Static, quasi-static and dynamic properties

Static, quasi-static and dynamic properties: Define each category, give examples and

document whether static and quasi-static properties can be applied successfully on the

analytical and numerical study dynamic or ballistic phenomena.

Static properties:

Static properties are properties of a material that are constant and do not change with change

in the loading conditions, temperature, process variables in which the material is functioning

etc. For example, the molecular weight is a static property. Hardness can also be considered

to be a static property. Boiling point, Melting point, latent heat etc. are all static properties.

Static properties have the following characteristics:

Represent intrinsic characteristics of the material

Independent of process variables

Easy to use in non-linear problems

Quasi-static properties:

Quasi static properties are properties that are constant or nearly constant as long as the

process variables operate within a specific window. Specifically, these properties do not show

any significant deviation from their value if the operating parameters change. Examples of

quasi-static properties are compressive strength, splitting tensile strength and flexural

strength. These properties are also ones that may remain constant in a specific direction but

change in other directions. For example, stiffness and strength of PVC material subject to

tensile stress remain constant in the axial direction of the PVC fiber. Function properties can

serve as quasi-static properties that allow you to save the state of a variable related to the

function.

Quasi-static properties have the following characteristics:

Do not represent intrinsic characteristics of the material

Independent of process variables in one or more directions

Easy to use in non-linear problems when they behave as quasi-static for the range of

definition of the problem

Dynamic properties:

Dynamic properties are properties that change their value with process conditions. For

instance, the thermal conductivity has a strong dependence on temperature. Hence, for such

properties, the problem being solved must be updated with the new value of the property for

each time step. Likewise, other properties that are dynamic are heat transfer coefficient,

density, etc. are examples of dynamic properties.

Dynamic properties have the following characteristics:

Do not represent intrinsic characteristics of the material

Dependent on process variables

Difficult to use in non-linear problems

Static properties can be applied to analytical and numerical studies of dynamic and ballistic

phenomena. This is because these properties do not change with change in operating

conditions. Quasi-static properties may not necessarily be applied in dynamic and ballistic

conditions. This is because if the operating window is large enough, these properties may

change, and hence need to be updated in the analytical or numerical solution being carried

out.

References:

1. http://thyme.ornl.gov/aisi/reports/ornl-aisi-final.doc, Last accessed 24th April 2014

2. http://www.ligo-wa.caltech.edu/~robert.schofield/tmpc4paper.doc, Last accessed 24th

April, 2014