Lextreme II
Just call me "Lex"
- Messages
- 12,033
- Location
- City of Halos
Just thinking about making a trike powered by 1UZFE. Should round or sqaure tubes? What are the advantages and disadventage of both and what size i should use..
Round or Square Tubes
- Thread starter Lextreme II
- Start date
The 1UZFE EGR Delete Kit is available for sale here.
Solid bar stock is marginally stronger than tube, the strength property of the material comes from the wall thickness. It also determines how stiff in just about any direction it will be.
I will post some pictures in a few days of our tube chassis for our Formula SAE car that we are currently building. We use a mixure of round (mostly) and square (suspension points) tube. It is built mostly from 1" OD 4130 steel .028 and .035 wall thickness. There are a few tubes that have a thicker wall thickness than that, but those are mainly roll hoops and high load areas (bellcrank mounts)
cyberdiamond
Member
- Messages
- 158
- Location
- Adelaide Australia
A couple of trikes I have ridden have been round tube and the coolant flows through it.
Pro
New Member
- Messages
- 1,574
- Location
- Republic of Western Australia
i would use tube because it looks better, but SHS has better non-crush and non-twist properties.
autocol
New Member
- Messages
- 25
- Location
- melbourne, australia
there's a reason trees are round, and it's not luck: circles are the most efficient use of material for strength, by weight, if the material will come under load from many directions.
the strength of a beam is governed by the material properties, and the cross-sectional shape of the material, which is the second moment of area (or inertia, depending who you ask). in a nutshell, the second moment of area is a measure of the cross-sectional shape's resistance to bending in certain directions. circles are obviously equally strong in all directions, when a rectangle is strong when bending across the short edge, and weaker when bending across the long edge.
the greater the second moment of area, the greater the resistance to bending. a shape with a lot of material a long way from the center of area of the shape will have a high second moment of area. that's why a certain weight of hollow tube is MUCH stronger than the same weight of solid bar. the material is further from the center of area.
for a design that won't be engineered in full, where the resolution of forces is unknown, you're definitely better off with tube, because it's equally strong in all directions. take a look at light-aero, hardcore 4WD offroaders, sprint cars, etc - all pastimes that involve "homemade" steel frames in high stress situations - and all use 4130 chromoly steel TUBE almost exclusively.
Pro - tube will resist twisting more effectively than an SHS section of equal mass per unit length. not sure about the crushing point. probably depends on which direction you're trying to crush it: flat-to-flat or corner-to-corner...
the strength of a beam is governed by the material properties, and the cross-sectional shape of the material, which is the second moment of area (or inertia, depending who you ask). in a nutshell, the second moment of area is a measure of the cross-sectional shape's resistance to bending in certain directions. circles are obviously equally strong in all directions, when a rectangle is strong when bending across the short edge, and weaker when bending across the long edge.
the greater the second moment of area, the greater the resistance to bending. a shape with a lot of material a long way from the center of area of the shape will have a high second moment of area. that's why a certain weight of hollow tube is MUCH stronger than the same weight of solid bar. the material is further from the center of area.
for a design that won't be engineered in full, where the resolution of forces is unknown, you're definitely better off with tube, because it's equally strong in all directions. take a look at light-aero, hardcore 4WD offroaders, sprint cars, etc - all pastimes that involve "homemade" steel frames in high stress situations - and all use 4130 chromoly steel TUBE almost exclusively.
Pro - tube will resist twisting more effectively than an SHS section of equal mass per unit length. not sure about the crushing point. probably depends on which direction you're trying to crush it: flat-to-flat or corner-to-corner...
Pro
New Member
- Messages
- 1,574
- Location
- Republic of Western Australia
from your response i'll stand corrected!!!
That couldn't be more wrong.autocol said:
Solid bar stock is marginally stronger than tube, the strength property of the material comes from the wall thickness. It also determines how stiff in just about any direction it will be.
I will post some pictures in a few days of our tube chassis for our Formula SAE car that we are currently building. We use a mixure of round (mostly) and square (suspension points) tube. It is built mostly from 1" OD 4130 steel .028 and .035 wall thickness. There are a few tubes that have a thicker wall thickness than that, but those are mainly roll hoops and high load areas (bellcrank mounts)
SCV8
New Member
- Messages
- 375
- Location
- Mill Creek, WA
Yeah, tubing is used in most construction projects, as the strength/weight is far superior...
The square tube is much easier to work with, so if it's a fast project, that'd be the way to go, but if a more pure design, lighter construction is required, the round tube is stronger, but takes longer to fit, jig/clamp during the build.
Then there's oval tubing...
Oh, BTW, the Ferrari F40 used square tubing, and that car worked/handled alright.
The square tube is much easier to work with, so if it's a fast project, that'd be the way to go, but if a more pure design, lighter construction is required, the round tube is stronger, but takes longer to fit, jig/clamp during the build.
Then there's oval tubing...
Oh, BTW, the Ferrari F40 used square tubing, and that car worked/handled alright.
Similar threads
