ROTATING BENDS 1

[SeanSweeney]

IF I HAVE A 30 DEGREE BEND IN THE HORIZONTAL I AND BEGIN TO ROTATE IT DOWNWARDS TOWARDS THE VERTICAL. THE 30 DEGREES BEGINS TO REDUCE AND CONSEQUENTLY THE VERTICAL BEND ANGLE BEGINS TO GROW.

IS THERE A CALCULATION OR PROGRAMME WHICH CAN HELP ME FIND OUT THESE VALUES.

THANKS

 

[SlideRuleEra]

The horizontal angle is a function of the cosine on the rotated angle. The vertical angle is a function of the sine of the rotated angle.

Per your example, rotate your 30 degree bend by, say, 20 deg downward:

Horizontal Angle = (30 deg) x (cos 20 deg) = 28.2 deg

Vertical Angle = (30 deg) x (sin 20 deg) = 10.26 deg

Readily adaptable to a spreadsheet.

http://www.SlideRuleEra.net

 

[SeanSweeney]

Sliderule - thanks for your reply - it make sense but when I draw a line in AutoCAD and rotate it 20 degrees it leaves me 28.48 degrees in the horizontal and gives me 11.17 in the vertical.

There are fairly close but should be the same - any ideas. The maths is correct like you say.

 

[shanej]

Let B be the bend angle (30deg)
Let R be the rotation angle
Let Ha be the apparent horizontal angle (viewed from above)
Let Va be the apparent vertical angle (viewed from the side)

tanHa =tanB*cosR
tanVa =tanB*sinR

20 deg rotation:
tanHa =tan30*cos20=0.577*0.9397=0.536 (Ha=28.19deg)
tanVa =tan30*sin20=0.577*0.342=0.197 (Va=11.17)

 

[stanier]

try

http://www.pipingdesign.com.

They have a few tools and charts that cover this sort of thing for pipe fittings.

 

[rossmail]

you must calculate the true angle (*)useing the grade in (A)grade out (B)and horizontal angle (C).
cos*=cos A cos B cos C +(if grade in and grade out has one above horizon and one below horizon)-(if both above or both below horizon ,example grade in -5%grade out +8% or grade in +5% grade out-6%)sinA sinB ,then you can calculate the roll for this bend to get the proper vertical angle and grade.its a common calculation when working out the stell pipe mitre cut bend fabrication.

 

[rossmail]

send me the horizontal angle (from above )grade in % (pos or neg)to the bend and grad out % (pos or neg)from the bend and i will send you the true angle and roll ,i have a program ,i can also give you the max cut to make this bend and templet layout ,i have looked high and low but havent found another program anywhere .i could fax you an example of the calculations but its hard to do on this

 

[rconner]

If you would like to see an online picture or diagram to help explain some of this behavior/these descriptions, you could perhaps look at pages 17-25 and 26 at

http://www.acipco.com/adip/products/Sect17.pdf.