Local stress analysis of blunt V-notches using the digital gradient sensing method

Area of Science:

• Mechanical Engineering
• Materials Science
• Solid Mechanics

Background:

• Stress analysis at V-notch tips is crucial for material failure prediction.
• Traditional methods may face challenges with complex geometries like blunt V-notches.
• Digital Gradient Sensing (DGS) offers a potential optical approach for local stress evaluation.

Purpose of the Study:

• To extend the Digital Gradient Sensing (DGS) method for analyzing local stress fields at blunt V-notch tips.
• To develop analytical expressions for light beam deflections and evaluate stress components.
• To determine the generalized notch stress intensity factor (NSIF) for polymer materials.

Main Methods:

• Analytical derivation of angular deflections based on Filippi's stress equation.
• Theoretical plotting of angular deflection patterns under plane stress conditions.
• Experimental measurement of angular deflection contours using DGS for NSIF evaluation.

Main Results:

• Analytical expressions for angular deflections near blunt V-notch tips were derived.
• The influence of notch angle and radius on stress distribution was investigated.
• NSIF values were successfully extracted from DGS measurements in polymer samples.

Conclusions:

• The extended DGS method provides an effective and accurate means to determine local stress fields and NSIF at blunt V-notch tips.
• Experimental results showed good agreement with finite element simulations, validating the DGS approach.
• This method is valuable for characterizing stress concentrations in polymer materials with V-notch defects.