ANSYS is one of the leading commercial finite element programs in the world and can be applied to a large number of applications in engineering. Finite element solutions are available for several engineering disciplines like statics, dynamics, heat flow, fluid flow, electro magnetics and also coupled field problems.

Static analysis of ANSYS:A static analysis calculates the effects of steady loading conditions on a structure, while

ignoring inertia and damping effects, such as those caused by time-varying loads. A static analysis can, however, include steady inertia loads (such as gravity and rotational velocity), and time-varying loads that can be approximated as static equivalent loads (such as the static equivalent wind and seismic loads commonly defined in many building codes).

Static analysis is used to determine the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. Steady loading and response conditions are assumed; that is, the loads and the structure's response are assumed to vary slowly with respect to time. The kinds of loading that can be applied in a static analysis include:

Externally applied forces and pressures Steady-state inertial forces (such as gravity or rotational velocity)

Imposed (non-zero) displacements

Temperatures (for thermal strain)

Fluences (for nuclear swelling)

Dynamic analysis of ANSYS:

Modal Analysis: Determining the mode frequencies and mode shapes of structures. Harmonic Analysis: Analyzing the steady-state behavior of a structure subject to cyclic

loads. Transient Analysis: Determining the dynamic response of a structure under more

general time-dependant loads. Spectral Analysis: Studying the response of structures under the action of loads with

known "spectra" (eg. random loading conditions).

The basic equation used to perform dynamic analysis is --- (i)In the above equation M, C and K denote the structural mass, damping and stiffness matrices. The vectors of nodal accelerations, velocities and displacements are , and u respectively. f(t) is the vector of applied forces

Modal analysis: Modal analysis is a linear dynamic-response procedure which evaluates and superimposes free-vibration mode shapes to characterize displacement patterns. Mode shapes describe the configurations into which a structure will naturally displace. 

The goal of modal analysis in structural mechanics is to determine the natural mode shapes and frequencies of an object or structure during free vibration. In modal analysis the right hand side of the equation of motion (i) is considered to be zero, i.e. f(t) = 0.

Modes are inherent properties of a structure, and are determined by the material properties (mass, damping, and stiffness), and boundary conditions of the structure. Each mode is defined by a natural (modal or resonant) frequency, modal damping, and a mode shape (i.e. the so-called “modal parameters”). If either the material properties or the boundary conditions of a structure change, its modes will change.

The observed displacement at angular frequency ωnis called an “operating deflection shapes” also called mode shapes.

• If you don’t specify constraints, ANSYS will calculate rigid body modes (zero frequency).

• The roots of this equation are wi2, the eigenvalues, where i ranges from 1 to number of

DOF, the square roots of the eigenvalues are ωi, the structure’s natural circular frequencies (radians/sec). Natural frequencies fi are then calculated as fi = ωi /2π (cycles/sec). Mode expansion:

• Expanding modes allows you to view them in the postprocessor.• Number of modes is usually the same as the number extracted.

Transient Dynamic Analysis A transient dynamic analysis is a technique which is used to determine the time history

dynamic response of a structure to arbitrary forces varying in time. On the right hand side of equation (1) any function for the load vector may be specified, i.e. f (t) = f (t) This type of analysis yields the displacement, strain, stress and force time history response of a structure to any combination of transient or harmonic loads.

Harmonic Response Analysis

Any sustained cyclic load will produce a sustained cyclic response in a structure which is often called a harmonic response. The harmonic response analysis solves the equation of motion (1) for linear structures undergoing steady-state vibrations. All loads and displacements vary sinusoidally with the same known frequency although not necessarily in phase. For the function of applied force on the right hand side of the equation of motion (1) the following expression is

used, i.e. . In this formulation fmax represents the amplitude of the force, Ω denotes the imposed circular frequency measured in radians/time and ψ stands for the force phase shift which is measured in radians.

Thermal Analysis:

Thermal analysis deals with heat flow in a solid body, so there must be a way for heat to enter and to exit that solid body. If heat enters a body with no way to exit, the body's temperature would theoretically rise to infinity.

Heat is flowing inside a solid and heat entering and leaving the solid, are governed by different mechanisms. Heat inside a solid moves by conduction while heat entering or escaping the solid moves by convection, or radiation, or both.

The primary unknowns are temperatures at nodes of the finite-element mesh. Temperature is scalar so it needs only one degree of freedom at each node, whether the model is 2D or 3D and regardless what elements mesh the model. Once temperatures are found at the nodes, they are interpolated over elements to calculate temperatures in the entire model.

Heat transfer by conduction, for example, is heat flowing through a

wall. It is described by: Qconduction = KA(Thot –Tcold)/L where Qconduction =

rate of heat flow, K= thermal conductivity, A = area of the wall, Thot =

temperature on the hot side, Tcold = temperature on the cold side, and L =

wall thickness.

Heat transfer by convection moves heat to or from an external face

of a solid body and surrounding fluid, such as air, water, or oil. The heat

moved by convection is described by: Qconvection = hA(Ts–Tf)

where Qconvection = flow rate by convection, h= convection coefficient, Ts =

surface temperature, and Tf = fluid temperature.