Effect of Grain Size on the Internal Fracturing of Polycrystalline Ice

Effect of Grain Size on the Internal Fracturing of Polycrystalline Ice
Author: David M. Cole
Publisher:
Total Pages: 92
Release: 1986
Genre: Acoustic emission
ISBN:

This work presents the results of a study to examine the effects of grain size of internal microfractures in polycrystalline ice. Laboratory-prepared specimens were tested under uniaxial, constant-load creep conditions at -5 C. Grain size ranged from 1.5 to 6.0 mm. This range of grain size, under an initial creep stress of 2.0 MPa, led to a significant change in the character of deformation. The finest-grained material displayed no internal cracking and typically experienced strains of 10 to the minus 2nd power at the minimum creep rate epsilon. The coarse-grained material experienced severe cracking and a drop in the strain at epsilon min to approximately 4x10 to the minus 3rd power. Extensive post-test optical analysis allowed estimation of the size distribution and number of microcracks in the tested material. These data led to the development of a relationship between the average crack size and the average grain size. Additionally, the crack size distribution, when normalized to the grain diameter, was very similar for all specimens tested. The results indicate that the average crack size is approximately one-half the average grain diameter over the stated grain size range. A dislocation pileup model is found to adequately predict the onset of internal cracking. The work employed acoustic emission techniques to monitor the fracturing rate occurred. Other topics covered in this report include creep behavior, crack healing, the effect of stress level on fracture size and the orientation of cracked grains. Theoretical aspects of the grain size effect on material behavior are also given.

Proceedings of the Fourth International Offshore Mechanics and Arctic Engineering Symposium

Proceedings of the Fourth International Offshore Mechanics and Arctic Engineering Symposium
Author: Jin S. Chung
Publisher:
Total Pages: 640
Release: 1985
Genre: Arctic regions
ISBN:

170 papers from 20 countries under the headings: Deepwater structures; Advances in offshore structure construction techniques and operations; Wave-structure-soil interactions; Fatigue and structural mechanics; Offshore loading and control; Riser mechanics and mooring systems; Submarine pipelines; Ocean energy.

Trends in the Analysis and Design of Marine Structures

Trends in the Analysis and Design of Marine Structures
Author: Carlos Guedes Soares
Publisher: CRC Press
Total Pages: 652
Release: 2019-04-15
Genre: Technology & Engineering
ISBN: 1000024369

Trends in the Analysis and Design of Marine Structures is a collection of the papers presented at MARSTRUCT 2019, the 7th International Conference on Marine Structures held in Dubrovnik, Croatia, 6-8 May 2019. The MARSTRUCT series of Conferences started in Glasgow, UK in 2007, the second event of the series having taken place in Lisbon, Portugal in March 2009, the third in Hamburg, Germany in March 2011, the fourth in Espoo, Finland in March 2013, the fifth in Southampton, UK in March 2015, and the sixth in Lisbon, Portugal in May 2017. This Conference series specialises in dealing with Ships and Offshore Structures, addressing topics in the fields of: - Methods and Tools for Loads and Load Effects - Methods and Tools for Strength Assessment - Experimental Analysis of Structures - Materials and Fabrication of Structures - Methods and Tools for Structural Design and Optimisation - Structural Reliability, Safety and Environmental Protection. Trends in the Analysis and Design of Marine Structures is an essential document for academics, engineers and all professionals involved in the area of analysis and design of Ships and Offshore Structures. About the series: The ‘Proceedings in Marine Technology and Ocean Engineering’ series is devoted to the publication of proceedings of peer-reviewed international conferences dealing with various aspects of ‘Marine Technology and Ocean Engineering’. The Series includes the proceedings of the following conferences: the International Maritime Association of the Mediterranean (IMAM) conferences, the Marine Structures (MARSTRUCT) conferences, the Renewable Energies Offshore (RENEW) conferences and the Maritime Technology (MARTECH) conferences. The ‘Marine Technology and Ocean Engineering’ series is also open to new conferences that cover topics on the sustainable exploration and exploitation of marine resources in various fields, such as maritime transport and ports, usage of the ocean including coastal areas, nautical activities, the exploration and exploitation of mineral resources, the protection of the marine environment and its resources, and risk analysis, safety and reliability. The aim of the series is to stimulate advanced education and training through the wide dissemination of the results of scientific research.