Analysis of buckling phenomena
AIM: To analyze the buckling load for the support stand of the cyclonic separator stand under different cases and to find a proper case to ensure high safety.
Theory:
Buckling is the sudden change in shape of a structural component under load such as the bowing of a column under compression or the wrinkling of a plate under shear.
The buckling load factor is the factor of safety of the component under buckling. The factor is the ratio of the buckling loads to the applied loads. In order to ensure safety from the catastrophic effect of the buckling failure, it is mandatory to have a buckling load factor to be more than 3 atleast.
Implementation:
Case 1:
Here from the step file of the cyclonic seperator, stand is seperated and then initially analyzed for the buckling by taking the load of 150KN on the top face of the stand in the downward direction vertically and fixing the bottom 4 ends of the stand legs which will be in the contact with the ground. The material was considered to be an alloy steel with the inbuilt properties for the materials in the solidworks. Later the mesh was created to be finer and then the simlation was ran. As a result, the buckling safety factor was found to be around 9.35 stating that the component was safe.
The factor can be increased more by adding a stiffener to the stand at the perfect location in order to make the maximum use of the additional support.
Case 2:
In this case a stiffener was added to the stand by extruding a plate by making contact with 4 legs of the stand with a thickness of 75mm and at a distanace of 1m from the top face.
Now the material here is again cinsidered as the alloy steel and the load of 150KN acts on the top face in the downward direction were the lower bottom of the 4 legs of the stand are fixed. Then the mesh so is generated to be finer in ordr to increase the accuracy of the results as the number of elements would increase. The result obtained states that the buckling load factor to be about 27.53 i.e. the component is safe.
This location of the stiffener wass put on purpose as the total length of the leg is about 2m. It is better to find the position of the stiffener on an iterative manner using the design study feature in solidworks that helps in the optimization of the results.
Case 3:
Now the design study feature is used in order to find the best position of the stiffener on the stand in order to get theh best result i.e. the best safe design. Here the new design study is made by feeding the offset value as a variable and showing the solver which value is to be taken as offset from the model. Then set the constraints to buckling load factor from the simulation data of the previous case, then the goals to be set again to buckling load factor in order to find the best possible combination of the offset so that the factor is really high above the contraint value. Now after the simulation runs, a tabulated result is observed where the optimum case is highlighted to state the best possible case.
The best optimum case with a load of 150 KN of alloy steel material and the bottom 4 legs to be fixed, is the buckling load factor to be of 27.53 stating the best safe design and location of the stiffener. (Highlighted in green)
Case 4:
As we have varied the offset value in the previous case, now along the offset even the thickness of the stiffener is varied in order to find the best combination to withstand the 150KN load on the top face of the stand with the bottom of the 4 legs to be fixed and the material considered to be as alloy steel. Here the variables are offset and thickness where the respective dimensions were selected for the variables, then the contraints and goals are similar to that in case 3. Here in this case, there are 2 parameters to be varied and a perfect combination is to be obtained from all the possibilities.
It is observed from the results that the stiffener would be so effective at the mid length of the stand leg and also as thickness of the stiffener increases the buckling load factor also increases respectively. So the best combination is that at an offset of 1000mm and of 100mm thickness gives a maximum factor of 31.36 stating that the safety of the component is very high. (Highlighted in green)
MESH
The mesh was all the cases was considered to be same where a finer mesh was selcted for the simulation in order to have a better accuracy in the results.
Conclusion:
From the above 4 cases it is observed that stiffener is needed to increase the buckling load factor as it provides additional strength/support to the component. The optimum location to make use of the stiffener at it's maximum possible range is at the mid length of the stang legs there by stating that the safety at that loaction is high.