Recent content by enginecadet88

Ill give some more background. The calculations i need really don't have to go into too much detail though. This equation is for a crane trolley of 15 tonnes (metric) which moves along 2 beams. So, it is not a metal on metal contact. It will be a set of wheels or more accurately a rack and...

Homework Statement Ok so i need to choose a motor that is capable of moving 15 tonnes (metric) over a distance of 16 m at 0.2 m/s. So, I am guessing i need to first find the force required to move this object which would be F=m*a. Is this right? Now, what would be the equation to find...

My crane can't be classed as a uniformly distributed or a point load as the trolley is 4 m long itself. Therefore the weight is spread over 4 m of the total length at any time.

The proposal layout stated that the main engine room dimensions hadnt been decided so it is not known where it will go. So I've used the formula 5 WL^4/384EI. Now i need to find the power required to move the trolley along the beam so i can choose a motor.

Thanks mathmate and nvn. Been struggling with this for a while. I worked out all equations with a final deflection of 13.48mm. Due to regulations on cranes the max deflection is 1/750th of the total length so my max allowed was 21.313mm. This is great and will surely help me on my project...

Ah. Now i might be onto the right track. I have recalculated and the result for the second moment of area is now = 340033333.3 Does this not seem a little high? also, do you know the units? The 15 tonnes (metric) in Newtons is 147100.5 n.

before i try again i think i may have solved my problem. In the first part of the equation i have been using (bh)^3. Is this supposed to be h^3 then multiplied by b?

But that is my problem. The second moment of area equation i gave you in the last post gives me the answer of -1.5009x10^-4. Is this ok to be minus?? The load on the beams is 15 tonnes (metric) so that is 147112.5

The second moment of area equation on the wiki article is:- (b*h)^3 - 2(b-tw)/2 * h1^3 and then the whole equation divided by 12. So when i placed the numbers in the equation was (0.23*0.3)^3 -2 (0.23-0.03)/2 * 0.22^3 then the answer divided by 12 I have tried inputting the numbers...

Its the formula on wikipedia that's giving me the problems. The measurements are as follows h=300mm b=230mm h1= 220mm and tw=30mm. Unfortunately when putting these numbers into the second moment of area equation i come up with -1.5009x10^-4. This has a knock on effect with the other...

Homework Statement Ok. So, i have been giving the assignment of designing and testing an engine room crane for use on ship. I have designed a crane which has 2 i-beams which a trolley travels along. My questions are:- -How do i find the second moment of area of the I-beams? The equation i...