Collapse Behavior of Tensegrity Barrel-Vault Structures Based on Di-Pyramid (DP) Units

2020 ◽  
Vol 20 (11) ◽  
pp. 2050119
Author(s):  
K. Mirzaaghazadeh ◽  
K. Abedi ◽  
B. Shekastehband
Keyword(s):  
Lateral Thrust ◽  
Initial Stiffness ◽  
Collapse Strength ◽  
Asymmetric Loading ◽  
Collapse Resistance ◽  
Symmetric Loading ◽  
Type Boundary ◽  
Collapse Behavior ◽  
Type Constraint ◽  
Loading Type

In this study, the collapse behavior of a family of tensegrity structures, i.e. di-pyramid (DP) barrel-vaults that can offer promising solutions for civil engineering applications is analyzed. Depending on whether struts’ snap or cables’ rupture dictate the occurrence of overall collapse, two different designs are considered. The effects of geometric parameters, self-stress properties, loading type, boundary conditions and strengthening schemes on the structural behavior are discussed. It is found that the structures with symmetric and ridge loading types undergo bifurcation type instability instead of limit point which is encountered in the cases with asymmetric loading type. Constraint against lateral thrust is beneficial in improving strength and initial stiffness of the studied cases, by as much as 60% and 90%, respectively. In most cases, the rate of strength variation associated with increasing self-stress levels is quite slow, while the slackness load increases by at least 400% being the primary achievements. By using non-uniform self-stress distribution, the initial stiffness of these structures can be increased up to 240%. Increasing the rise-to-span ratio improves the initial stiffness and collapse strength of the structure significantly at the expense of expedition of cables slackness. Significant gains in collapse resistance of these structures under symmetric loading are obtained with strengthened critical struts or cables, depending on which collapse case dominates, but the initial stiffness is generally not influenced by these schemes.

Experimental Study on the Collapse Strength of Narrow Stiffened Panels

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Ming Cai Xu ◽  
C. Guedes Soares
Keyword(s):  
Carrying Capacity ◽  
Longitudinal Direction ◽  
Strain Gauges ◽  
Load Carrying Capacity ◽  
Stiffened Panels ◽  
Modes Of Failure ◽  
Collapse Strength ◽  
Tension Tests ◽  
Load Carrying ◽  
Collapse Behavior

The results of five tests on narrow stiffened panels under axial compression until collapse and beyond are presented to investigate the collapse behaviors of stiffened panels. Tension tests were used to evaluate the material properties of the stiffened panels. The tests were made on panels with two half bays plus one full bay in the longitudinal direction. Initial loading cycles were used to eliminate the residual stresses of the stiffener panels. The strain gauges were set on the plates and the stiffeners to record the strain histories. The displacement load relationship was established. The collapse behavior, modes of failure and load-carrying capacity of the stiffened panels are investigated with the experiment.

Mechanical Behaviour of Three Dimensional Lattice Structures

2011 ◽  
Vol 462-463 ◽  
pp. 1302-1307
Author(s):  
Kuniharu Ushijima ◽  
Dai Heng Chen ◽  
Wesley J. Cantwell
Keyword(s):  
Mechanical Behaviour ◽  
Lattice Structure ◽  
Compressive Loading ◽  
Three Dimensional ◽  
Beam Theory ◽  
Lattice Structures ◽  
Initial Stiffness ◽  
Dimensional Lattice ◽  
Collapse Strength ◽  
The One

In this study, a theoretical analysis for predicting the mechanical properties of three dimensional lattice structures under compressive loading is proposed, and verified by comparing the analytical predictions with FEM results. This theory for estimating the initial stiffness E* is based on the classical beam theory, and the one for estimating the plastic collapse strength reflects the stress state for each lattice structure. In particular, effects of inner geometry (strand’s diameter-to-length ratio and micro-architecture) on the mechanical behaviour are discussed.

Deep Water Carcass Development: Effects of Carcass Profile on Collapse Resistance

2013 ◽  
Author(s):  
Jian Zhao ◽  
Zhimin Tan ◽  
Terry Sheldrake
Keyword(s):  
Hydrostatic Pressure ◽  
Deep Water ◽  
Element Model ◽  
Design Parameters ◽  
External Hydrostatic Pressure ◽  
Acceptance Criterion ◽  
Collapse Strength ◽  
Collapse Resistance ◽  
Flexible Pipes ◽  
Inclination Angles

The increasing application of flexible pipes in deep water requires extension of the product’s capability through higher design pressures with large diameters, while one of the most important structural capacities is collapse resistance. In addition to the introduction of new materials and manufacturing capability, the carcass structure is also expected to be optimized for maximum purpose. The carcass is an interlocked metallic construction that is used as the innermost layer to prevent for example, either totally or partially, the collapse of the internal pressure sheath due to decompression, or the pipe, due to external hydrostatic pressure, tensile armour pressure, and mechanical crushing loads. During manufacture of the carcass, its profile may differ from the nominal designed profiles and this may affect the collapse resistance. In this paper the effects of the carcass profile on the wet collapse strength of flexible pipes via numerical simulation are investigated. The wet collapse strength is referred to as the hydrostatic collapse strength of the pipe when the annulus is assumed to be flooded with seawater. In this condition, the external hydrostatic pressure acts directly on the barrier layer above the carcass. Using ANSYS, a 3D finite element model with the consideration of helical effects and cyclic boundary condition, which was developed to check the effect of each part of the carcass profile on the collapse strength by varying the design parameters, e.g. inclination angles, etc, and manufacturing ovality. As both verification and comparison, the principle of the effects is explored and explained analytically. The results can be used as an acceptance criterion on the as-built profiles in the manufacturing process, and as a guideline for the innovation and optimization of the carcass for maximum performance.

scholarly journals Study on Progressive Collapse Behavior of SRC Column-Steel Beam Hybrid Frame Based on Pushdown Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Liusheng Chu ◽  
Gaoju Li ◽  
Danda Li ◽  
Jun Zhao
Keyword(s):  
Progressive Collapse ◽  
Bending Moment ◽  
Small Deformation ◽  
Vertical Position ◽  
Steel Beam ◽  
Practical Applications ◽  
Collapse Resistance ◽  
Beam Mechanism ◽  
Collapse Behavior ◽  
Pushdown Analysis

To investigate the progressive collapse behavior of Steel Reinforced Concrete (SRC) column-steel beam hybrid frame after the failure of key structural elements, a PQ-Fiber model for an 8-storey structure is established in ABAQUS program. Nonlinear dynamic and static pushdown analysis are carried out after the failure and removal of the bottom-middle and bottom-corner columns. Numerical results of both methods agree well with each other. Results show that SRC column-steel frame has good resistance to progressive collapse under dynamic instantaneous load. After sudden removal of a bottom middle column, the development of structural collapse exhibits two mechanisms, the beam mechanism and the catenary mechanism. When the structure is within small deformation range, the collapse resistance of the residual frame is provided by the beam bending moment capacity, which is beam mechanism. For large deformation situation, the collapse resistance is mainly provided by the beam tensile strength, which is catenary mechanism. However, with the removal of a bottom corner column, the residual structure only undergoes the beam mechanism even for large deformations. For future practical applications, the influence of the steel ratio, steel section size, and the vertical position of the removed key components are investigated through a detailed parametric study.

Plastic Collapse Behaviors of Tubulars With Recess Patterns

2015 ◽  
Author(s):  
Haifeng Zhao ◽  
David Iblings ◽  
Aleksey Barykin ◽  
Mohamed Mehdi
Keyword(s):  
Empirical Relationship ◽  
External Pressure ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Plastic Collapse ◽  
Strength Reduction Factor ◽  
Periodic Distribution ◽  
Collapse Strength ◽  
Post Buckling ◽  
Collapse Behavior

The collapse strength of tubulars with recess patterns machined into their walls is an important topic for oilfield downhole tools as it applies to perforating guns, prepacked sand screens, and perforated and slotted liners. This paper presents a study of the plastic collapse behavior of thick-walled tubulars (those with an outside diameter to thickness ratio of approximately 10) having different patterns of circular recesses (blind holes partially machined into the tubing wall) that are subjected to external pressure. An empirical relationship between the reduction in collapse strength and the periodic distribution of recesses was constructed to account for the weakening effects of recess diameter, recess depth, axial spacing, angular phasing, etc. This strength reduction factor was introduced into the Tamano formula to predict collapse strength of recessed tubulars. Applicability of this empirical formula was validated with the aid of nonlinear, post-buckling Finite Element Analyses (FEA). The modeling approach was verified by full-scale physical tests. However, results of the physical testing are not presented in this paper. The strength reduction factor in combination with the Tamano formula provides a simple way of parametrically predicting the collapse strength of tubulars having circular recess patterns.

Enhancement of Collapse Resistance of UOE Pipe Based on Systematic Exploitation of Thermal Cycle of Coating Process

2008 ◽  
Author(s):  
Andreas Liessem ◽  
Johannes Groß-Weege ◽  
Steffen Zimmermann ◽  
Gerhard Knauf
Keyword(s):  
Plastic Deformation ◽  
Thermal Treatment ◽  
Yield Strength ◽  
Thermal Cycle ◽  
Compressive Yield Strength ◽  
Coating Process ◽  
Cold Plastic Deformation ◽  
Production Route ◽  
Collapse Strength ◽  
Collapse Resistance

The present paper discusses recent results of an ongoing study on the effect of thermal treatment on collapse strength of cold formed pipes, for instance those following the UOE production route. It has been recognized that thermal treatment as encountered during thermal cycle of pipe coating processes may compensate the reduction of compressive yield strength owing to cold plastic deformation induced during forming. This effect has been systematically analyzed. Enhancement of collapse resistance exploiting the thermal cycle of coating process was studied based on experimental evidence, Finite Element simulations as well as theoretical analysis. It is herein shown that appropriate thermal treatment manifests itself positively with respect to compressive yield strength, leading to significantly improved collapse pressures. As a result fabrication factors of one and even higher may be applicable.

Plastic Collapse Behaviors of Tubulars with Recess Patterns—Application in Hollow Carrier Perforating Guns

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Haifeng Zhao ◽  
David Iblings ◽  
Aleksey Barykin ◽  
Mohamed Mehdi
Keyword(s):  
Empirical Relationship ◽  
External Pressure ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Oil Field ◽  
Plastic Collapse ◽  
Strength Reduction Factor ◽  
Periodic Distribution ◽  
Collapse Strength ◽  
Collapse Behavior

The collapse strength of tubulars with recess patterns machined into their walls is an important topic for oil field downhole tools, especially in hollow carrier perforating gun systems. This paper presents a study of the plastic collapse behavior of thick-walled tubulars (those with an outside diameter to thickness ratio of approximately ten) having different patterns of circular recesses (blind holes partially machined into the tubing wall) that are subjected to external pressure. An empirical relationship between the reduction in collapse strength and the periodic distribution of recesses was constructed to account for the weakening effects of recess diameter, recess depth, axial spacing, angular phasing, etc. This strength reduction factor was introduced into the Tamano formula to predict collapse strength of recessed tubulars. Applicability of this empirical formula was validated with the aid of nonlinear, postbuckling finite element analyses (FEA). The strength reduction factor in combination with the Tamano formula provides a simple way of parametrically predicting the collapse strength of tubulars having circular recess patterns.

The Prediction and Enhancement of UOE-DSAW Collapse Resistance for Deepwater Linepipe

2004 ◽  
Author(s):  
Mark Fryer ◽  
Peter Tait ◽  
Stelios Kyriakides ◽  
Chris Timms ◽  
Duane DeGeer
Keyword(s):  
Oil And Gas ◽  
Processing Parameters ◽  
Pipe Production ◽  
Test Results ◽  
Enhanced Resistance ◽  
Collapse Strength ◽  
Collapse Resistance ◽  
Offshore Pipeline ◽  
Temperature Heat ◽  
Temperature Heat Treatment

With the increasing development of oil and gas reserves in water depths greater than 1500 m, linepipe used for deepwater and ultra-deepwater applications will require enhanced resistance to hydrostatic collapse. To support this need, Corus Tubes has been investigating methods by which increases in UOE linepipe collapse strength can be achieved. In particular, it has been theorised that modifications to the UOE manufacturing process can provide the necessary collapse strength enhancements. Pipe production trials were conducted focusing on the effect of processing parameters during UOE linepipe production, and in addition low temperature heat treatment was used to assess its effect. Full-scale collapse tests were then performed on the resulting linepipe specimens to validate the increase in collapse strength. The results of this work have demonstrated the beneficial effect of a modified UOE manufacturing approach on linepipe collapse resistance. This paper summarizes the work performed, quantifies the increase in collapse strength, and compares the test results to collapse equations found in offshore pipeline standards. It is also demonstrated that the UOE fabrication factor of 0.85 in the DNV offshore pipeline code (DNV OS-F101) may be considered to be over conservative, when linepipe is manufactured using the modified approach summarized herein.

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