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.

A Three-Dimensional Model for Ice Rubble Pile-Ice Sheet-Conical Structure Interaction at the Piers of Confederation Bridge, Canada

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Chee K. Wong ◽  
Thomas G. Brown
Keyword(s):  
Three Dimensional ◽  
Ice Sheet ◽  
Offshore Structures ◽  
Flexural Behavior ◽  
Small Scale ◽  
Structure Interaction ◽  
Flexural Failure ◽  
Modes Of Failure ◽  
Conical Structure ◽  
Rubble Pile

Offshore structures constructed in waters where ice cover is prevalent for several months a year are subjected to ice loading. Some of these structures are conical or sloped-faced in shape, where flexural failure becomes the dominant mode of failure for the ice sheet. The flexural failure mode reduces the magnitude of ice-structure interaction loads in comparison to other modes of failure. Various researchers have devised flexural failure models for ice-conical structure interactions. Each model shares the same principle of the ice sheet being modeled as a beam on an elastic foundation, but each model has different limitations in precisely simulating the interaction. Some models do not incorporate the ice rubble pile, while other models make oversimplified assumptions for three-dimensional behavior. The proposed three-dimensional (3D) model aims to reduce some of these limitations with the following features: (1) modeling the geometry of the ice rubble pile around the conical pier using the results of small-scale tests, (2) modeling the loads exerted by the ice rubble pile on the conical structure and ice sheet with a rigorous method of slices, (3) adding driving forces in keeping the rubble pile intact and in upward motion during the interaction, (4) accounting for eccentric offsetting moments at the ice-structure contacts, and (5) modeling the flexural behavior of the ice sheet subject to ice rubble loads using finite element method. The proposed model is used to analyze the interaction events recorded at the conical piers of the Confederation Bridge over a period of 11 years.

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

scholarly journals Peridynamic Model for a Mindlin Plate Resting on a Winkler Elastic Foundation

2020 ◽  
Vol 2 (3) ◽  
pp. 229-242
Author(s):  
Bozo Vazic ◽  
Erkan Oterkus ◽  
Selda Oterkus
Keyword(s):  
Elastic Foundation ◽  
Fracture Behaviour ◽  
Mindlin Plate ◽  
Winkler Foundation ◽  
Transverse Loading ◽  
Dynamic Relaxation ◽  
Pure Bending ◽  
Fracture Patterns ◽  
Winkler Elastic Foundation ◽  
Peridynamic Model

AbstractIn this study, a peridynamic model is presented for a Mindlin plate resting on a Winkler elastic foundation. In order to achieve static and quasi-static loading conditions, direct solution of the peridynamic equations is utilised by directly assigning inertia terms to zero rather than using widely adapted adaptive dynamic relaxation approach. The formulation is verified by comparing against a finite element solution for transverse loading condition without considering damage and comparing against a previous study for pure bending of a Mindlin plate with a central crack made of polymethyl methacrylate material having negligibly small elastic foundation stiffness. Finally, the fracture behaviour of a pre-cracked Mindlin plate rested on a Winkler foundation subjected to transverse loading representing a floating ice floe interacting with sloping structures. Similar fracture patterns observed in field observations were successfully captured by peridynamics.

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 Environmental and Economic Impact of Retrofitting Techniques to Prevent Out-of-Plane Failure Modes of Unreinforced Masonry Buildings

2021 ◽  
Vol 13 (20) ◽  
pp. 11383
Author(s):  
Linda Giresini ◽  
Claudia Casapulla ◽  
Pietro Croce
Keyword(s):  
Environmental Impact ◽  
Failure Modes ◽  
Energy Savings ◽  
Energy Performance ◽  
Masonry Buildings ◽  
Plane Failure ◽  
Seismic Displacement ◽  
Cost Curves ◽  
Integrated Intervention ◽  
Out Of Plane

This paper presents an innovative methodology to assess the economic and environmental impact of integrated interventions, namely solutions that improve both structural and energy performance of existing masonry buildings, preventing out-of-plane modes and increasing their energy efficiency. The procedure allows the assessment of the environmental and the economic normalized costs of each integrated intervention, considering seismic and energy-saving indicators. In addition, the work introduces in relative or absolute terms two original indicators, associated with seismic displacement and thermal transmittance. The iso-cost curves so derived are thus a powerful tool to compare alternative solutions, aiming to identify the most advantageous one. In fact, iso-cost curves can be used with a twofold objective: to determine the optimal integrated intervention associated with a given economic/environmental impact, or, as an alternative, to derive the pairs of seismic and energy performance indicators associated with a given budget. The analysis of a somehow relevant case study reveals that small energy savings could imply excessive environmental impacts, disproportionally increasing the carbon footprint characterizing each intervention. Iso-cost curves in terms of absolute indicators are more suitable for assessing the effects of varying acceleration demands on a given building, while iso-cost curves in terms of relative indicators are more readable to consider a plurality of cases, located in different sites. The promising results confirm the effectiveness of the proposed method, stimulating further studies.

scholarly journals Numerical Simulation of Unreinforced Masonry Buildings with Timber Diaphragms

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 205
Author(s):  
Igor Tomić ◽  
Francesco Vanin ◽  
Ivana Božulić ◽  
Katrin Beyer
Keyword(s):  
Failure Modes ◽  
Unreinforced Masonry ◽  
Masonry Walls ◽  
Masonry Buildings ◽  
Seismic Behaviour ◽  
Plane Failure ◽  
Friction Resistance ◽  
Flexible Diaphragms ◽  
Out Of Plane ◽  
Equivalent Frame

Though flexible diaphragms play a role in the seismic behaviour of unreinforced masonry buildings, the effect of the connections between floors and walls is rarely discussed or explicitly modelled when simulating the response of such buildings. These flexible diaphragms are most commonly timber floors made of planks and beams, which are supported on recesses in the masonry walls and can slide when the friction resistance is reached. Using equivalent frame models, we capture the effects of both the diaphragm stiffness and the finite strength of wall-to-diaphragm connections on the seismic behaviour of unreinforced masonry buildings. To do this, we use a newly developed macro-element able to simulate both in-plane and out-of-plane behaviour of the masonry walls and non-linear springs to simulate wall-to-wall and wall-to-diaphragm connections. As an unretrofitted case study, we model a building on a shake table, which developed large in-plane and out-of-plane displacements. We then simulate three retrofit interventions: Retrofitted diaphragms, connections, and diaphragms and connections. We show that strengthening the diaphragm alone is ineffective when the friction capacity of the wall-to-diaphragm connection is exceeded. This also means that modelling an unstrengthened wall-to-diaphragm connection as having infinite stiffness and strength leads to unrealistic box-type behaviour. This is particularly important if the equivalent frame model should capture both global in-plane and local out-of-plane failure modes.

Numerical Prediction of Failure in Unidirectional Fiber Reinforced Composite

2021 ◽  
pp. 2150073
Author(s):  
Ignacio Valdivia ◽  
Cristian Canales ◽  
Víctor Tuninetti ◽  
Paulo Flores ◽  
Carlos Medina
Keyword(s):  
Failure Modes ◽  
Transverse Isotropy ◽  
Failure Criteria ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Plane Failure ◽  
Fiber Reinforced Composite ◽  
Unidirectional Fiber ◽  
Reinforced Composite ◽  
Out Of Plane

Fiber-reinforced polymer composites exhibit orthotropic mechanical properties and particularly low strength in the out-of-plane direction. The use of classical failure criteria that consider transverse isotropy to evaluate these composite materials implies an overestimation of their out-of-plane strength, which could lead to a nonconservative and even catastrophic design. The Molker failure criteria developed for orthotropic materials consider the LaRC05 failure modes as a basis, with two additional failure modes for the out-of-plane direction of noncrimp fiber (NCF)-reinforced composites. Given the similarity in configuration and orthotropic behavior of unidirectional fiber fabric reinforced composites to NCF-reinforced composites, Molker failure criteria are implemented and applied in this research to determine the initiation of out-of-plane failure in unidirectional fiberglass fabric composites. The criteria are programmed in the form of a module coupled to a constitutive model available in a finite element method (FEM) package. Then, the mechanical properties and failure parameters of the unidirectional fiber-reinforced composite are determined. Model validation is accomplished by comparing numerical and experimental results of out-of-plane failure in a corrugated panel. In addition, several failure criteria used in unidirectional fiber-reinforced composite that consider transverse isotropy are evaluated. The results of critical load at the onset of transverse out-of-plane failure obtained by using the Molkerorthotropic criterion prove to be superior in accuracy compared to those obtained with the criteria commonly applied to this type of materials.

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.

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