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Assignment Topics

MSE302A: Mechanical Behavior of Materials

(2021-2022) Odd semester

Due:

31 October, 2021.

Submission:

A report (max. 5 pages) and a video (max: 5 min)

Contact:

Instructor:

Niraj Chawake (nchawake@iitk.ac.in)

TAs:

Pulkin Gupta (pulkin20@iitk.ac.in)

Shirish Chandrakar (ishirishch20@iitk.ac.in)

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Topic 1: Measuring strains using digital image correlations

Team members:

180198 190275 190497 190501

The Digital Image Correlation (DIC) is technique that is used for accurate displacement and

strain measurement. The basic principle of this techniques involves capturing multiple digital

images during deformation using digital camera and then matching and analyzing these images

with each other using statistical and continuum mechanics principles. we find displacement/

strain.

LePage W. A Practical Guide to DIC

In above figure, we can find the strain by comparing the reference state and deformed state by

analyzing the changes occurring in pattern.

In this assignment, you need to explain how we measure the strains using DIC technique. You

may include introduction about DIC, principle, experimental setup, correlation algorithm,

advantages and challenges of this method etc. for strain measurement.

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Topic 2: Device/clothing design to avoid hip fracture

Team members:

190637 190554 190341 180474

Most of the elderly people are vulnerable to hip fracture when they accidently fall/slip. Either

they get seriously injured which has lower chances of recovery leading to a permanent

disability or even fatality.

We will be looking this problem in a mechanics point of view. We know that fracture happens

when a sufficient amount of energy is imposed on a material causing breaking of bonds and

creating new surfaces. The fracture resistance of materials is measured in terms of critical strain

energy release rate (Gc) and critical stress intensity factor (Kc). Another parameter (Jc) using

J-integral indicates fracture toughness. Jc for bone is 2-7 mJ/mm2.

We are intended to design a device or clothing which absorbs the impact energy during free

fall/side fall, so as to avoid fracture of bone or joints?

Refer following articles to get more ideas

https://www.sciencedirect.com/science/article/pii/002192909400069G

https://www.hindawi.com/journals/bmri/2015/413839/

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Topic 3: Forces in bicycle members. Why bicycle remains stable while moving?

Roll No:

190551 190680 190734 190989

https://img.freepik.com/free-vector/flat-infographic-structure-multi-speed-bike_238578-

1137.jpg?size=626&ext=jpg

The above figure shows a basic structure of bicycle. Each structure experiences a certain force.

The physics of these forces makes the bicycle move. An example of force experienced at pedal

and chain is given in figure below. Apart from this there are other external force experienced

by bicycle.

https://www.real-world-physics-problems.com/bicycle-physics.html

In this assignment, you have to explain what all forces are experienced by different member of

bicycle and explain mechanics related to that.

Also, you need to explain the reason behind why bicycle remains stable while riding and

become unstable as it comes to still?

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Topic 4: Water bottles for subzero temperatures

Roll No:

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We can use insulating bottles to store water under subzero temperature. However, we can’t

provide this insulation for a long time. We know that the freezing point of water decreases with

increase in pressure. This is because water expands when it freezes. When water is freezing, it

will expand and exert a pressure on the inside body of a bottle.

Can we device a water bottle which can exert a back pressure on water when it starts freezing?

The back pressure created can remelt the ice and thus avoid any freezing? Thus, explain what

are the stresses a bottle experience when water transforms to ice?

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Topic 5: Kite Aerodynamics:

Roll No:

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We all have seen kites flying in open sky but have rarely thought about how do kites really fly.

Generally, Kites have three main components:

1) Kite body

2) Bridle

3) Control line

https://airandspace.si.edu/stories/editorial/how-kites-fly

When kite is in flight it experiences number of forces like lift, drag, thrust, etc. Also, this force

depends on factors like kite design. To have a stable flight the force should be balanced, and

stable equilibrium should be maintained.

In this assignment, you need to discuss about the aerodynamics of kite. Explain stress

distribution when kite is flying.

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Topic 6: Device to send signals when trapped in avalanche

Roll No:

190394 190750 190692 190532

You might remember 2016 Siachen Glacier avalanche tragedy when a soldier was buried under

35 feet snow. He was found alive after the sixth day, unfortunately shortly he succumbed to

death after he was rescued.

The snow depth can create a pressure, also, someone trapped in snow can experience huge

temperature drop. Thus, can we make a device which sense a pressure and temperature

difference and sends signals to a rescue-team to expediate rescuing operations?

In this assignment, think in terms, what can be the pressure increase due to snow accumulation

when get trapped in avalanche?

https://en.wikipedia.org/wiki/2016_Siachen_Glacier_avalanche

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Topic 7: T4 bacteriophage-Martensite transformation:

Roll No:

190085 190122 190852 180270

This virus consists of a DNA-filled icosahedral head or capsid attached to a tail assembly

composed of a cylindrical sheath surrounding a narrow tubular core. At the end of the tail is a

hexagonal baseplate from which extend six long and six short tail fibres. The virus head is a

two-dimensional protein crystal which closes on itself because of a periodic array of

disclinations. The tail sheath is also a two-dimensional protein crystal which closes to form a

cylinder. When the virus tail contacts a bacterium, attachment of the tail fibres to the bacterial

cell wall transforms the baseplate from the hexagonal to a "star-shaped" form. This in turn

triggers a transformation in the tail sheath involving a contraction which drives the rigid core

through the bacterial cell wall, injecting the virus.

Olson, G. B., and H. Hartman. "Martensite and life: displacive transformations as biological

processes." Le Journal de Physique Colloques 43.C4 (1982): C4-855.

Due to change in structure during contraction, the spacing decreases, annular rotation increases,

outer diameter increases. There causes relatively large deformation (expansion and contraction

) along principal axis.

In this assignment, you have to find lattice deformation (stress and strain) associated due to

tail contraction.

You can go through this link to get better idea: https://hal.archives-ouvertes.fr/jpa-

00222128/document

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Topic 8: Honeycomb structure deformation:

Roll No:

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Honeycomb structures have been widely used in kinds of industrial applications like aerospace

and automobile industries, due to their excellent mechanical performance and high-energy

absorption capacity. The below image shows honeycomb structure.

Wang, Zhonggang, et al. "Deformation mode evolutional mechanism of honeycomb structure

when undergoing a shallow inclined load." Composite Structures 147 (2016): 211-219.

For your assignment, you need to discuss how this structure deforms when load is applied to

it. This load can be applied at different axis.

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Topic 9: Chandrayan: Vikram’s crash landing

Roll No:

190612 190278 190262 190311 190474

I am sure, you must have been there when the Chandrayan Vikram crash landing happened. At

the time of crash landing, we can calculate the kinetic energy (KE) that lander would have had

Details: Mass 1471 kg (source: wiki)

Last velocities reported

Horizontal component = 48.1 mps,

Vertical component Vv = -59 mps, Altitude 0.335 km, 1.09 km left before touch down. (Source:

Live telecast by DD National)

Lander moving at an angle of 51° with moon surface.

KE of lander = 4242.392 kJ*

(*Please cross-verify this data and check the calculations)

We know that the lander did not survive after the impact. Thus, out of curiosity, can we design

lander legs to sustain such impact? Can we use some materials which can absorb this large

energy and undergo only elastic deformation? Or can we make sacrificial leg assembly which

can absorb the impact energy and thus can save the lander?

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Topic 10: Deformation of Scutoids

Roll No:

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You might have seen the arrangement of seeds in pomegranate. Each seed is a scutoid (a

structure which you might have not paid attention). Please check the following link for more

information.

https://www.youtube.com/watch?v=2_NZ1ql8B8Y

https://www.nature.com/articles/s41467-018-05376-1

https://www.usatoday.com/story/news/nation-now/2018/07/30/spanish-scientists-discover-

new-geometry-shape-scutoid/864524002/

For your assignment, consider two scutoid-cells joined together. Find the stress states on each

surface and the location of the plane experiencing a maximum strain?

Image courtesy: https://www.newyorker.com/science/lab-notes/we-are-all-scutoids-a-brand-

new-shape-explained

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Topic 11: Movement of Tectonic plates

Roll No:

190088 190252 190653 190656

Tectonic plates move very slowly (0-100 mm/year). Thus, there movements get unnoticed.

However, such movement with time get accumulated and causes catastrophe such as

earthquake. This time dependent deformation is called creep.

For your assignment, can you tell us tectonic movement of the Indian plate? Thus, elaborate

more clearly what are the underlying mechanisms and phenomena for tectonic movements.

https://en.wikipedia.org/wiki/Indian_Plate

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Topic 12: Height of mountains on Venus

Roll No:

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In Venus, high mountain cannot exist for an appreciable time period. This is due to the presence

of rock with weaker creep strength. This is due to presence of small amount of water in Venus,

the wet rocks creeps faster at high temperature than dry rocks. This creep flow reduces the

height of the mountain and balances the increase in elevation due to active tectonic and volcanic

process, keeping the height of mountain roughly constant.

In this assignment you need to discuss the creep effect that occur in rocks of Venus which in

turn effect the height of the mountain.

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Topic 13: Kanishka crash mystery solved by metallurgist

Roll No:

190635 190951 190101 190092

Kanishka, Air India’s Boeing 747, disintegrated in mid-air on June 23,1985 while passing

through the Irish airspace. Nobody could guess what happened to the plane in mid-air and

multiple speculations were made until Dr. V. Ramachandran, an IISc alumus, found some

fragments of structural elements used to support the fuselage of the aeroplane. The aluminium

tube was supposed to carry vital information of the crash and was subsequently examined to

have been fractured and curled inwards.

For a better insight, please check this report by The Wire:

https://thewire.in/science/metallurgy-helped-expose-terrorists-hand-1985-kanishka-crash

For your assignment, study what kind of stresses and strain were responsible for a such a

catastrophic deformation? Also, clearly discuss what can be microstructural evolution and its

linkage to mechanical behavior of materials under such catastrophic deformations.

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Topic 14: Deformation of Living tissue and their implications in tissue engineering

Roll No:

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Mechanical properties and behaviour of living tissues are of great importance in studying their

growth and repair. Thus, it has been established that engineering tissues require integration and

approximation of both static and dynamic mechanics.

Please check the following links for more information:

https://www.nature.com/articles/s41578-019-0169-1?proof=t

https://royalsocietypublishing.org/doi/10.1098/rsob.210006

For your assignment, you are required to discuss the stresses and strains that are developed in

tissue as they grow and repair.

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Topic 15: Water surface tension and biomimicking water striders

Roll No:

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You must have seen water striders i.e., water walking insects. They use surface tension of water

to walk freely. Can we biomimick these water striders? Thus, you need to device a robot which

can walk on water. How can you do the balancing of forces for this robot; so as; it also uses

surface tension of water to walk freely?

https://en.wikipedia.org/wiki/Gerridae

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Topic 16: Radiation damage of structural alloys

Roll No:

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When structural alloys are irradiated with high energy particles, atoms of the alloy are displaced

from their lattice positions and hence, certain defects like vacancies or interstitials are

generated. These defects continue to grow on continued irradiation and ultimately lead to

changes in the microstructure of the structural alloy. The changes in microstructure have

significant effect on the mechanical behaviour of these structural alloys.

For your assignment, discuss the changes in the microstructural behaviour and its effect on the

mechanical behavior of these structural alloys.

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Topic 17: Mechanical behaviour of CNTs

Roll No:

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Carbon Nano Tubes (CNTs) are known to possess extraordinary mechanical and electrical

properties. They continue to grow as one of the most popular material used for reinforcements

of composites owing to such unique properties. These properties exist only in case of perfectly

crystalline CNTs and their strength drops abruptly when defects are introduced into them.

For Example, when CNTs are bent, they behave like drinking straws, they buckle and their

bending strength drops abruptly.

For reference on structure and mechanical properties of CNTs, you may follow:

https://utw10193.utweb.utexas.edu/Archive/RuoffsPDFs/117.pdf

For your assignment, discuss the stresses and strain developed on various surfaces of CNTs

that lead to drop in strength.

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Topic 18: Shape memory alloys and their usage in space technologies

Roll No:

190111 190374 190876 190110

Shape memory alloys (SMA) are metals having two very unique properties, i.e.,

pseudoelasticity and shape memory effect. SMA are deformed after cooling them below

transition temperature. These deformed SMA return to their original shape upon subsequent

heating. This can be seen in the figure below.

Courtesy: https://webdocs.cs.ualberta.ca/~database/MEMS/sma_mems/sma.html

Please refer to the link for applications of SMA in space engineering:

https://www.researchgate.net/publication/228504809_Applications_of_shape_memory_alloy

s_in_space_engineering_past_and_future

For your assignment, you are required to discuss the stress and strain that are related to such

transformations. Also, envisage can we use them in space. Where? Which application? How?

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Topic 19: Design of painless needle injection

Roll No:

190097 190392 190240 190303

Needle injections have always been painful. Inspired from the mosquitos inserting their needles

and extracting our blood without us even noticing, researchers have developed painless

needles. This mosquito inspired painless needle is a microneedle composed of ductile

polymeric material.

As can be seen in figure below, these needles have an altogether different structure. For your

assignment, discuss how this structure is helpful in reducing the pain experienced using stress-

strain analysis.

Courtesy - https://www.biocompare.com/Life-Science-News/351335-Mosquitoes-Are-Inspiration-for-

Development-of-Painless-Microneedles/

For more reference, you can follow the following articles:

https://iopscience.iop.org/article/10.1088/1748-3182/3/4/046001/meta

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/6799/67990Q/Design-of-

painless-microneedle-for-blood-extraction-system/10.1117/12.759058.short?SSO=1