Welcome to our column design guide that prepared by Mechanical Base engineers. You can design your structural circular columns that are loaded centricaly. What you need to do is, just follow the steps below to obtain a required diameter for your structural column. There are bunch of calculators that you can use to calculate the values rapidly. Also formulae of these calculators are provided, you can use hadn calculations. Lets start…
Step 1: Specify The Pa, N, L, K, E, Sy And Shape Of Your Column
These value are essential values for column diameter calculations. These value about your colum design must be specified correctly, which depends on your engineering abilities.
Pa: Pa is the allowable load in the units of Newtton(N), which states the maximum possible load that you column will carry.
N: N is the safety factor, unitless, it chages with various kinds of factors related you situation such as the quality of material that you used, environmental variables etc. Define a logical safety factor for your system.
L: L is the length of your column has the unit of meters.
K: This is the K factor for your column that you can select according to the type of your end fixity of your column. Click on the given link to define your K factor. This is a unitless value.
E: Elasticity modulus of your column’s material. The unit is N/(m^2).
Sy: Yield strength value of your column’s material. The unit is N/(m^2).
Shape: This is the most important parameter that we prepared our calculators according to the circular cross sectional shapes. But we explain how to make your calculations for other cross sectional shapes.
Step 2: Calculate The Column Constant Of Your Column
It is a very simple unitless parameter that you can calculate bu using column constant calculator. You must use the elasticity modulus and yield strength of your column material.
Step 3: Assume That The Column Is Long
To start calculation, we need to start with an assumption that the column is long. The required shape calculation changes for long and short columns in engineering.
For long columns, Euler’s equation is used. Here we prepared a calculator that you can use for your circular cross section columns. Enter the required parameters inside the brackets, then click on ‘Calculate’ button. If you want to do teh calculation again, click on ‘Reset’ then re-enter the values then click on ‘Calculate!’. Result will give the diameter of your column.
Long Column Diameter Calculator
The formula of this calculator is like that;
But this formula is for only circular columns that you understand from that you are calculation tha diameter ‘D’ value. If you have a different shaped cross section, you can use this Euler’s formula;
In here, ‘I’ is the moment of inertia of your cross section. You need to know the formula of your moment of inertia of your column’s cross section. There are some cross section’s moment of inertia value in given link.
You can derive the required dimensional values of cross section of your column from this formula. Just enter the required values inside it.
Step 4: Calculate Slenderness Ratio And Compare It With Column Constant
You can calculate slenderness ratio of your column from this link. Then compare this with your radius ‘r’ value that you found from above calculator.
Does the slenderness ratio is bigger than column constant?
If the answer is ‘Yes’, the assumption of ‘long column’ that we made above is true, and your calculater diameter is the required diameter for your column design.
If the answer is ‘No’, your assumption of ‘long column’ is wrong, your column is ‘short column’, thus you need to do your calculations by using Johnson’s formula below.
Step 5: Re-calculation For Short Columns
If your assumption of ‘long column’ is not true, just use the Johnson’s formula for short columns. The ‘Result’ will give you the diameter of your column again.
Short Column Diameter Calculator
Johnson’s formula for short columns is like that;
The calculator just above is the calculator of above formula. We are just using yield strength of column material here.
Step 5: Re-calculate The Slenderness Ratio
After the recalculation of slenderness ratio with the new values, compare this result with column constant again.
Does thhe column constant is bigger than slenderness ratio?
If the answer is ‘Yes’, column is short and the diameter value that you found with Johnson’s formula is correct.
If the answer is ‘No’, slenderness ratio and the column constant are nearly equal to each other. So, the values from Euler’s equation and Johnson’s equation are equal.
First of all, MB does not accept any responsiblity from your calculation that you done here. All the calculated values are liability of the users of these calculators.
Take a look at our other engineering calculators avaliable in Mechanical Base!
As a good engineer, you need to take care about your units. Proper set of units will give you proper engineering calculations. If you must convert your units into proper sets of units for calculations, you can use MB-Unit Converter tool.
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