 = 0 s, and speeds up in the
negative X-direction until it reaches a constant speed at tA.
Between tA and tB, the object maintains this speed. At tB the
object slows down and makes a momentary stop at tC, and immediately
resumes the motion in the opposite direction (show a...
The tabulated data show the concentrations of N2O5 versus time
for this reaction: N2O5 (g) --> NO3 (g) + NO2 (g).
Time(s)
[N2O5] (M)
0
1.000
25
0.822
50
0.677
75
0.557
100
0.458
125
0.377
150
0.310
175
0.255
200
0.210
1a. Determine the order of the reaction by graphing:
Zero Order: Time vs [N2O5]
First Order: Time vs ln[N2O5]
Second Order: Time vs 1/[N2O5]
1b. Determine the rate constant
1c. Predict the concentration of N2O5 at 250 seconds.
The tabulated data show the concentrations of N2O5 versus time
for this reaction: N2O5 (g) --> NO3 (g) + NO2 (g).
Time(s)
[N2O5] (M)
0
1.000
25
0.822
50
0.677
75
0.557
100
0.458
125
0.377
150
0.310
175
0.255
200
0.210
1a. Determine the order of the reaction by graphing:
Zero Order: Time vs [N2O5]
First Order: Time vs ln[N2O5]
Second Order: Time vs 1/[N2O5]
1b. Determine the rate constant
1c. Predict the concentration of N2O5 at 250 seconds.
The following reaction was monitored as a function of time:
A→B+C A plot of ln[A] versus time yields a straight line with slope
−4.0×10−3 /s .
Part D If the initial concentration of A is 0.220 M , what is
the concentration after 230 s ?
[A] = m M