Objectif
THE OBJECTIVE OF RESEARCH PROJECT IS TO INCREASE THE EUROPEAN SPECIES CONSUMPTION AND REDUCE THE ENERGY CONSUMPTION IN MECHANICAL PULPING.
THE RESEARCH WILL BE UNDERTAKEN ON THREE DIFFERENT SPECIES:
- A EUROPEAN HARDWOOD LIKE BEECH (FAGUS SYLVATICA)
- A EUROPEAN SOFTWOOD LIKE SPRUCE (PICEA SP.)
- A TROPICAL SPECIES OFTEN IMPORTED AS A COMPARISON.
THE MECHANICAL TESTS WILL BE DONE WITH TWO DIFFERENT TECHNIQUES :
- CLASSICAL EXTENSION MEASUREMENTS
- LASER INTERFEROMETRY.
THE CLASSICAL EXTENSOMETRY WILL BE DONE ON ONE OR SEVERAL MODIFIED TENSILE TESTERS WORKING IN THE RANGE 0.1 TO 10 KILOHERTZ. THIS WILL RESULT IN MEASURING THE ENERGY CONSUMED IN TAKING THE SAMPLE TO FRACTURE.
"SPECKLE" TECHNIQUES USED IN THE LASER INTEFEROMETRY ALLOW THE FIELD OF DEFORMATION TO BE RECONSTITUTED ENTIRELY AND THE EVOLUTION OF THE DEFORMATION TO BE FOLLOWED DURING THE RELAXATION PHASE.
THE PASSAGE FROM THE DEFORMATION CORRESPONDING TO THE MAXIMUN CONSTRAINTS (EQUAL TO A SHOCK FORCE) TO THE CONFIGURATION RESULTING AFTER A LONG INTERVAL OF REPOSE WILL GIVE A MEASURE OF THE ENERGY APPLIED WHICH IS RELEASED DURING RELAXATION (AND IN FACT, TRANSFORMED INTO HEAT).
THE SAMPLE DIMENSIONS ARE SIMILAR TO MILL CHIPS (4 MM THICK, 20 MM LONG AND WIDE)
THE FOLLING PARAMETERS WILL BE STUDIED:-
- MECHANICAL TESTING:- TENSILE, COMPRESSION SMEAR.
- EFFECT OF STRESS AND SAMPLE ORIENTATION IN RELATION TO THE WOOD GRAIN
- TEMPERATURE. 20 TO 150 DEGREES WITH PARTICULAR REFERENCE
TO THOSE AROUND THE TRANSITION TEMPERATURES OF LIGNIN (30, 60, 90, 120 & 150 DEGREES)
- ABSOLUTE MOISTURE CONTENT IN RELATION TO AMBIENT
SURROUNDINGS (SATURATED WATER VAPOUR OR HIGH PRESSURE WAFER)
- CHEMICAL TREATMENTS
THE RESULTS WILL BE PRESENTED IN TWO WAYS:
- TABLES OF RESULTS ALLOWING A QUICK COMPARISON OF THE DIFFERENT SPECIES' BEHAVIOUR UNDER VARIOUS TEST PARAMETERS
- BUILDING A MODEL ALLOWING THEORETICAL HYPOTHESES OF THE WAY IN WHICH THE MATERIAL BEHAVES UNDER VARIOUS TEST PARAMETERS
THE COMPARISON OF THE MODEL WITH THEORIES FOR THE MECHANICAL BEHAVIOUR OF ANISOTROPIC MATERIALS SHOULD INDICATE THE DIRECTION OF FURTHER WORK.
Programme(s)
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38402 Saint-Martin-d'Hères
France