Model fabrication and Loading• 3-D model of the joint comprising a ball insert , base ring bush base ring block are fabricated by using Epoxy resin (ArlditeCY-230) and hardener (HY-951).• The fabricated parts are assembled and loaded and stress frozen.
Model fabrication and stress freezing• A suitable force is applied using dead weight along the ball centre.• After stress freezing, the slices are cut from the stress frozen model along the loading plane, where the stress is maximum.
Principle of optical equivalence• The retarder introduces the retardation equivalent to the one introduced by 3-D model.• The azimuth of the exit light ellipse may not be the same as that for for a 3-D model.the necessary correction is done by the rotater.• The parameters representing the retarder and rotater are the experimental parameters to be determined in integrated photoelasticity.
Principle of optical equivalence• The retardation is termed as characteristic retardation and denoted by 2∆• The orientation of the retarder is termed as the primary characteristic direction denoted by the symbol θ.• An idealised optical element, which simply rotates the azimuth of the light ellipse is specified by the angular rotation γ
Principle of optical equivalence• The angle γ is termed as characteristic rotation.• the summary is as follows:• Once the retardation and rotation is known at the point of interest, jones matrix can be constructed.• Suppose take problem in which stress distribution is known along the light path.
Integrated photoelasticity• Then analytically jones matrix can be written for each of the planes and multiply of them.• This gives the final jones matrix and compare this with the jones matrix which is written from experimental values and find the parameters related to stress distribution.
Integrated photoelasticity• So we need to assume stress distribution field reasonably well with several coefficients, and find the necessary number of equations equal to coefficients.• Hence we need multiple optical paths and multiple collection of charecteristic parameters so it becomes mathematically intensive.