Study of Fracture Properties of Composites and Aluminium Alloys Using Size Effect Method

• Main Author: Aala, Satyanarayana
• Format: Thesis
• Language: unknown
• Published: 2022
• Subjects: Structural Engineering; Construction Engineeing; Rock Mechanics; Pavement Engineering; Arctic
• Online Access: http://ethesis.nitrkl.ac.in/10347/; http://ethesis.nitrkl.ac.in/10347/1/2022_PhD_ASatyanarayana_516CE1004_Study.pdf

The size effect is a problem of scaling, which is central to every physical theory. In fluid mechanics research, the problem of scaling continuously played a prominent role for over a hundred years. In solid mechanics research, though, the attention to scaling had many interruptions and became intense only during the last decade. The question of size effect recently became a crucial consideration in the efforts to use advanced fiber composites and sandwiches for large ship hulls, bulkheads, decks, stacks and masts, as well as for large load-bearing fuselage panels. The scaling problems are even greater in geotechnical engineering, arctic engineering, and geomechanics. In analyzing the safety of an excavation wall or a tunnel, the risk of a mountain slide, the risk of slip of a fault in the earth crust or the force exerted on an oil platform in the Arctic by a moving mile-size ice floe, the scale jump from the laboratory spans many orders of magnitude. In the present investigation, tested 186 specimens made of glass fibre composites with three different widths 30 mm, 40 mm and 50 mm, these composite specimens were tested at four different displacement loading rates to know the effect of displacement loading rate on fracture parameters by using size effect method. The fracture parameters of three different alloys 5052 – H32, 6061 – T6 and 8011 at constant strain rate were determined by using size effect method. The fracture properties of composites and aluminium alloys determined by using linear regression analyis, R-curve approach and work of fracture methods. Size-effect method is used in determining mode-I fracture characteristics of woven fiber glass/epoxy composite laminates for varying loading rates. Tensile testing of geometrically similar single edge notch (SEN) specimens with three widths 30 mm, 40 mm, and 50 mm is carried out for four different displacement loading rates, namely 1, 10, 100, and 500 mm/min. For each width (D) and loading rate, the crack-length (a) is varied as 0.125D, 0.25D, 0.375D, and ...