Course ILTOF04 - Numerical, statistical and experimental aspects of fracture mechanics - formerly Miscellanea
Course ILTOF04 - Numerical, statistical and experimental aspects of fracture mechanics - formerly “Miscellanea"
Lecturer: Dr. Ing. Marco PAGGI
Lecturer: Dr. Ing. Simone PUZZI
Important: how to access the online lectures
Topic 1: Numerical methods for linear elastic fracture mechanics: modelling of stress-singularities and examples of crack propagation. (Marco PAGGI, 2 h)
Overview of numerical methods for modelling stress-singularities in linear elastic fracture mechanics: singular finite elements; enriched finite elements and hpfinite elements. Numerical computation of stress-intensity factors and shape functions using the displacement correlation technique. Presentation of Mode I and Mixed Mode crack propagation criteria, followed by numerical examples regarding Mode I and Mixed Mode crack propagation problems.
Topic 2: Experimental determination of fracture mechanics parameters for ductile and quasi-brittle materials. (Marco PAGGI, 2 h)
Experimental evaluation of the critical stress-intensity factor, KIC, for ductile materials, according to the ASTM E399 standard. Experimental evaluation of the fracture energy, GIC, for mortar and plane concrete, according to the RILEM TC-50 technical recommendation.
Topic 3: Weibull theory and probability approaches to material strength. (Simone PUZZI, 2 h)
The main features and hypotheses of the probability approaches to material strength are introduced. The main statistical fundamentals are also briefly revisited. Presented concepts include Weibull theory and its applications, namely the Weibull plot and the safety factor.
Topic 4: Size-scale effects on tensile strength: statistical distribution of defects. (Simone PUZZI, 2 h)
The size-scale effect on tensile strength predicted by Weibull theory is elucidated. Then, the expected scaling in the case of a body containing different types of defects, such as cracks, re-entrant corners and voids, loaded both in Mode I and in Mixed Mode, is also presented. The effect of material nonlinearity on scaling completes the lecture.