Practical stress analysis part3
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Transcript of Practical stress analysis part3
Nov 2016
The finite element method (FEM) is a numerical technique for finding approximate solutions for strain and stress of the structure stress analysis
FEM advantages:
Accurate representation of complex geometryInclusion of dissimilar material propertiesEasy representation of the total solutionCapture of local effects.
FEM is best understood from its practical application, known as finite element analysis (FEA). FEA as applied in engineering is a computational tool for performing engineering analysis
Stress Analysis
• Do we still need Experiments and sensors
• History of design by experiments
• The role of experiments in Stress Analysis with respect to the Computational Methods
• Classification of the experimental methods
Nov 2016
Stress Analysis
EXPERIMENTAL ANALYSIS OFHIGH CYCLE FATIGUE IN MACHINE ELEMENTS
Full logaritmic coordinatesFor steels three fields are discriminated:• low cycle fatigue N <105• finite life 105 < N < 2x 106• infinite life (fatigue limit) N >2x106
Nov 2016
Stress Analysis
Strain gauge• SOME WORDS ABOUT THE STORY OF STRAIN GAGE.• WHY USED A STRAIN GAGE METHOD?• THE BASICS OF STRAIN GAGE.• STRAIN GAGE MEASUREMENT.• DIFFERENT CASES OF USE OF S.G
Nov 2016
Stress Analysis
• DIFFERENT CASES OF USE OF S.G
• STRAIN GAGE MEASUREMENT.
Nov 2016
Stress Analysis
PHOTOELASTICITYPolarized lightWhen light vectors are constrained to vibrate in a systematic manner in planes normal to the direction of propagation, the beam is polarized.When the vector vibrates with constant orientation the beam is plane polarized. If the vector amplitude remains constant while the orientation changes so that the tip of the vector describes a circle the light is circularly polarized.
Nov 2016
Stress Analysis
Numerical Analysis and DesignCAD /CAM /CAE systems CATIAPRO ENGINEERUNIGRAPHICS IDEASSOLID EDGE SOLID WORKAUTOCAD MECHANICAL ...............
Stress analysis FEM software ANSYSNASTRANCOSMOS GIFTSSAP others
Nov 2016
Stress Analysis
Nov 2016
combination of methods
In general the assessing structural parts of buildings , vechiles, aircraft, etc., is based on strength calculations.This method is satisfactory if the component load and boundary conditions is defined or can be approximated. Modern design strategies demand saving in material , as a cost viewpoint or light weight design requirements.Therefore We need to do experiments even we have an advanced numerical tools to reduce the failure.
There are many experimental methods for example strain gauge , photoelasticity , ESPI.
The combination of FEM and experiments are the standard methodology for complex structure
Stress Analysis