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Engineering Thread

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Comments

  • #842
    Brian
    Registered Users, Registered Users 2 Posts: 5,699 ✭✭✭Brian


    mathew wrote: »
    just looked at it there.. Pretty damn funny..
    I'd say if forgot to log out tho...

    T9, busted. :cool:


  • #843
    Jonathan
    Moderators, Education Moderators, Home & Garden Moderators Posts: 8,303 Mod ✭✭✭✭Jonathan


    Baza210 wrote: »
    Are you on G0701-List?
    Being in second year, I would be on G0702-List.


    Mailing list abuse is rather amusing even if it is annoying.
    One of the class reps was publicly humiliated on ours by about 20members of the class.


  • #844
    Brian
    Registered Users, Registered Users 2 Posts: 5,699 ✭✭✭Brian


    I take it you're on the case to identify these individuals and perhaps ensure that "this will be brought further"? Hahahaha.


  • #845
    mathew
    Registered Users, Registered Users 2 Posts: 1,488 ✭✭✭mathew


    haha.. was that another student that sent that one?

    Im not on the list, was with first years tho..


  • #846
    Brian
    Registered Users, Registered Users 2 Posts: 5,699 ✭✭✭Brian


    mathew wrote: »
    haha.. was that another student that sent that one?

    Im not on the list, was with first years tho..

    Yeah, both of them are on the JF class list.


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  • #847
    Brian Dublin
    Closed Accounts Posts: 9 ✭Brian Dublin


    bit of a bogey wrote: »
    Hi, can anyone help? Im tring to select the correct motor. The motor simply has to pull a weight of 2kg. How would I calculate the required torque? The speed isint important but It probally comes into calulations somewhere? Does it relate to the torque?

    2Kg = x = 2kg over matter x torque x 2Sq rateo 100 = MARY HARNEY WITH A HARNIS 5 mph on flat gound 7 mph down hill and 1 mph up hill


  • #848
    mathew
    Registered Users, Registered Users 2 Posts: 1,488 ✭✭✭mathew


    Brian Dublin wrote: »
    2Kg = x = 2kg over matter x torque x 2Sq rateo 100 = MARY HARNEY WITH A HARNIS 5 mph on flat gound 7 mph down hill and 1 mph up hill

    wut??


  • #849
    Peleus
    Registered Users, Registered Users 2 Posts: 784 ✭✭✭Peleus


    Baza210 wrote: »
    Yeah, both of them are on the JF class list.

    that email was hilarious. embarrassing for harry and louise tho.

    ye the guy rob who sent the second email was stupid. he was clearly trying to get in with the engineering girls. "leave the engineering girls alone." "Louise is a representative of our class and should not be treated in this manner."


  • #850
    Jonathan
    Moderators, Education Moderators, Home & Garden Moderators Posts: 8,303 Mod ✭✭✭✭Jonathan


    Peleus wrote: »
    ye the guy rob who sent the second email was stupid. he was clearly trying to get in with the engineering girls. "leave the engineering girls alone." "Louise is a representative of our class and should not be treated in this manner."
    Was he being serious?


  • #851
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,265 Mod ✭✭✭✭godtabh


    What was sent around?


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  • #852
    devinejay
    Registered Users, Registered Users 2 Posts: 639 ✭✭✭devinejay


    Peleus wrote: »
    "leave the engineering girls alone."

    I agree in fairness, they're a rare and mysterious breed, I only just got one to talk to me the other day and now with all this mailing list abuse they might get scared and run away! Then how are we to find wives who can deal with our anally retentive and nerdy nature!!! Hope would be lost.....:(:rolleyes:


  • #853
    Brian
    Registered Users, Registered Users 2 Posts: 5,699 ✭✭✭Brian


    kearnsr wrote: »
    What was sent around?

    Fantasising over class reps. You know, the usual.


  • #854
    godtabh
    Moderators, Science, Health & Environment Moderators Posts: 23,265 Mod ✭✭✭✭godtabh


    Baza210 wrote: »
    Fantasising over class reps. You know, the usual.

    Not really its been awhile


  • #855
    TheAmateur
    Registered Users, Registered Users 2 Posts: 582 ✭✭✭TheAmateur


    Anyone manage to get info to compare the bending strength of timber with other materials? I've been googling for ages! I've googled bending strength, flexural strength, modulus of rupture, for steel, wood, plastic, anything! The only semi-useful page I've found so far is: http://www.matweb.com/reference/flexuralstrength.aspx
    and I'm not even sure if those are the right kind of figures. Can we just compare the Young's Modulus of the materials instead? Otherwise it just doesn't seem to make sense...


  • #856
    devinejay
    Registered Users, Registered Users 2 Posts: 639 ✭✭✭devinejay


    I had no luck on the web either, but the library turned up some decent facts, but not a lot. Mostly I ended up trawling through books on construction materials, and finding one or two useful tables. Contrary to what I expected, the best info I got was on timber, because all the standards, grades and varieties of steel made any info on flexural strength indecipherable due to the complexity of the tables.

    Can tensile strength be readily compared to flexural modulus, because I did mange to find some clear data on that.


  • #857
    mathew
    Registered Users, Registered Users 2 Posts: 1,488 ✭✭✭mathew


    That was a head wrecker last year.
    Found this site this year http://www.matbase.com/material/wood/
    Has info on all sorts of materials.
    There are obviously loads of different types of wood, all with different properties.. That'll give you and idea anyway. It was bending strengths, young's modulus, tensile and compressive strengths, density etc.
    The search on the left is pretty good too.


  • #858
    TheAmateur
    Registered Users, Registered Users 2 Posts: 582 ✭✭✭TheAmateur


    devinejay wrote: »
    Can tensile strength be readily compared to flexural modulus, because I did mange to find some clear data on that.
    Dunno, I'm actually more confused after looking through tables than I was before... wikipedia's article on flexural strength has me confused.
    EDIT: The throwing arm is made of ash isn't it?


  • #859
    devinejay
    Registered Users, Registered Users 2 Posts: 639 ✭✭✭devinejay


    TheAmateur wrote: »
    EDIT: The throwing arm is made of ash isn't it?

    Dunno actually, it certainly is similar to the wood of a hurl, but I wouldn't know enough to say for sure.


  • #860
    TheAmateur
    Registered Users, Registered Users 2 Posts: 582 ✭✭✭TheAmateur


    I remember reading what it was made of somewhere, but I've been through every document on webct and of course I can't find it now that I need it... :rolleyes:


  • #861
    Brian
    Registered Users, Registered Users 2 Posts: 5,699 ✭✭✭Brian


    I'm glad you guys are doing all of the preliminary research for me *yawn*


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  • #862
    mathew
    Registered Users, Registered Users 2 Posts: 1,488 ✭✭✭mathew


    TBH I dont think it really matters that much... :P


  • #863
    devinejay
    Registered Users, Registered Users 2 Posts: 639 ✭✭✭devinejay


    There's a pretty extensive list of hardwoods and their properties here if anyone is interested.

    Some baseball bat manufacturing company


  • #864
    TheAmateur
    Registered Users, Registered Users 2 Posts: 582 ✭✭✭TheAmateur


    Nice... how much googling did you have to do?:p
    Anyone done experiment E2? We went through the last part so fast (measurement of phase difference) I can't actually remember what we were supposed to take from it! I have "Max alpha = pi" written down in my book and a sketch of two waves canceling each other out, so something must've made sense at the time...


  • #865
    devinejay
    Registered Users, Registered Users 2 Posts: 639 ✭✭✭devinejay


    It was a lucky search I guess!

    Can't help with E2 really, I had to write up E1 so I didn't pay much attention to E2 when we did it.


  • #866
    Brian
    Registered Users, Registered Users 2 Posts: 5,699 ✭✭✭Brian


    I had to write up E2 and just skipped the part about phase difference since he didn't go through it with us either..


  • #867
    mathew
    Registered Users, Registered Users 2 Posts: 1,488 ✭✭✭mathew


    From my E2 reprot from last year:

    Theory:
    Measurement of phase difference: if two currents, two voltages, or one current and one voltage, or any other periodic phenomena have the identical frequency and both reach their peak and their zero values at the same time, they are said to be in phase with each other. If equal frequency waves reach their peaks at different times, there is said to be a phase difference between them. One precedes the other by an angle Φ.

    Procedure
    Phase Difference Measurements
    - Connect the circuit shown below
    - Set the signal generator to 500Hz at 5Vp-p
    - Calibrate the oscilloscope for equal deflections on both the X and Y-axis
    - Observe the waves
    - Repeat with frequencies of 1kHz, 2kHz, 3kHz, 4kHz and 5kHz

    Discussion
    In the fourth section of the experiment it was found that as the peak to peak values get closer to each other only one of the values changed. One of the values was set to 5Vp-p and the other value increased in small amounts until the graphs where very close to being in phase. This is due to the equation:
    <some equation>
    As the frequency increased the capacitive reactance decreased and visa-versa.

    Conclusion
    The fourth section showed how it was possible to get phase difference measurements by reading the waveforms shown.


  • #868
    TheAmateur
    Registered Users, Registered Users 2 Posts: 582 ✭✭✭TheAmateur


    mathew wrote: »
    Discussion
    In the fourth section of the experiment it was found that as the peak to peak values get closer to each other only one of the values changed. One of the values was set to 5Vp-p and the other value increased in small amounts until the graphs where very close to being in phase. This is due to the equation:
    <some equation>
    As the frequency increased the capacitive reactance decreased and visa-versa.
    I'm with you until here... I thought the idea was to show two waves out of phase, as opposed to changing one until they're in phase... suppose that'd explain the variable capacitor though. Thanks for the info btw! I've been staring at this bit for about an hour!
    Baza210 wrote:
    I had to write up E2 and just skipped the part about phase difference since he didn't go through it with us either..
    Did you lose many marks over it?


  • #869
    mathew
    Registered Users, Registered Users 2 Posts: 1,488 ✭✭✭mathew


    TheAmateur wrote: »
    I'm with you until here... I thought the idea was to show two waves out of phase, as opposed to changing one until they're in phase... suppose that'd explain the variable capacitor though. Thanks for the info btw! I've been staring at this bit for about an hour!

    TBH I dont have a clue.. Cant really remember the experiment at all.. There is a very strong chance I got it wrong. Cant find my result to see what I got tho..


  • #870
    Brian
    Registered Users, Registered Users 2 Posts: 5,699 ✭✭✭Brian


    Don't know if I lost marks, haven't gotten it back yet. Probably did though. HOWEVER, I did put quite a bit of effort into that lab report, it was like 800 words.


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  • #871
    TheAmateur
    Registered Users, Registered Users 2 Posts: 582 ✭✭✭TheAmateur


    Did a bit of creative googling and managed to find this thread from this very website, by an engineering student from trinity (afaik, I mean the experiment is identical). He seems to have actually had to do part 4 properly, but he doesn't explain how to predict the phase angles...
    Baza210 wrote:
    Don't know if I lost marks, haven't gotten it back yet. Probably did though. HOWEVER, I did put quite a bit of effort into that lab report, it was like 800 words.
    WOW! 800! Hey isn't that longer than the 1500 word assignment you did? :P


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