mezza-canuck
New Member
Hey, can any one explain method of sections and method of joints?? i can't seem to figure it out??:mad1::mad1::mad1::mad1::mad1::mad1::mad1:
Plz help
Plz help
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HELP!! Method of sections/joints (2 Viewers)
- Thread starter mezza-canuck
- Start date
twilight1412
Member
section - what something looks like if you cut it from A to B (they will label it)
usually fill in whatever has been cut through with lines at an angle of 45 with even spacing also webs are not filled never ever
joints
well cant help you here i havent learnt it yet =P
usually fill in whatever has been cut through with lines at an angle of 45 with even spacing also webs are not filled never ever
joints
well cant help you here i havent learnt it yet =P
yew_315
Oldie
is this for truss analysis?
if it is, wat do you need to know about it?
(i didn't do engo studies in HSC, but i've done trusses at uni, hence a bit of specifics is needed)
if it is, wat do you need to know about it?
(i didn't do engo studies in HSC, but i've done trusses at uni, hence a bit of specifics is needed)
mezza-canuck
New Member
Its for trusses yeah, like bridges
FuelPumpingEngn
Member
method of sections is just like using moments. You must cut the truss through at least 3 members, 1 being the member that you want to find out. You then ONLY look at one side of the truss taking moments from the joint where the member that you want to find is NOT connected to but the other 2 members that you cut are connected to. You then perform moments using the perpindicular distances of each force from one side of where u cut the truss.
Before doin all this you must first find the reactions tho
hope that help
Before doin all this you must first find the reactions tho
hope that help
wingman
Let's Rock N' Roll
There are two methods to determine internal forces in members. Method of Joints and Method of Sections.
First, understand the concept. The assumption you are working with is if the bridge is in equilibrium, then any joints must also be in equilibrium (ie no net movement).
at every joint, you need to do a force component balance (in the x and y directions). therefore, if you have a member running at 60 degrees, then you need to break that force member to horizontal and vertical components of the same force. then you sum all the force in vertical plane that acts on that joint only, and likewise for horizontal. Its not easy to explain without diagrams or step by step.
method of section is abit harder. you need to cut the truss in the right place. and choose one side to work from (not both). Once you chosen a side(usually the side with less members i think, unique to Q) you disregard the other side. you draw in arrows on the cutted members to assume if they are Tension/compression. then you do a moments about a point where all the members cut (but 1) align up to, so you can work out the moment of the member (the 'but 1' one)... thats the gist of it.
Need more explanation. email me. lil_honki@hotmail.com
Chosta
First, understand the concept. The assumption you are working with is if the bridge is in equilibrium, then any joints must also be in equilibrium (ie no net movement).
at every joint, you need to do a force component balance (in the x and y directions). therefore, if you have a member running at 60 degrees, then you need to break that force member to horizontal and vertical components of the same force. then you sum all the force in vertical plane that acts on that joint only, and likewise for horizontal. Its not easy to explain without diagrams or step by step.
method of section is abit harder. you need to cut the truss in the right place. and choose one side to work from (not both). Once you chosen a side(usually the side with less members i think, unique to Q) you disregard the other side. you draw in arrows on the cutted members to assume if they are Tension/compression. then you do a moments about a point where all the members cut (but 1) align up to, so you can work out the moment of the member (the 'but 1' one)... thats the gist of it.
Need more explanation. email me. lil_honki@hotmail.com
Chosta
yew_315
Oldie
i'm not a big fan of sections. it requires a fair bit of practice, and also requires the right circumstances, although, if u r good at it, it'll make things quicker.
i prefer joint analysis. it's longer, but it's easier. u have to make sure that for each joint, it has to have only 2 unknown forces and 1 known force acting on the joint. then just split it up into x and y components and solve the two unknowns. you may need to do some trig, but it's pretty basic stuff. you just need to choose the order in which you analyse the joints. global equilibrium is sometimes easier. But it is very conditional. and that's only really for analysing the reaction forces. but it can sometimes be a good way to start. All you hav to do is take in the x, y and moment equations around any point you choose.
anyway, hope it helps!
i prefer joint analysis. it's longer, but it's easier. u have to make sure that for each joint, it has to have only 2 unknown forces and 1 known force acting on the joint. then just split it up into x and y components and solve the two unknowns. you may need to do some trig, but it's pretty basic stuff. you just need to choose the order in which you analyse the joints. global equilibrium is sometimes easier. But it is very conditional. and that's only really for analysing the reaction forces. but it can sometimes be a good way to start. All you hav to do is take in the x, y and moment equations around any point you choose.
anyway, hope it helps!