PART – I

(i) Cylindrical shaped pressure vessel with both ends opened

• Translation of problem indicating function, objective, constraints and free variables?

(3 marks)

• Derive the performance material index for failure.

## (7 marks)

(c) Discuss the implication of two performance index i.e., due to yielding and fast fracture for the selection of one material. Find the coupling line by making equal the cost calculated with the two indexes.

## (4 marks)

(d) Use CES EDUPack (Rebranded as GRANTA EDUPACK 2020) to create a graph representing the material index and identify the region of the chart with the cheapest materials for the pressure vessel due to yielding and fast fracture material index.

[Hint 1]: Use the concept of coupling line for selecting best material materials for the cylindrical pressure vessel due to yielding and fast fracture material index.

(6 marks)

PART – II

## (ii) Spherical shaped pressure vessel

(e) Translation of problem indicating function, objective, constraints and free variables?

(3 marks)  (f) Derive the performance material index for failure.

## (7 marks)

(g) Use CES Edupack (Rebranded as GRANTA EDUPACK 2020) to create a graph representing the material index and identify the region of the chart with the cheapest materials for the for the pressure vessel due to fast fracture material index.

## (5 marks)

Reminder, as it is an open exercise, each student is expected to have a unique solution as definition of the problem will be unique.

(Total: 35 marks)

QUESTION 2

## PART – I

A truck manufacturing company wants to design a new material for the springs used in the heavy loaded trucks (Figure Q 2). In vehicle suspension design it is desirable to minimize the mass of all components and select a material as cheap as possible. You have been asked to select a material and dimensions for a light spring to replace the steel leaf-spring of an existing truck suspension. You need to decide the structure of the existing leaf-spring. The new spring must have the same length, L and stiffness, S as the existing one, and must deflect through a maximum safe displacement, δmax without failure.

### Figure Q – 3 : Vehicle suspension system

You will need to decide extra constraints and find out the necessary equations to solve the springs for truck application. You will need to decide your objective and to compare the results with real world materials. You will need to translate the problem, derive the performance index or indexes, coupling line between the performance index and select some screening constraint.

[Hint 1]: You will have to decide your own dimensions for the selected structure and the constraints.

You have to document the whole selection process.

• Definition of the problem
• marks)
• Translation of the problem
• marks)
• Derive performance index

(8 marks)

• Use CES Edupack (Rebranded as GRANTA EDUPACK 2020) to create a graph representing the material index and identify the region of the chart with the cheapest materials for the leaf spring.

(6 marks)

## PART – II

Most of the springs are made of high strength alloy steel, and they are heavy. You are asked to explore the potential of alternative materials for lighter springs, recognizing there must be a trade-off between mass and cost if it is too expensive, the manufacturing company will not want it even if it is lighter.

Show that the mass and material cost of the spring relative to one made of high strength alloy steel is given by

= ( ) ( , ) and = ( )( , , )

where ρ is the density, σf the failure strength and Cm the cost per kg of the material, and the subscript “o” indicates values for high strength alloy steel.

[Hint 2]: Use the ratio for new material over the steel.

= ℎ ℎ ℎ

0

and   = ℎ ℎ ℎ 0

• Show that the mass and material cost of the spring relative to one made of high strength alloy steel is given by

= ( ) ( , ) and = ( )( , , )

(2 marks)

• Explore the trade-off between relative cost and relative mass. Sketch a trade-off surface. Define a relative penalty function.

(6 marks)

Reminder, as it is an open exercise, each student is expected to have a unique solution as definition of the problem will be unique.

(Total: 30 marks)

## QUESTION 3

• Draw the Time Temperature Transformation T-T-T diagram for Aluminium – Copper

(Al – 4 % Cu) alloys and show on the diagram the critical cooling curve, the transformation lines, the phases and the axis.

(4 marks)

• Explain the change of structure with martensitic transformation of steels.

## (2 marks)

(c) The copper-tin system (which includes bronzes) is shown in the Figure Q – 3 below

### Figure Q – 3: Copper – Tin phase diagram

Note: Use the Annexure 1 for calculations

• List and mark out the single phase regions;

(2 marks)

• Highlight the four eutectoids in the copper-tin system,

## (2 marks)

• List out the compositions and temperatures of the eutectoids.

(4 marks)

• Discuss with help of simple sketch along with an example of the phase diagram (binary system) in which PERITECTIC REACTION AND PERITECTIC

POINT, reaction occur during the phase transformation of metals. Describe the phase reaction and the corresponding temperature for the selected example.

(2 marks)

(Total for part (c) : 10 marks)

(d) Compare and contrast the main features of diffusive and displacive transformations during structural changes in metals.

(4 marks)

(Total: 20 marks)

## QUESTION 4

Houses in UK uses cast iron or steel guttering and this gutter material is prone to corrosion over time as shown in Figure Q – 4.

• To prevent the mild sheet-steel guttering from corrosion it is copper-plated and the guttering acts as a drain for sea water. If the coating is damaged, exposing the steel, will the guttering corrode in a damaging way?
• If instead the guttering is zinc-plated, will it be better or less well protected?

Suggest the mechanism of corrosion taking place in these two types of coating on the mild sheet-steel guttering.

Figure Q 4: Corrosion of steel gutter

(Total: 5 marks)

## QUESTION 5

• Using suitable examples, explain the meaning of dislocation movement in metals. Explain with simple sketches different types of dislocation in relation to metals.
• marks)
• Using suitable industrial examples, explain creep in metals. Comment and contract dislocation movement in both plastic deformation and in creep.

## Mechanical Engineering homework help

63 questions

Automotive assignment
Thanks

## Mechanical Engineering homework help

63 questions

Automotive assignment
Thanks

## Mechanical Engineering homework help

63 questions

Automotive assignment
Thanks

## Mechanical Engineering homework help

This is material and science engineering and I want someone who knows this course very well,

## Mechanical Engineering homework help

Watch the following video produced by PBS and NOVA with the Materials Research Society (MRS): Making Stuff Stronger:  https://vimeo.com/286473392

1- A short description, commenting on current technology as well as the future prospects of the materials discussed

2-  Pick one of the material systems discussed in the above video and describe its basic properties, production, characterization, applications and references cited (you need to reference your work)

## Mechanical Engineering homework help

This is the project. But I am looking for calculation only. I have attached the data and the description. My Project data is of Underground Loader. So please take the data of Underground Loader value from the Table attached

## Mechanical Engineering homework help

The project is a video presentation of a PowerPoint. I will need notes in the PowerPoint to read will recording.

please make a professional PowerPoint with notes embedded so i can record the video presentation

Thermodynamic properties of propane and refrigerant 134a & Propane p-h diagram & Refrigerant R134a p-h diagram I attached this please check

Additional hints on solving the project problem

27 Nov 2020

Mathematical background

1) You can use the first law analysis of open systems in order to write down the equations for net power generation in the combined cycle and efficiency. It will be a set of simple equations with many unknown parameters. (i.e. the enthalpies of many states, e.g. 8-11, the mass flow rates, etc.)

2) You will notice immediately that you have many more unknown variables than known or given parameters. You will need to formulate a system of equations to solve the problem. For a well constrained/defined system, you will end up with the same number of equations and unknown variables. Some of these equations you can write explicitly (like using the first law of thermodynamics in an open system to link power, mass flow rates, and enthalpy differences). Other properties are linked by fluid-specific equations, which may be tabulated (like an equation of state that links the pressure, density, and temperature of a fluid).

3) Eventually, you will find that you need to know four additional parameters in order to close the system (i.e. have a number of unknowns equal to the number of equations). These four parameters in this project are given to be P2/P1 , T8 , P8 , and P9. This is a selection that was made for you, so that the problem be more tractable. After this point, you will need to guess values of these four parameters (P2/P1, T8 , P8 , and P9) in order to solve the cycle. Different choices for these parameters will lead to different solutions for the cycle. In principle, some choice of these parameters would lead to maximum values for power and efficiency, but finding that choice is not trivial (it involves an iterative process, that is frequently used in engineering). But remember, in all cases, all your parameters would have to satisfy the equations that apply for the problem.

4) For the purposes of this project, you might just try a few iterations to observe trends (even if you have to solve the calculations by hand, i.e. determine enthalpies and other properties from the applicable tables) rather than exhaustively finding the optimal parameters, using CoolProp that can determine the properties in an automated fashion. In engineering, one is better served by keeping all parameters fixed and changing another parameter, to designate how the main outcome variable is affected. For example, does a higher value of T8 when P2/P1 , P8 and P9 are fixed, increase or decrease the efficiency of the cycle? This method would guide you towards improving efficiency as you modify the assumed value of each of the four parameters.

Practical example of the solution procedure:

Identify the properties necessary for efficiency and power, as above. The system of equations between the given properties, guessed properties, and efficiency and power will have to be solved one time, after which time you can just plug in different values for the guesses. Here are the details for one iteration for R-134a. (I pulled the numbers from CoolProp, your values for enthalpy will be different if you use the tables from the back of your textbook, but the differences in enthalpies should be very close)

1) Guess the four parameters identified from the start: a) P2/P1 = 10, b) T8 = 450 K, c) P8 = 20 bar, d) P9 = 12 bar.

2) From the given/guessed properties and constant pressure processes, you can solve for the pressures everywhere P2, P3, P4, etc.

3) Calculate isentropic state 2s, i.e. T2s

4) Calculate state 2 accounting for isentropic efficiency of compressor. (in this case, T2 = 629K)

5) Calculate isentropic state 5s

6) Calculate state 5 accounting for the isentropic efficiency of the turbine (in this case, T5 = 708K)

7) Calculate state 3 using regenerator equation. (I got T3 = 692 K)

8) Calculate state 6 using the energy balance on the regenerator.

9) Identify mass flow rate of the air in the gas turbine part of the cycle by comparing net power and the information from the turbine and compressor. (I got 0.65 kg/s)

10) Specific enthalpy and entropy of the R-134a state going into the turbine of the Rankine cycle can be obtained from your guess. You need to make sure it is a vapor state…

11) Calculate the isentropic state 9 using your guessed P9 and the fact that s8 = s9s

12) Use the isentropic efficiency of the turbine to calculate the real state 9 (I got T9 = 432 K)

13) Identify the density of the saturated liquid leaving the condenser. You can use this along with the pressure difference to calculate the isentropic power of the pump.

14) Use the isentropic efficiency of the pump to calculate the real power of the pump.

15) Use the energy balance on the heat exchanger in order to calculate the mass flow throughout the Rankine cycle. (I got 0.39 kg/s)

16) The above steps should result in values for all the parameters you need in order to calculate total thermal efficiency and total power. (I got 102.1 kW, and an efficiency of 31%)

17) Evaluate the feasibility of the result. Does the system violate the second law of thermodynamics anywhere? Are the values of temperature and pressure at different states appropriate?

18) Change parameters (sensibly) and repeat the above steps to determine whether you could find another set of the four parameters that produce a higher efficiency and/or maximum net power.

## Mechanical Engineering homework help

Use the Ashby Diagrams to compare relative IMPORTANT properties (the properties identified in 3b for a ferrous and non-ferrous metal, polymer, ceramic and composite).  Include these Ashby Diagrams and mark an X to show the comparisons.  Write a reflection about the type of material that best meets each property.  So for example. For the Occluder ball, two of the five properties determined to be relevant to a design constraint were density and fracture toughness.  As such, I will include the Ashby diagram for these two properties.  STOP!! MANDATORY CONSULTATION TIME WITH MARGIE!

Source of image (http://www.lehigh.edu/~intribos/resources.html).  I would then comment on the relative properties of these materials.  For example – The Composite materials offer nearly equal fracture toughness while also providing for low density (light weight)…etc.

## Mechanical Engineering homework help

Need help to prepare the attached project professionally before the due date.

mechanical engineering filed.

## Topics Covered:

1.  Combustion process in the Spark-Ignition Engine.

3. Combustion Process and Thermal Efficiency of Diesel Engines

4. Vapor Absorption Refrigeration System by Solar Energy

MEC352 –Thermodynamics II

Fall 2020

Group Design Project (4 members)

Due 5:00 p.m., 13/12/2020

# Topics Covered:

### 1. Combustion Process in the Spark-Ignition Engine

1. Vapor Compression Refrigeration System
2. Combustion Process and Thermal Efficiency of Diesel Engines
3. Vapor Absorption Refrigeration System by Solar Energy

# Write-up:

Your report should have the following sections:

Introduction, theoretical analysis, design, results and discussion, and summary

Include the following in your write-up:

• Develop a detailed thermal model.
• Justify all equations and
• Discuss why this general design was
• Discuss design specifics and
• Show why your design is
• Cite with reputable sources (i.e. not Wikipedia, ).
• Include any code used for the analysis in the appendices, such as Excel, Matlab,
• Include detailed drawings for accurate reproduction of your thermodynamics analysis.

Grading note: Group participation will be taken