Write one well-formed paragraph that summarizes the design process described in the case study.

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Medical Device Innovation and Entrepreneurship

Case Study 1

Read the case study in the attached CS file, and take note of the different processes mentioned that were discussed in class. After reading, submit answer to the following questions in Blackboard.

1. Write one well–formed paragraph that summarizes the design process described in the case study. To get full credit, your well–formed paragraph must be at least 4 sentences, include a thesis statement that summarizes the paragraph, and have supporting sentences that give evidence for your statement.

The cash flows associated with a public works project in Buffalo, New York, are shown. Use the modified B/C ratio at a discount rate of 5% per year to determine the economic justification.

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CEIE 301 – Engineering and Economic models in civil engineering

7.7 The cost of grading and spreading gravel on a curvy rural road is expected to be $300,000. The road will have to be maintained at a cost of $25,000 per year. Even though the new road is not very smooth, it allows access to an area that previously could only be reached with off-road vehicles. The improved accessibility has led to a 150% increase in the property values along the road. If the previous market value of the property was $900,000, calculate the conventional B/C ratio using an interest rate of 6% per year and a 20-year study period. (5 points)

7.13 A government-funded wind-based electric power generation company in the southern part of the country has developed the following estimates (in $1000) for a new turbine farm. The MARR is 10% per year and the project life is 25 years. Calculate the (a) conventional B/C ratio, (b) modified B/C ratio, and (c) PI value. Benefits: $45,000 in year 0; $30,000 in year 5 Government savings:

  • $2,000 in years 1 through 20
  • Cost: $50,000 in year 0
  • Disbenefits: $3000 in years 1 through 10

(5 points)

7.16 The cash flows associated with a public works project in Buffalo, New York, are shown. Use the modified B/C ratio at a discount rate of 5% per year to determine the economic justification.

  • First cost, $ 50,000,000
  • AW of benefits, $/year 7,500,000
  • AW of disbenefits, $/year 1,700,000
  • M&O costs, $/year 900,000
  • Life of project, years 30

(5 points)

7.26 The two alternatives shown are under consideration for improving security at a county jail in Travis County, New York. Determine which one, if either, should be selected based on a B/C analysis, an interest rate of 7% per year, and a 10-year study period.

  • Extra Cameras
  • (EC)
  • New Sensors
  • (NS)
  • First cost, $ 38,000 87,000
  • Annual M&O, $ per year 49,000 84,000
  • Benefits, $ per year 110,000 87,000
  • Disbenefits, $ per year 16,000 —

(10 points)

7.29 A group of engineers responsible for developing advanced missile detection and tracking technologies such as shortwave infrared, thermal infrared detection, target tracking radar, etc. recently came up with six proposals for consideration. The present worth (in $ billions) of the capital requirements and benefits are shown. Determine which one(s) should be undertaken, if they are (a) independent and (b) Alternative A B C D E F

  • PW of Capital, $ 80 50 72 43 89 81
  • PW of Benefits, $ 70 55 76 52 85 84

(10 points)

Determine the combined critical speed of shaft in HW 06 problem 1 using Dunkerley’s equation. Assume uniform diameter of 1.3in throughout.

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MEE 342 – Principles of Mechanical Design

1. Determine the combined critical speed of shaft in HW 06 problem 1 using Dunkerley’s equation. Assume uniform diameter of 1.3in throughout.
2. Determine the combined critical speed of shaft in HW 06 problem 2 using Dunkerley’s equation. Assume constant diameter throughout. If the operating speed is unsafe, suggest alternate solutions.
3. The shaft in HW6 problem 2 is used for shaft b in 11W4 problem 3. Design bearings at supports such that each bearing will last 5 kilohours at 2000rpm and have a minimum reliability of 0.99.

Create a code to solve the following problem in EES. Use property calls to get enthalpies or other data that would usually be looked up in the tables.

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Engineering Equation Solver (EES) code to solve problem

1. Create a code to solve the following problem in EES. Use property calls to get enthalpies or other data that would usually be looked up in the tables.
Problem Statement: A simple ideal Rankine cycle with water as the working fluid operates between the pressure limits of 15 MPa in the boiler and 100 kPa in the condenser. Saturated steam enters the turbine.

Find:

  • a) The work produced by the turbine.
  • b) The heat transferred in the condenser.
  • c) The work consumed by the pump.
  • d) The heat transferred in the boiler.
  • e) The thermal efficiency of the cycle.
  • f) The back-work ratio

2. Create a parametric table by changing the pressure across the boiler from 20 MPa to 1 MPa. (There will be 20 runs)

a. In the table should be the six values that you found above.

b. As a comment in the code, analyze the table. Below are some questions to think about.

  • i. What trends do you see?
  • ii. Why do you think those are happening?

3. Plot the cycle on a T-s diagram

  • a. Using a look-up table plot the points on the
  • b. As a comment in the code, describe what you see in the plot. Does it match the Ideal Rankine cycle we talked about in class?

Make sure EES is set to the correct unit system for the problem. Recommended approach:

  1. Create variables for all your given information.
  2. Write the governing equations to solve the processes in EES.
  3. Identify what is unknown and create property calls or additional equations to get that information.

Create a load displacement curve for the pile, either by applying incremental displacement up to 0.1D or by applying incremental loading (e.g. every 1 Qu) for an purely elastic analysis, and compare with the results of the elastic solution by Randolph and Wroth.

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Computational Geotechnics; Elastic and Elastic-plastic deformation of piles and pile groups

Marking scheme:

  • Research & referencing (15%)
  • Analysis (25%)
  • Computer modelling (25%)
  • Results & discussion (25%)
  • Presentation (10%)

 

Coursework brief:

Model 1) You are asked to analyse the pile shown in Figure 1, for the parameters shown in Table q, according to the last digit of your student ID. Steps to follow:

  • Calculate the bearing capacity of the pile, using an undrained analysis. For the interface parameters, use any relevant source from the
  • Model the pile using an axisymmetric model in Plaxis 2D and
    1. Create a load displacement curve for the pile, either by applying incremental displacement up to 0.1D or by applying incremental loading (e.g. every 1 Qu) for an purely elastic analysis, and compare with the results of the elastic solution by Randolph and Wroth.
    2. Compare the previous 2 curves with the load displacement curve for the pile, for an elastic-plastic MC analysis and compare the bearing capacity
  • Apply a safe design load on your pile (FS=3) and get the axial load, displacement and interface shear force distributions along the pile, compare with the elastic solution by Randolph and Wroth

For your model, it would be easier to consider the pile weightless, otherwise you will have to subtract the pile weight from the calculation. Comment of the advantages and the implications of that.

Model 2) Your pile above, is now a part of a 3-by-3 pile group, at a spacing s/d given in Table 1. Steps to follow:

  • Calculate the theoretical efficiency ratio and the bearing capacity of the pile group, as well as the settlement and the distribution of the axial loads of the piles for the safe load on the group (FS=3).
  • Create a plane strain elastic model using an “Embedded Beam Row” element for your piles and a plate element for the pile cap, as shown in Figure 2 and
    1. First de-activate the pile cap and try to get an idea of the pile stiffnesses and interaction factors from Plaxis, by applying loads on piles independently, following an elastic
    2. Activate the pile cap and apply the safe load on the pile group and compare the settlement and axial forces on the piles, with your theoretical
  • Add some moment increments, no greater than the one which can cause an axial bearing capacity failure to a pile of the group and compare the rotational stiffness and rotation with your theoretical Also try to identify how the interaction affects the displacements of the extreme piles of the group.

Again, for your convenience, assume piles and pile caps weightless, but comment on the benefits and drawbacks of doing that.

 

Table 1. Modelling parameters

Last digit of student ID L

 

m

 D

 

m

 Cu1

 

kPa

 L2

 

m

 Cu2 kPa s/d
0 16 1 60 6 200 3
1 18 0.8 140 8 400 4
2 20 0.5 100 7 300 5
3 22 0.6 80 10 250 6
4 25 0.8 250 5 600 7
5 15 1.2 40 6 500 8
6 17 0.6 70 5 150 9
7 21 0.7 200 7 450 10
8 23 0.8 80 8 320 6
9 24 1 50 10 180 5

 

Figure 1. Single pile to be analysed with an axisymmetric model

M

 

 

Figure 2. Pile group to be analysed with a plane strain model

What do you think about the court’s decision to affirm the Board’s ruling to revoke all three certificates? In light of this case, and similar cases mentioned in the chapter, what are the benefits and drawbacks of the current licensing system.

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Chapter 8 Discussion: Duncan v. Missouri Board

Read the case beginning on page 140 and answer the prompt below in 1-2 paragraphs.

What do you think about the court’s decision to affirm the Board’s ruling to revoke all three certificates? In light of this case, and similar cases mentioned in the chapter, what are the benefits and drawbacks of the current licensing system.

*Do not forget to click “reply” so that the discussion is in one thread.

Respond to at least one other colleague.

Textbook Link http://library.lol/main/A272E9AAB5A42F55A478B5487E…

Write feedback one page about “Recently Power Transformer Testing, Monitoring, Maintains and Protection in USA”.

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Engineering Question

Write feedback one page about “Recently Power Transformer Testing, Monitoring, Maintains and Protection in USA”.

  • Expected Layout:
    • Font: 11-pt Time New Roman with 1.25 line spacing
    • Page layout: 1″ margins / Normal

    for the source you have only ONE OPTION

  • you can use any information, source from the internet relative to this guy “Robert Carritte” talk about the Power Transformer Testing, Monitoring, Maintains and Protection to write a feedback.
  • Don’t use another person or other sources to write

What are the principles behind Value Engineering Change Proposal (VECP)? What is the distinction between design specifications and performance specifications?

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Civil Engineering Question

Answer the questions below based on the information in chapter 14:

1) What are the principles behind Value Engineering Change Proposal (VECP)?

2) What is the distinction between design specifications and performance specifications?

3) When it comes to authority, why is it important to have clear lines of specific authority on a particular project

4) Discuss the strengths and weaknesses of at least three project delivery systems.

 

Textbook Link http://library.lol/main/A272E9AAB5A42F55A478B5487E…

develop a Request for Professional Engineering Services as an owner/operator of the project proposal.

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Establishing a procurement

Focus  on the Proposal Requirements of the building a five story office complex project and need a 2 page paper on the Proposal Requirements, which include the

  • Cost
  • Qualifications/Experience Desired
  • Delivery

The purpose of this project, is to develop a Request for Professional Engineering Services as an owner/operator of the project proposal. In this effort, your team will procure engineering services related to a project from one of the following possible work assignments in the civil engineering field.

Calculate the alternating stress amplitude (equal to the maximum normal stress) for each load, and plot this on a graph as a function of logl0 number of cycles N. (Should be a semi-log plot.)

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Fatigue Testing

EXPERIMENT # 4

Safety first!

  1. Proper protective eyewear must be worn while operating the fatigue tester.
  2. Place the guard shield in place before starting a fatigue test.
  3. Never touch the sample while it is rotating.
  4. Caution: the sample may be hot after the test.

 

Objectives

  1. To determine how surface finish affects fatigue life.
  2. To determine how fillet radius affects fatigue life.
  3. To observe fatigue fracture surface markings and be able to differentiate fatigue from fast fracture markings.
  4. To generate a Wöhler diagram (an S-N curve) and extract information relating to fatigue limit, fatigue strength, and fatigue life.

Background

Material fatigue is a well-known situation whereby rupture can be caused by a large number of stress variations at a point, even though the maximum stress in the material is less than its yield stress. As the number of load cycles increases, the permissible stress level declines. Fracture is initiated by tensile stress at a flaw in the material (the flaw may be microscopic or macroscopic). Once started, the edge of the crack acts as a stress raiser and assists in propagation of the crack until the reduced section can no longer carry the applied load, and the part fails.

While it appears that fatigue failure may occur in all materials, there are differences in the incidence of fatigue. For example, mild steel is known to have an ‘endurance limit stress’ below which fatigue fracture does not occur, no matter how many loads cycles the material experiences, which is known as the fatigue limit. With non-ferrous materials, such as aluminum alloys, however, there is no such limit. As a consequence of these differences, there are two design methods. With a material like mild steel, the stress range can be kept below the endurance limit to ensure failure will not occur. Alternatively, one can design for a specified number of stress variations, on condition that the part will be replaced at that stage. The latter method is quite common with aircraft where the use of aluminum is widespread.

Fatigue strength is also significant in machine design. When designing a part for fatigue strength, an engineer uses results from a fatigue test. However, when designing for infinite life (millions of cycles), such results may not exist and will take too long to determine. In such a case, interpolation from the measured fatigue data will be used instead. To introduce this very complex subject in a simple way, the apparatus demonstrates the classical fatigue experiments carried out by Wöhler. He selected the method of reversing the stress on a part by employing a cantilever beam rotated about its longitudinal axis, therefore the stress at any point on the surface of the beam varies sinusoidally. A Wöhler diagram (stress-number (S-N) curve) can be created by repeating the experiment at many different loads and recording the number of cycles until failure occurs.

 

Fatigue Testing Machine

The Gunt Fatigue Testing Machine provides a simple way of observing the effect of fillet radius and surface smoothness on a material subjected to fluctuating flexural stresses. The fatigue tester is driven by an induction motor, which is connected on one side to a counter mechanism. The tapered test piece is attached to a very stable shaft in between two spherical ball bearings. The loading fixture is attached to the shaft at the other end. The loading device consists of a spherical ball bearing and a micro switch that automatically switches off the motor when the fracture occurs. The loading on the test piece can be increased by turning the loading wheel clockwise. The force applied to the test piece by a spring can be varied from 0-300 N. A load cell measures the applied force. The number of load changes and the applied force are read directly from the LCD.

 

Basic Principles

In the fatigue apparatus, the specimen acts as a clamped beam (left end) under a concentrated force F (right end). This induces a triangular bending moment along the length of the specimen, with a maximum bending moment of . As shown in the figure, a is the length of the specimen. The bending moment is largest at the clamped end and drops to zero at the free end. We expect the specimen to fail where the loading is highest, i.e., at the clamped end.

Under pure bending, the normal stress varies in the cross-section as well, going from zero at the neutral axis (the center of a circular cross-section) to a maximum/minimum value at the outermost surface of the specimen. One side of the beam is in tension while the other is in compression. The maximum normal stress in a beam, s, is:

Where Mb is the applied moment, c is the distance from the centroid to the outermost surface (in this case, r), and I is the moment of inertia about the centroid, which for a circular cross-section, is:

The cyclic stress experienced by a specimen during a fatigue test is composed of a constant part, the mean stress, which is caused by an initial load, and a superimposed cyclic part with an alternating stress amplitude. In this experiment, the bending moment is fixed and the specimen is rotating, which results in an alternating, sine-shaped bending stress, with a mean value () of zero. The alternating stress amplitude in the specimen is a function of the applied bending moment (described above), and the geometry (described below).

In this experiment, the alternating stress amplitude, , is equivalent to the maximum normal stress in the beam. Combining all equations, the alternating stress amplitude is given by:

 

Test Procedure

You will run the fatigue experiment on three different specimens of heat-treated steel, details of which are shown in the table below:

 

Specimen Fillet radius (mm) Surface roughness Rt (μm) Notes
1 0.5 4 Sharp corner, smooth
2 2 4 Curved corner, smooth
3 2 25 Curved corner, rough

 

As the time required for a fatigue experiment is prohibitively long for small loads, all three specimens will be loaded with a relatively high force of 200 N in this lab.

  1. Measure the diameter of the specimen and inspect the surface roughness.
  2. Insert the specimen into the equipment.
  3. Measure the distance from the neck to the specimen’s contact surface with the bearing.
  4. Refer to the PDF “Fatigue Testing User Manual – For Students” for specific instructions on setting up and running the experiment.
  5. Once the experiment is complete, record the number of load cycles to failure (N) and calculate the maximum normal stress in the specimen.

 

It takes much longer to create a complete S-N curve given the nonlinear nature of the response. Data were taken on five #3 specimens, and the results are shown in the table below:

Number Load (N) Stress (N/mm2) Cycles to failure, N Duration (min)
1 200   14030 5
2 170   48800 17
3 150   167000 60
4 130   455000 162
5 120   1280800 457

For these specimens, the length was a=100.5 mm, and the diameter d=8 mm

  1. Calculate the alternating stress amplitude (equal to the maximum normal stress) for each load, and plot this on a graph as a function of logl0 number of cycles N. (Should be a semi-log plot.)

 

Report

A full lab report is to be submitted. The lab report should include the following:

  1. Explanations of the fatigue limit, fatigue strength, and fatigue life.
  2. Maximum normal stress calculation for each load.
  3. Discussion about the fractured surface cross-section and identification of the cause of the rupture.
  4. How was the lifespan affected by fillet radius? Compare specimens #1 and #2.
  5. How was the lifespan affected by the surface smoothness? Compare specimens #2 and #3.
  6. An S-N curve (Wöhler diagram) for the experimental data provided for specimen #3.