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  1. mattyboson12

    Control systems -- input with non-zero initial conditions

    1. Homework Statement Deriving an s-domain equation for the following inputs a) &b) 3. The Attempt at a Solution I understand how to derive the equation for an input with zero initial conditions (part a) but I'm not sure what to do when there are non-zero initial conditions (part b)
  2. mattyboson12

    Composite lay-up

    1. Homework Statement a)Describe a potential laminate lay-up that would exhibit high shear stiffness b)Describe a potential laminate lay-up that would exhibit a low poissons ratio 3. The Attempt at a Solution a) is a unidirectional lay-up in the direction of the shear force best? b) an evenly...
  3. mattyboson12

    Radial/Hoop stress in a steel turbine disc

    1. Homework Statement 2. Homework Equations -given in question 3. The Attempt at a Solution I am bit confused with the boundary conditions of this problem. I understand the radial stress is zero on the inside diameter and the radial stress on the outside diameter will be the reaction to...
  4. mattyboson12

    Material selection for vehicle leaf spring

    1. Homework Statement I've gone though a material selection process to pick the optimum material for a rear leaf spring suspension for a vehicle (~700mm long) and I've selected the top 10 materials based on fatigue, fracture, toughness, cost, yield etc: -Stainless steel, martensitic, AISI...
  5. mattyboson12

    Material selection based on either U1 or U2 merit index

    1. Homework Statement Choose a component based on either U1 or U2 merit index and select what you believe to be the optimum material. 2. Homework Equations U1=(σ)^2/E (Energy density) U2=(σ)^2/(Eρ) (specific energy density) 3. The Attempt at a Solution I was going to use a spring damper...
  6. mattyboson12

    Von Mises stress

    Thank you
  7. mattyboson12

    Von Mises stress

    If the von mises stress well is below the yield stress, am I right to assure the material is behaving elastically?
  8. mattyboson12

    Picking an element type for FEA

    When choosing between a 2D 4-node quadrilateral element and 8-node for FEA stress analysis, why is the 8 node option preferred? I understand it has much more flexibility with different shapes due to the central mid node but are there any other reasons?
  9. mattyboson12

    Proximity Sensor, Design Project

    I've taken a year out of university to work at a design company and they have given me a project to design/make a test rig which measures the position of a metal shaft within an actuator assembly to check if its within a +/- 0.2mm tolerance. Some of the key requirements are: No contact with...
  10. mattyboson12

    Thermal Resistance

    1. Homework Statement Explain how the concept of thermal resistance can be used in the analysis of heat transfer problems 2. The attempt at a solution So I'm made a few key points but I am not sure if I have answered the question fully: Thermal resistance is a heat property and a...
  11. mattyboson12

    Surface temperature of a tile

    I've double checked my code and all the methods seem to be okay. Yep, i have used the tri-diagonal matirx and then the built in function tdm() to solve the matrix Matt
  12. mattyboson12

    Surface temperature of a tile

    Hi Chet The program calculates the temperature using fourier's equation in one dimension: dU/dt=α*(d^2 U/d^2 x) . I'm guessing crank is the best method as it seems to have the best compromise between stability/accuracy compared to the others. I am just confused as to why the differencing...
  13. mattyboson12

    Surface temperature of a tile

    Hi, I have written a matlab program to calculate the surface temperature on a tile and I am trying to find the most stable/accurate differenceing technique. I have plotted the surface temperature (where its actual value is ~122.5) against the time step for the differencing techniques shown...
  14. mattyboson12

    Flat-pack coffee cup

    Hi, I am a 2nd year student studying Mechanical Engineering. As part of our design module we are doing a feasibility analysis into a 'disposable Fold-flat cup with an integrated lid' which is to replace existing coffee cups. I understand their are some patents for similar products which would...
  15. mattyboson12

    Heat transfer across an infinite plate of constant thickness

    I read the following in a text book: "The temperature in the tile is to be analysed by solving Fourier's equation numerically using a finite difference technique. To simplify the problem, the following two assumptions are made: It is modelled as a one-dimensional problem. Only heat flow across...
  16. mattyboson12

    Heat transfer across an infinite plate of constant thickness

    When modelling the heat transfer through a plate using fouriers equation, what difference would it make if the width and length of the plate were set to a specified value rather than being infinite?
  17. mattyboson12

    Heat transfer radiation

    1. Homework Statement A circular floor 9.15 m in diameter has an emissivity of 0.8 and is at a temperature of 29.4C. The floor is enclosed by a hemispherical metal dome which has an emissivity of 0.1. If the net rate of heat transfer between the floor and the dome is 660 W, calculate the...
  18. mattyboson12

    MATLAB MATLAB, NASAs thermal protection system

    Hi, I am writing program to model the heat flow through different space shuttle tiles. I have got it working using four different methods: Forward differencing, Backward differencing, Crank-Nicolson, DuFort-Frankel and all four methods give me similar results. What are the advantages and...
  19. mattyboson12

    Space shuttle thermal protection tiles

    Hi, I am writing a MATLAB program to model the heat flow through space shuttle tiles. Does anyone know where I can find the thermal conductivity, density and specific heat of the different tiles on a space shuttle?
  20. mattyboson12

    Steam Motor Efficiency

    I am doing an experiment to determine the performance of a steam plant cycle and analyse it in comparison with the ideal rankine cycle. I have a sketch of the actual and real T-S diagram for the steam plant (See attached) I am unsure what factors cause the change in the shape of the T-S...
  21. mattyboson12

    Secondary phase, heat treatment

    "Precipitation hardening is a heat treatment that distributes secondary phases more evenly in an alloy..." What does it mean by a secondary phase?
  22. mattyboson12

    PLEASE HELP. Gyroscope question

    [Question] Homework Statement [/b] A special purpose fan is mounted as shown in figure Q5 (Ive attached a picture of the diagram). The motor, armature, shaft and blades have a combined mass of 2.2Kg with a radius of gyration of 60mm. The axial position of b of the 0.8kg block A can be slid on...
  23. mattyboson12

    Pressure Vessel Question

    A spherical pressure vessel of internal diameter 2m is constructed by bolting together two hemispherical domes with flanges. Assuming that the number of bolts used to join the two hemispheres together is 12, determine the wall thickness of the dome and the diameter of the bolts, if the maximum...
  24. mattyboson12

    Fluid Dynamics Question

    Thank you for the reply. This is my answer but I'm not sure if its right as I am getting a negative value for the pump power?
  25. mattyboson12

    Fluid Dynamics Question

    Hi, am having a few problems applying bernoulli's equation when an electric pump is involved. I have attached a picture of the question. I understand how to apply bernoullis for venturi and pitot tubes but when it involves work being done on the system eg. a water pump, fan exhaust I dont know...