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Products  |  Engineering Mechanics and Machine Elements  |  Strength of Materials  |  FL 200
FL 200 Photoelastic Experiments with a Transmission Polariscope Show data sheet (pdf file) Print page
Technical Description

Photoelasticity is a tried and proven method of analysing and recording mechanical stresses and strains in components. It is deployed for quantitative measurement and to demonstrate complex stress states. The components used are models made of transparent, photoelastically sensitive plastic which becomes optically double-refractive under mechanical loading.

  FL 200 is used to perform photoelastic experiments on flat, transparent plastic models. The models are subjected to loading by external forces, and have circular polarised light shone through them. An analyser analyses the light which has penetrated the body.

  The experimental setup comprises the following components: A light source, four filters (to generate circular polarised light) and a frame inside which the models are attached and subjected to loading. The light source optionally permits coloured stress patterns with white light or light / dark representation with monochromatic light.

  The combination of a polarisation filter and a quarter wave plate generates circular polarised light. Behind the model is a second quarter wave plate (perpendicular to the first one), combined with a second polarisation filter. The filters are mounted on rotating bearings and provided with angle scales.

  Various models are mounted inside the frame. A load application device applies bending, tensile or compressive load to the model by way of a spindle. Stresses and strains occurring in the model are identifiable as bright spots, visualising the distribution of stress. To determine the principal stress difference, the order of the dark isochromatics is evaluated.

  FL 200 permits flexible experimental setups even with self-made models.

Learning Objectives / Experiments

- Generation of planar stress states in various

  models under load
  * bending, tensile load, compressive load
- Investigation of diffusion of stresses with plane or

  circular polarised light
- Interpretation of photoelastic fringe patterns
  * stress concentrations, zero points, neutral fibres,

     areas of constant stress, stress gradients
- Determination of occurring stresses and strains

  graphically and arithmetically


* Photoelastic experiments on models subjected to

  mechanical loading1
* Monochromatic or white-light illumination1
* Creation of stress patterns with plane or circular

  polarised light1
* Determination of principal stress difference1
* Various plastic models as accessories, e.g. wrench,

  bow, notched bars1
* Models to investigate specific issues can be easily

  made by users1
* Well structured instructional material

Available accessories
FL 200.01 -- Set of 5 Photoelastic Models
FL 200.02 -- Model - Arch
FL 200.03 -- Model - Crane Hook
FL 200.05 -- Set of 3 Photoelastic Models, Comparison of Notches
FL 200.06 -- Model - Stresses on Weld Seams
FL 200.07 -- Model - Wrench
FL 200.12 -- Photoelastic Model Material in Panels 650x400x10mm
FL 200.82 -- Ring Dynamometer 500 N
FL 200.83 -- Ring Dynamometer 1000 N
FL 200.84 -- Ring Dynamometer 2000 N
Alternative products
FL 210 -- Photoelastic Demonstration
FL 200 - FL 210 Representation of Stress Distribution
[1] Representation of mechanical distribution of stress in photoelastic experiments
[2] 2 plane polarisation filters as polariser and analyser
[3] 2 quarter wave filters to generate circular polarised light
[4] All filters with 360 angle scale and marking of the main optical axis
[5] White light generated using a fluorescent tube and two incandescent lamps
[6] Monochromatic light (colour yellow) generated using a sodium vapour lamp
[7] Filters roller bearing mounted and rotating
[8] Frame cross-arms height-adjustable
[9] Generation of compression or tension forces by means of a threaded spindle
[10] Complete models in polycarbonate (PC) for demonstration purposes available as accessories 
Technical Data

Light source
- lamp box with white diffuser
- for white light
  1 fluorescent tube TL-E 32W/33 (colour: 33)
  2 incandescent lamps, candle bulb, matt inner E14,

  235V, 25W
- for monochromatic light (colour yellow)
  1 sodium vapour lamp SOX 35, 35W
Filter, enclosed in glass, diameter: d=425mm
- 2 polarisation filters (dark olive)
- 2 quarter wave filters (colourless)
Frame w x h: 600x750mm

Dimensions and Weight
l x w x h: 800 x 600 x 750 mm
Weight: approx. 50 kg
Required for Operation
230V, 50/60Hz, 1 phase or 120V, 60Hz/CSA, 1 phase
Scope of Delivery
1 frame with load application device
2 polarisation filters
2 quarter wave filters
2 filter holders
1 light source
1 set of instructional material
Order Details
021.20000  FL 200  Photoelastic Experiments with
                    a Transmission Polariscope
© 2005 G.U.N.T. Gerätebau GmbH