innovator
Automotive
- Jan 31, 2002
- 25
Hello,
I am new to FEA and I am using a package ( ) to analyse a spaceframe chassis I built ( Morris Minor )
I require some help with the cross sectional details of the material.
The program asks for the following:- (I am using the metric units)
"
Ax : the Cross Sectional Area in [cm2] or [inch2]
Ix : the Cross Section Moment of Inertia about the x axis in [cm4] or [inch4]
( as a result of a Load along the local y-axis )
Iy : the Cross Section Moment of Inertia about the y axis [cm4] or [inch4]
( as a result of a Load along the local z-axis )
It : the Cross Section Torsional Constant [cm4] or [inch4]
(as a result of a Moment round the local x-axis)
For a round section the Torsional Constant is equal to the polar Moment of Inertia.
For thin walled steel profiles It = n/3 sum(hi . ti^3)
Where n depends on the type of the section:
n = 0.99 for L-sections
n = 1.31 for I-sections
n = 1.12 for U-sections
ex : the distance from the neutral line of the Member to the outside of the Member along the main axis of that Member. In the case of asymmetrical Cross Sections this will usually be the longest distance.
ey : the distance from the neutral line of the Member to the outside of the Member along the secondary axis of that Member.
et : for closed sections et is the greater of ex or ey. In the case of open sections et is the thickness of the thickest part of the section. This usually is the maximum flange thickness of the beam cross section.
For both ex and ey it is important to use the longest distance to the outside of the member as shown in the figure below.
M : the Mass of the Member per meter [kg/m] or [kg/ft]
The sizes of my round tubes are as follows:
38.1 dia x 2.642 mm wall
38.1 dia x 2.032 mm wall
34.925 dia x 1.626 mm wall
Can you convert these into the data I require? I can manage the cross sectional area but the rest is a bit beyond me.
I also have to input my material. The program asks for:-
Each Material is defined by:
E : the Modulus of Elasticity in [kN/cm²] or [Kips/inch²]
G : the Shear Modulus in [kN/cm²] or [Kips/inch²]
G = E / 2(1+v) with v = Poisson constant;
for metals v = ±1/3
Re : the Limit stress of the material in [N/mm²] or [Kips/inch²] = 0.7 Yield Point or Tensile Strength.
The Linear Coefficient of Expansion in 1/10^6 1/K
My material is CDS 2 / CFS-3 GBK bright as drawn. My welding is my Tig which apparantly reduces its strength.
Any help would be appreciated,
Thank you
John
I am new to FEA and I am using a package ( ) to analyse a spaceframe chassis I built ( Morris Minor )
I require some help with the cross sectional details of the material.
The program asks for the following:- (I am using the metric units)
"
Ax : the Cross Sectional Area in [cm2] or [inch2]
Ix : the Cross Section Moment of Inertia about the x axis in [cm4] or [inch4]
( as a result of a Load along the local y-axis )
Iy : the Cross Section Moment of Inertia about the y axis [cm4] or [inch4]
( as a result of a Load along the local z-axis )
It : the Cross Section Torsional Constant [cm4] or [inch4]
(as a result of a Moment round the local x-axis)
For a round section the Torsional Constant is equal to the polar Moment of Inertia.
For thin walled steel profiles It = n/3 sum(hi . ti^3)
Where n depends on the type of the section:
n = 0.99 for L-sections
n = 1.31 for I-sections
n = 1.12 for U-sections
ex : the distance from the neutral line of the Member to the outside of the Member along the main axis of that Member. In the case of asymmetrical Cross Sections this will usually be the longest distance.
ey : the distance from the neutral line of the Member to the outside of the Member along the secondary axis of that Member.
et : for closed sections et is the greater of ex or ey. In the case of open sections et is the thickness of the thickest part of the section. This usually is the maximum flange thickness of the beam cross section.
For both ex and ey it is important to use the longest distance to the outside of the member as shown in the figure below.
M : the Mass of the Member per meter [kg/m] or [kg/ft]
The sizes of my round tubes are as follows:
38.1 dia x 2.642 mm wall
38.1 dia x 2.032 mm wall
34.925 dia x 1.626 mm wall
Can you convert these into the data I require? I can manage the cross sectional area but the rest is a bit beyond me.
I also have to input my material. The program asks for:-
Each Material is defined by:
E : the Modulus of Elasticity in [kN/cm²] or [Kips/inch²]
G : the Shear Modulus in [kN/cm²] or [Kips/inch²]
G = E / 2(1+v) with v = Poisson constant;
for metals v = ±1/3
Re : the Limit stress of the material in [N/mm²] or [Kips/inch²] = 0.7 Yield Point or Tensile Strength.
The Linear Coefficient of Expansion in 1/10^6 1/K
My material is CDS 2 / CFS-3 GBK bright as drawn. My welding is my Tig which apparantly reduces its strength.
Any help would be appreciated,
Thank you
John