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You are here: Home / Mechanical Engineering / Solid Mechanics / Photoelasticitimetry / EXPERIMENTAL AND DEMONSTRATION POLARISCOPE ER220


The ER220 Polariscope is a powerful tool for teaching and demonstration of stress analysis using the photo elastic technique.


It is placed on an overhead projector (not supplied), with the image projected on to a screen, and, used either in a laboratory or a lecture theatre, allows a striking demonstration of the stress fields in the loaded models.
It is also designed for quantitative work for tensile, compressive or flexural loading.
A system – unique to this unit – also allows the simultaneous rotation of the polarizer and the analyser for the isoclinal lines study.
The Polariscope consists of the following elements :
- A model-loading frame.
- An elastic load-measuring device, which uses a steel spring beam, and a micrometer dial gauge. The
device has a linear deflexion/load relation-ship.
- A rotatable circular polarizing unit, in a graduated mount, carried on runners under the loading frame.
A quarter ware plate.
- A rotatable circular analyser can be rotated through 180°.
The three units are carried on a pillar integral with the loading frame. The polarizer and the analyser are
coupled so that they may turn simultaneously.
- A set of fixtures required for the application of the loads to all the models supplied.
- A set of models in the appropriate photo elastic material for example, a disk, a ring, a beam, etc…
- Polarizer diameter : 200 mm
- Model loading area : 190 x 220 mm
- Light source : standard overhead projector source (white light). Monochromatic light obtained with green
filter swung into path of light beam.
- Maximum load on models : ± 40 kg.


Teaching objectives

- Observation of the stress concentration
- Study of strength of materials
- Structures analysis in civil engineering

Fields of application :
- Strength of materials,
- Structures, civil engineering and architecture.
- Applied mechanics, machine design, and welding technology,
- Soil mechanics,
- Biomechanics.


Dimensions and weight

- 420 x 320 x 350 mm

- Net weight : 4 kg.


Essential requirements

Additional Equipment required :
Overhead projector.

Complementary equipment :
Analogue field plotters, 24 channels, ref. ER300.
This unit can be used in conjunction with the Polariscope for the separation of the principal stresses.