Analysis of buckling phenomena

Aim: To perform a buckling analysis on a cyclonic separator stand.

Description:

Finite Element Analysis

The Finite Element Analysis (FEA) method, originally introduced by Turner et al. (1956), is a powerful computational technique for approximate solutions to a variety of “real-world” engineering problems having complex domains subjected to general boundary conditions. FEA has become an essential step in the design or modelling of a physical phenomenon in various engineering disciplines. A physical phenomenon usually occurs in a continuum of matter (solid, liquid, or gas) involving several field variables. The field variables vary from point to point, thus possessing an infinite number of solutions in the domain. Within the scope of this book, a continuum with a known boundary is called a domain. The basis of FEA relies on the decomposition of the domain into a finite number of subdomains (elements) for which the systematic approximate solution is constructed by applying the variational or weighted residual methods. In effect, FEA reduces the problem to that of a finite number of unknowns by dividing the domain into elements and by expressing the unknown field variable in terms of the assumed approximating functions within each element. These functions (also called interpolation functions) are defined in terms of the values of the field variables at specific points, referred to as nodes. Nodes are usually located along the element boundaries, and they connect adjacent elements.

The finite element analysis method requires the following major steps:

• Discretization of the domain into a finite number of subdomains (elements).
• Selection of interpolation functions.
• Development of the element matrix for the subdomain (element).
• Assembly of the element matrices for each subdomain to obtain the global matrix
• for the entire domain.

• Imposition of the boundary conditions.
• Solution of equations.
• Additional computations (if desired).

Cyclone separator:

Cyclone separators are widely used to clean the air or gases from particulates, moisture, dust(ref). It consists of a cylindrical barrel followed by a conical section. In Rajasthan due to sandy soil the dust content in the air is more. It can cause abrasions to our OVAR setup and can also blocks the pores of it. In the cyclone separator air traverse in a helical path and forms a vortex. By the action of gravitational, buoyant and centrifugal forces the dust particles get separated.

For propagation of air inside the cyclone separator there is a need of blower. The power consumed by the blower is directly proportional to the pressure drop in the cyclone separator. Pressure drop depends upon the geometry of cyclone separator and velocity of air.

Objective:

• To create a metallic stiffener on the legs of the stand and run the analysis to find out the change in buckling factor of safety. 
•  To run a design study and find the optimum position for the stiffener. 

  Aim: To perform a buckling analysis on a cyclonic separator stand.

  Description:

  Finite Element Analysis

  The Finite Element Analysis (FEA) method, originally introduced by Turner et al. (1956), is a powerful computational technique for approximate solutions to a variety of “real-world” engineering problems having complex domains subjected to general boundary conditions. FEA has become an essential step in the design or modelling of a physical phenomenon in various engineering disciplines. A physical phenomenon usually occurs in a continuum of matter (solid, liquid, or gas) involving several field variables. The field variables vary from point to point, thus possessing an infinite number of solutions in the domain. Within the scope of this book, a continuum with a known boundary is called a domain. The basis of FEA relies on the decomposition of the domain into a finite number of subdomains (elements) for which the systematic approximate solution is constructed by applying the variational or weighted residual methods. In effect, FEA reduces the problem to that of a finite number of unknowns by dividing the domain into elements and by expressing the unknown field variable in terms of the assumed approximating functions within each element. These functions (also called interpolation functions) are defined in terms of the values of the field variables at specific points, referred to as nodes. Nodes are usually located along the element boundaries, and they connect adjacent elements.

  The finite element analysis method requires the following major steps:

  • Discretization of the domain into a finite number of subdomains (elements).
  • Selection of interpolation functions.
  • Development of the element matrix for the subdomain (element).
  • Assembly of the element matrices for each subdomain to obtain the global matrix
  • for the entire domain.
  • Imposition of the boundary conditions.
  • Solution of equations.
  • Additional computations (if desired).

  Cyclone separator:

  Cyclone separators are widely used to clean the air or gases from particulates, moisture, dust(ref). It consists of a cylindrical barrel followed by a conical section. In Rajasthan due to sandy soil the dust content in the air is more. It can cause abrasions to our OVAR setup and can also blocks the pores of it. In the cyclone separator air traverse in a helical path and forms a vortex. By the action of gravitational, buoyant and centrifugal forces the dust particles get separated.

  For propagation of air inside the cyclone separator there is a need of blower. The power consumed by the blower is directly proportional to the pressure drop in the cyclone separator. Pressure drop depends upon the geometry of cyclone separator and velocity of air.

  Objective:

  • To create a metallic stiffener on the legs of the stand and run the analysis to find out the change in buckling factor of safety. 
  •  To run a design study and find the optimum position for the stiffener. 

• Figure: Flow of the project.

  Steps Followed:

  • 3D CAD Models are created on the basis of the drawings provided by skill Lync.
  • Simulation add-in is selected and a new buckling study is created.
  • Material is provided to the model as alloy steel(default).
  • Fixed constraint is provided on the bottom of the legs of the stand.
  • External force is provided as a uniformly distributed load on the upper surface.
  • Discretization is done using the meshing command.
  • Study is run and results are saved.
  • Results are studied and a factor of safety plot is defined.
  • A design study is created to maximize the factor of safety.

  Results:

  Case 1: Cyclone separator stand without stiffener.

  
  
  • Figure: Stress Plot.

    Figure: Factor of safety without stiffener

    Case 2: Cyclone separator stand with stiffener.

    Figure: Design study table.

    Figure: Offset v/s Factor of safety.

    Conclusions:

    The stiffener at 900 mm provides the maximum factor of safety. So it would be the best position to provide the stiffener