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Mechanical Engineering


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  • Engineering Qualification
    Bsc Mechanical Eng
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    University of Nairobi

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  1. Hi Jake, This is abit late. Hope it will be of assistance.
  2. Hi Govardhanan, Allow me to answer equally simply. 1. I can see the setup has two main phases; the motor, rack and pinion phase, and the piston food in a cylinder phase. 2. To size the motor you need to determine the load required to desirably dispense the food. This can be achieved through determining the required load at the piston. The exercise may be approached in varied ways including; using physical loads on piston. 3. Upon determining the required load range, work it backward to size the motor. Remember energy input at motor rack phase = energy output at piston * efficiencies(may start with 80%). Best of lack
  3. Hi Pablo, Have to deal with case by case of each shaft diameter, General rule is use the Yield strength as it defines the onset of plastic deformation. Two, work with the outer most diameter as for any shaft plasticity start at the outer most layer of the shaft. Therefore if the shear stress of outer most layer of the shaft is below the yield shear strength, then your shaft is safe. (Assumption; we are dealing with torque loads). Regards. Michael Given the tensile strength is important to get the appropriate shear strength for your analysis. Different materials have differing relations between tensile and shear stress.
  4. Hi, Yes they are experimental averages and their publication means that they are considered to be good working values. Allow me to add that source for the values is also important. Is the source authentic. If so, you are good to go. Regards.
  5. Hi Hari Your question is not so clear what want however allow me to make an attempt this ways: 1. If you are determining the gear module from the gear parameters that have been given to you then, use the standard gear equations available in gear literature. 2. If you are a designer and have identified your independent gear variable, say input parameters, then you select a gear module that would best fit the desired output performance of the gear system. This will be achieved using a combination of calculation approaches, including; step 1 above, iteration to best fit output performance, iteration to fit permissible input and out put parameters (where compromises are required). In this case sizing to fit available space and weight becomes an issue. After this long process you will have determined your most befitting module for your gear system. Hope this breaks the ice. Regards. Michael
  6. Hi Bob, First speech of my entry undergraduate Professor cautioned me that am not taking the Mechanical Engineering Undergraduate degree for the sake of the subject contained, but for purposes of enabling me to look at things in 3D, if you understand what I mean. In this regard, Bob CONGRATS! you are now a BIG scientist welcome to the world of reality. Exercise the principles that you have learnt in ALL possible ways big or small and gradually you will discover your passion. The biggest mistake you can make is attempting to climb a mountain from the top. I believe its illogical anyway and you are a logic expert, having attain this fete. Good luck. Michael
  7. Hi Pablo, Can see your question really set and specific, try this case: I read that your shaft/member cuts across the changing values of YTS. I advise that you use the lowest value of the YTS. Your chart indicate 570MPa. Reasons: 1. Lowest MPa keeps you in the safe range, and you further need a safety factor applicable to the environment of operation of your member. 2. Lowest MPa ensures that no diameter of your member will run into plastic deformation. Varied plastic deformation in a member generate secondary stress within the member and this will reduce on number of load cycles that the member can withstand due to fatigue loading. Allow me to keep it that simple. No equations at this stage as requested. Kind regards. Michael
  8. Role mechanics, especially relative motion would play in facilitating migration of motion technology from the traditional fossil fuel energy to green technologies
  9. As indicated by my earlier counter part you'll need to consider bending moments and consequently bending forces on the cross member. Further to that you need to compute the direct forces on the fulcrum and forces transmitted on fulcrum members depending on its design. Detail of the system design may assist to arrive at the specifics. Regards.
  10. Mucugia

    A Calculus Challenge

    Prof, Thanks for reply, just saw it on posting final response. Waiting on your closing remark
  11. Mucugia

    A Calculus Challenge

    Hi, Submission for last Qs Small correction/ clarification for second moment of area of a full circle about its diameter is; I = (pie)(R^4)/4, There was an omission of denominator 4 in page 3 but is included in the working. Regards 1.pdf 2.pdf 3.pdf
  12. Mucugia

    A Calculus Challenge

    Prof, Find attached solution to 2nd moment of area about x-x Regards Page 1.pdf Page 2.pdf Page 3.pdf
  13. Mucugia

    A Calculus Challenge

    Hi prof, The first page continues to the third page the expression of first moment of area about o-o is as shown in the numerator expression of I/A. I deemed page 2 not to be necessary for submission, as was my rough page for working the trigonometrical identities. For purposes of clearing doubt please find it as attached. However I discourage placing it as page 2 as its bound to raise confusion on the logical flow of the solution. 3rd page is complete in my regard. I have done a test of the expression when alpha equals zero, h = R. I leave it to you to evaluate or simplify further. PAGE 2.pdf
  14. Mucugia

    A Calculus Challenge

    Hello Prof Have taken the problem from Jareck 4 Jan 19, area of enclosed area to work the centre of area. As follows: 1. The y-axis passes through the centre of area, considering the symmetry about y-y. 2. A line at h from o-o defines the position of centre of area along y-y. 3. Further detail is as in attached working. All worked from culculus first principles and using available trigonometrical identities. Regards PAGE 1.pdf PAGE 3.pdf
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