Ice Sheet Indentation Resistance in the Creep Domain

1986 ◽  
Vol 108 (1) ◽  
pp. 25-28
Author(s):  
B. Ladanyi
Keyword(s):  
Failure Modes ◽  
Wide Spectrum ◽  
Ice Sheet ◽  
Offshore Structure ◽  
Plastic Type ◽  
Out Of Plane ◽  
Creep Deformations ◽  
Limiting Case

The force exerted by a moving ice sheet on an offshore structure is known to vary strongly with the geometrical conditions at the contact with the structure and with the rate of ice movement, resulting in a wide spectrum of failure modes including both in-plane and out-of-plane failures of either brittle or plastic type. In this paper attention is concentrated to only one limiting case, in which the ice sheet moves so slowly that no fracture occurs at the contact with the structure, but the ice undergoes only in-plane creep deformations.

scholarly journals In-Plane and Out-of Plane Failure of an Ice Sheet using Peridynamics

2020 ◽  
Vol 36 (2) ◽  
pp. 265-271 ◽  
Author(s):  
Bozo Vazic ◽  
Erkan Oterkus ◽  
Selda Oterkus
Keyword(s):  
Failure Modes ◽  
Ice Sheet ◽  
Offshore Structures ◽  
Mindlin Plate ◽  
Plane Case ◽  
Plane Failure ◽  
Structure Interaction ◽  
Winkler Elastic Foundation ◽  
Peridynamic Model ◽  
Out Of Plane

ABSTRACTWhen dealing with ice structure interaction modeling, such as designs for offshore structures/icebreakers or predicting ice cover’s bearing capacity for transportation, it is essential to determine the most important failure modes of ice. Structural properties, ice material properties, ice-structure interaction processes, and ice sheet geometries have significant effect on failure modes. In this paper two most frequently observed failure modes are studied; splitting failure mode for in-plane failure of finite ice sheet and out-of-plane failure of semi-infinite ice sheet. Peridynamic theory was used to determine the load necessary for inplane failure of a finite ice sheet. Moreover, the relationship between radial crack initiation load and measured out-of-plane failure load for a semi-infinite ice sheet is established. To achieve this, two peridynamic models are developed. First model is a 2 dimensional bond based peridynamic model of a plate with initial crack used for the in-plane case. Second model is based on a Mindlin plate resting on a Winkler elastic foundation formulation for out-of-plane case. Numerical results obtained using peridynamics are compared against experimental results and a good agreement between the two approaches is obtained confirming capability of peridynamics for predicting in-plane and out-of-plane failure of ice sheets.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane, and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: Computational Approach

2007 ◽  
Author(s):  
Satoshi Tsunoi ◽  
Akira Mikami ◽  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Analytical Model ◽  
Failure Modes ◽  
Experimental Investigations ◽  
Seismic Load ◽  
Piping System ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Seismic Loadings ◽  
Local Wall Thinning

The authors have proposed an analytical model by which they can simulate the dynamic and failure behaviors of piping systems with local wall thinning against seismic loadings. In the previous paper [13], the authors have carried out a series of experimental investigations about dynamic and failure behaviors of the piping system with fully circumferential 50% wall thinning at an elbow or two elbows. In this paper these experiments have been simulated by using the above proposed analytical model and investigated to what extent they can catch the experimental behaviors by simulations.

Simulation of masonry out-of-plane failure modes by multi-body dynamics

2015 ◽  
Vol 44 (14) ◽  
pp. 2529-2549 ◽  
Author(s):  
Alexandre A. Costa ◽  
Andrea Penna ◽  
António Arêde ◽  
Aníbal Costa
Keyword(s):  
Failure Modes ◽  
Plane Failure ◽  
Body Dynamics ◽  
Out Of Plane ◽  
Multi Body

Robust Reliability Assessment for Offshore Minimum Structures Under Dynamic Loads

2002 ◽  
Author(s):  
Liangbin Xu ◽  
Guoming Chen
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Dynamic Models ◽  
Research Work ◽  
Reliability Assessment ◽  
Dynamic Loads ◽  
Offshore Structure ◽  
Numeric Calculation ◽  
Ice Loads ◽  
Robust Reliability

The offshore minimum structures are widely applied in the development of margin oilfield because of their simplicity in fabrication, low initial investment and fast-track schedule. However, they would suffer large dynamic response under exciting loads such as seismic and ice loads, which might lower their service safety. The paper is focused on robust reliability assessment for the offshore minimum structures under dynamic loads by considering first-exceeding failure mode, fatigue failure mode. The robust reliability of offshore structure is a measure of its resistance to the uncertainties, and it suits very much to the condition that the information and data are scarce. The multi-level fortification for ice-resistant offshore minimum structures is presented in this paper, that is, the structure should not be defective under normal ice condition, repairable under heavy ice condition and not collapse under the heaviest ice condition. A numeric calculation method of robust reliability and several robust reliability dynamic models for offshore minimum structures are put forward in this paper, in which plastic collapse, fatigue, and fracture are dealt with. The interaction between the different failure modes under these loads is also considered in the paper. Based on research work mentioned above, the comprehensive safety assessment for the offshore minimum structures would be more easily realized under dynamic loads such as ice loads, seismic loads. Finally, the example is given.

Improved Model for Ice Force on Conical Structure

2005 ◽  
Author(s):  
W. Feng ◽  
Z. M. Shi ◽  
L. M. Liu
Keyword(s):  
Ice Sheet ◽  
Bending Moment ◽  
Offshore Structures ◽  
Structure Design ◽  
Offshore Structure ◽  
Conical Structure ◽  
Offshore Structure Design ◽  
Improved Model ◽  
Ice Force ◽  
Bending Failure

Ice force is an important factor to be taken into account for offshore structures in cold region, and the calculation method of the ice force is meaningful for the offshore structure design. Cone is now used as optimal ice-resistant structure because it can cause bending failure of the ice sheet. The interaction between ice sheet and conical structure is studied in this paper and Croasdale’s model is modified based on the field observations. The newly built model separates the ice sheet into emersed part and floating part, and the equilibrium analyses are carried out respectively. The bending moment distribution of the ice sheet is analyzed to determine the position of bending failure, which serves as a supplementary restriction. Analytic solution of ice force on conical structure is got and it is verified by the experimental data of previous researches.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2007 ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending ◽  
The Difference

In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3-D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned wall elbow, because the life of piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

Building Typologies Prevalent in Northern Pakistan and Their Performance during the 2015 Hindu Kush Earthquake

2016 ◽  
Vol 32 (4) ◽  
pp. 2473-2493 ◽  
Author(s):  
Najif Ismail ◽  
Nouman Khattak
Keyword(s):  
Failure Modes ◽  
Strong Motion ◽  
Masonry Walls ◽  
Northern Pakistan ◽  
Ground Settlement ◽  
Hindu Kush ◽  
Reverse Faulting ◽  
Out Of Plane ◽  
Shear Cracking ◽  
Motion Characteristics

The M7.5 earthquake of 26 October 2015 resulted due to reverse faulting at an intermediate depth of 210 km within the northeast-trending tabular zone underneath the Hindu Kush region, with its epicenter located 45 km southwest of Jarm in Afghanistan. In Pakistan alone, the earthquake and subsequent aftershock swarm resulted in 280 fatalities, injuries to 1,770 persons, and notable damage to 109,123 buildings. A synopsis of observations is presented herein, covering details about seismotectonics, strong motion characteristics, damage statistics, and typical building failure modes. Building damage was observed to mostly concentrate in vulnerable rural and old unreinforced masonry buildings, with aspects such as complete or partial out of plane collapse of walls, collapse of roofs due to loss of seating, shear cracking in masonry walls/panels, shear and flexural damage in masonry spandrels, cracking at infill-frame interface, damage at building corners, pounding damage, toppled minarets, and damage due to ground settlement.

Comparison of Electronic Component Durability Under Uniaxial and Multiaxial Random Vibrations

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Matthew Ernst ◽  
Ed Habtour ◽  
Abhijit Dasgupta ◽  
Michael Pohland ◽  
Mark Robeson ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Failure Modes ◽  
Accumulation Rate ◽  
Center Of Mass ◽  
Dynamic Environment ◽  
Test Method ◽  
Printed Wiring Board ◽  
Uniaxial Testing ◽  
Out Of Plane ◽  
Wiring Board

Multiaxial and uniaxial vibration experiments were conducted in order to study the differences in failure modes and fatigue life for the two types of excitation. An electrodynamic (ED) shaker capable of controlled vibration in six degrees of freedom (DOF) was employed for the experiments. The test specimen consisted of six large inductors insertion mounted on a printed wiring board (PWB). Average damage accumulation rate (DAR) in the inductor leads was measured for random excitations in-plane, out-of-plane, and both directions simultaneously. Under simultaneous multiaxial excitation, the average DAR was found to be 2.2 times greater than the sum of the in-plane and out-of-plane DARs. The conclusion was that multiple-step sequential uniaxial testing may significantly overestimate the durability of large/heavy structures with high center of mass in a multiaxial dynamic environment. Additionally, a test method utilizing uniaxial vibration along a direction other than the principal directions of the structure was examined. This method was found to have significant limitations, but showed better agreement with simultaneous multiaxial vibration experiments.

Sign in / Sign up

Export Citation Format

Share Document