Strength of Tubular Members Containing Holes

1994 ◽  
Vol 116 (3) ◽  
pp. 154-162 ◽  
Author(s):  
T. M. Hsu
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Load Capacity ◽  
Compressive Load ◽  
Nonlinear Finite Element ◽  
Load Test ◽  
Small Scale ◽  
Hole Size ◽  
Compression Tests ◽  
Compression Load

A small-scale, compressive-load test program was conducted at Chevron to determine the strength of tubular members with 1 to 3 holes. The parameters evaluated include the hole size, hole shape, hole location, and number of holes. Results from these tests provide a basis for platform ultimate strength calculations that are needed in making decisions on platform repairs. More than 50 specimens were tested in air under displacment control. Test specimen lengths were limited by the test apparatus to 45 in. (1,143 mm). Tubulars used in the test had an outside diameter of 3.5 in. (89 mm), which gave member slenderness ratios of about 40. The tests were needed because of the lack of relevant compression tests on members with holes. Based on test results, there appears to be a limiting value of hole size below which the compression-load capacity of the member is practically not affected by the existence of the hole. For example, a hole that is 10 percent of the member diameter does not significantly reduce member strength. This means remedial treatment is not necessary for many small holes, when ultimate strength is the controlling consideration. Nonlinear finite element shell analyses using both ADINA and FACTS computer programs and a simplified analysis using DENTA-II PC program were performed and results compared with data. We found that nonlinear finite element programs provide good predictions of capacities of members with holes, and that a simplified DENTA-II program provides adequate and efficient predictions.

Ultimate strength of three reinforced concrete highway bridges

1985 ◽  
Vol 12 (1) ◽  
pp. 63-72 ◽  
Author(s):  
I. G. Buckle ◽  
A. R. Dickson ◽  
M. H. Phillips
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Ultimate Load ◽  
Load Capacity ◽  
Highway Bridges ◽  
Nonlinear Finite Element ◽  
Membrane Action ◽  
Element Analysis ◽  
Compressive Membrane Action

The destructive testing of three reinforced concrete highway bridges, recently made redundant by road realignment, is summarized. The procedure used to test the bridges to ultimate conditions is described and load capacities of about 20 times class 1 axle loads are reported for all structures. Analyses based on conventional ultimate strength theory can account for only two-thirds of these ultimate loads and then only if second order effects are included. A nonlinear finite element computer program has been developed and used to analyze one of these structures. Excellent prediction of the ultimate load is made by the program. It is therefore suggested that compressive membrane action, which is automatically modelled in the finite element solution, plays a significant role in the enhancement of load capacity.The paper concludes that a more sophisticated approach to the assessment of bridge load capacity is necessary if realistic estimates of actual strength are to be made. Limited experience with a nonlinear finite element program suggests one such approach. If used with care, some relief to the bridge replacement program can be expected. Key words: highway bridges, ultimate load capacity, finite element analysis, reinforced concrete, field testing, compressive membrane action.

scholarly journals Free Vibration Exploration of Rotating FGM Porosity Beams under Axial Load considering the Initial Geometrical Imperfection

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Nguyen Thi Giang
Keyword(s):  
Finite Element ◽  
Compressive Load ◽  
Shear Deformation Theory ◽  
Parameter Study ◽  
Compression Load ◽  
Large Structures ◽  
Geometrical Imperfection ◽  
Compressive Loads ◽  
Vibration Responses ◽  
Sine Functions

In practice, some components in large structures such as the connecting rods between the rotating parts in the engines, turbines, and so on, can model as beam structures rotating around the fixed axis and subject to the axial compression load; therefore, the study of mechanical behavior to these structures has a significant meaning in practice. This paper analyzes the vibration responses of rotating FGM beams subjected to axial compressive loads, in which the beam is resting on the two-parameter elastic foundation, taking into account the initial geometrical imperfection. Finite element formulations are established by using the new shear deformation theory type of hyperbolic sine functions and the finite element method. The materials are assumed to be varied smoothly in the thickness direction of the beam based on the power-law function with the porosity. Verification problems are conducted to evaluate the accuracy of the theory, proposed mechanical structures, and the calculation programs coded in the MATLAB environment. Then, a parameter study is carried to explore the effects of geometrical and material properties on the vibration behavior of FGM beams, especially the influences of the rotational speed and axial compressive load.

PHOTOGRAMMETRY MEASUREMENTS OF INITIAL IMPERFECTIONS FOR THE ULTIMATE STRENGTH ASSESSMENT OF PLATES

2021 ◽  
Vol 156 (A4) ◽  
Author(s):  
A Cubells ◽  
Y Garbatov ◽  
C Guedes Soares
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Compressive Load ◽  
Initial Imperfection ◽  
Maximum Load ◽  
Surface Shape ◽  
Element Analysis ◽  
Strength Assessment ◽  
Load Carrying ◽  
Geometrical Imperfections

The objective of the present study is to develop a new approach to model the initial geometrical imperfections of ship plates by using Photogrammetry. Based on images, Photogrammetry is able to take measurements of the distortions of plates and to catch the dominant surface shape, including the deformations of the edges. Having this data, it is possible to generate faithful models of plate surface based on third order polynomial functions. Finally, the maximum load- carrying capacity of the plates is analysed by performing a nonlinear finite element analysis using a commercial finite element code. Three un-stiffened and four stiffened plates have been modelled and analysed. For each plate, two initial imperfection models have been generated one, based on photogrammetric measurements and the other, based on the trigonometric Fourier functions. Both models are subjected to the same uniaxial compressive load and boundary conditions in order to study the ultimate strength.

REINFORCEMENT OF AGEING SHIP STRUCTURES

2021 ◽  
Vol 160 (A3) ◽  
Author(s):  
D Chichì ◽  
Y Garbatov
Keyword(s):  
Monte Carlo Simulation ◽  
Finite Element ◽  
Ultimate Strength ◽  
Steel Plate ◽  
Plate Thickness ◽  
Compressive Load ◽  
Finite Element Models ◽  
Uniform Corrosion ◽  
Finite Element Analyses ◽  
Longitudinal Stiffeners

The objective of the present study is to investigate the possibility to recover the ultimate strength of a rectangular steel plate with a manhole shape opening subjected to a uniaxial compressive load and non-uniform corrosion degradation reinforced by additional stiffeners. Finite element analyses have been carried out to verify the possible design solutions. A total of four finite element models are generated, including 63 sub-structured models. The non-uniform corrosion has been generated by the Monte Carlo simulation. The reinforcement process covers three scenarios that include mounting of two longitudinal stiffeners, two longitudinal and two transverse stiffeners and the flange on the opening. The positioning of the stiffeners has also been studied. A total of 10 cases has been selected and tested for the numerical experiment. Three different assessments have been performed to evaluate the ultimate strength, weight and cost. Two additional studies on the effect of the plate thickness and slenderness have been also carried out.

PVCO Pipeline Performance Under Large Ground Deformation

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Brad P. Wham ◽  
Christina Argyrou ◽  
Thomas D. O'Rourke ◽  
Harry E. Stewart ◽  
Timothy K. Bond
Keyword(s):  
Polyvinyl Chloride ◽  
Large Scale ◽  
Ground Deformation ◽  
Load Capacity ◽  
Compressive Load ◽  
Soil Liquefaction ◽  
Compression Tests ◽  
Cross Sectional ◽  
Joint Rotation ◽  
Statistical Characterization

Technological advances have improved pipeline capacity to accommodate large ground deformation associated with earthquakes, floods, landslides, tunneling, deep excavations, mining, and subsidence. The fabrication of polyvinyl chloride (PVC) piping, for example, can be modified by expanding PVC pipe stock to approximately twice its original diameter, thus causing PVC molecular chains to realign in the circumferential direction. This process yields biaxially oriented polyvinyl chloride (PVCO) pipe with increased circumferential strength, reduced pipe wall thickness, and enhanced cross-sectional flexibility. This paper reports on experiments performed at the Cornell University Large-Scale Lifelines Testing Facility characterizing PVCO pipeline performance in response to large ground deformation. The evaluation was performed on 150-mm (6-in.)-diameter PVCO pipelines with bell-and-spigot joints. The testing procedure included determination of fundamental PVCO material properties, axial joint tension and compression tests, four-point bending tests, and a full-scale fault rupture simulation. The test results show that the performance of segmental PVCO pipelines under large ground deformation is strongly influenced by the axial pullout and compressive load capacity of the joints, as well as their ability to accommodate deflection and joint rotation. The PVCO pipeline performance is quantified in terms of its capacity to accommodate horizontal ground strain, and compared with a statistical characterization of lateral ground strains caused by soil liquefaction during the Canterbury earthquake sequence in New Zealand.

Research on Load Bearing Behavior of Ship Stiffened Plates under Cyclic Loads

2014 ◽  
Vol 904 ◽  
pp. 446-449
Author(s):  
Hu Wei Cui ◽  
Ping Yang ◽  
Can Shen ◽  
Liang Zhou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Ultimate Strength ◽  
Nonlinear Finite Element ◽  
Stiffened Plates ◽  
Cyclic Loads ◽  
Nonlinear Finite Element Method ◽  
Load Bearing ◽  
Different Dimensions ◽  
Bearing Behavior

This paper adopts nonlinear finite element method to study the load bearing behavior of ship stiffened plates with different dimensions. The research focuses on the compressive ultimate strength, axial rigidity, and residual plastic deflection of the stiffened plates under cyclic compressive and tensile loads. The results indicate that the compressive ultimate strength and axial rigidity of stiffened plates decrease with the incremental cyclic loads significantly, meanwhile, the residual plastic deflection increases with the cyclic loads.

Strength Analyses of Sandwich Pipes for Ultra Deepwaters

2004 ◽  
Vol 72 (4) ◽  
pp. 599-608 ◽  
Author(s):  
Segen Farid Estefen ◽  
Theodoro Antoun Netto ◽  
Ilson Paranhos Pasqualino
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Thermal Insulation ◽  
Research Work ◽  
Element Model ◽  
Material Behavior ◽  
Core Material ◽  
Small Scale ◽  
Mechanical Resistance

Design requirements for pipelines regarding both ultimate strength and flow assurance in ultra deepwater scenarios motivated the development of a new sandwich pipe which is able to combine high structural and thermal insulation properties. In this concept, the annulus is filled with low cost materials with adequate thermal insulation properties and good mechanical resistance. The aim of this research work is to perform small-scale laboratorial tests and to develop a finite element model to evaluate the structural performance of such sandwich pipes with two different options of core material. After calibrated in view of the experimental results, a three-dimensional finite element model incorporating nonlinear geometric and material behavior is employed to perform strength analyses of sandwich pipes under combined external pressure and longitudinal bending. Ultimate strength envelopes for sandwich pipes are compared with those generated for single-wall steel pipes with equivalent collapse pressures. The study shows that sandwich pipe systems with either cement or polypropylene cores are feasible options for ultra deepwater applications.

Ultimate Strength Assessment of Semi-Submersible Platform Under Different Load Conditions

2017 ◽  
Author(s):  
Yangzhe Yu ◽  
Guoqing Feng ◽  
Huilong Ren
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
High Stress ◽  
Initial Imperfection ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Main Bearing ◽  
Strength Assessment ◽  
Hull Structure ◽  
Load Conditions

The nonlinear finite-element method has been widely used in evaluating the ultimate strength of stiffened plates and part of hull girders, considering the effect of boundary conditions, geometrical initial imperfection and welding-induced residual stress in recent years. However, available research on the ultimate strength of large-sized structures, especially of semi-submersible platform is limited. New large-sized semi-submersible platform has been designed with lateral brace structure and square cross-section columns. The investigation of ultimate strength of the whole structure is of paramount importance in assessing the safety and design of such large structure. Therefore, in this paper, a three-dimensional nonlinear finite element model was developed to investigate the ultimate strength of a new generation of semi-submersible platform under different load conditions and its behavior after collapse using explicit dynamic solvers. Results showed that the time dependent dynamic explicit method was reliable and feasible for the calculation of ultimate strength of such complicated structure. For the target platform, the bracings and upper hull structure were the main bearing component and were critical for the ultimate strength of the whole structure. High stress occurred in connection areas and special attention shall be paid for.

Residual Ultimate Strength of Steel Plates with Longitudinal Crack and Pitting Corrosion under Axial compression: Nonlinear Finite Element Method Investigations

2020 ◽  
pp. 1-12
Author(s):  
Farzaneh Ahmadi ◽  
Ahmad Rahbar Ranji
Keyword(s):  
Finite Element ◽  
Crack Length ◽  
Ultimate Strength ◽  
Failure Modes ◽  
Great Influence ◽  
Longitudinal Crack ◽  
Nonlinear Finite Element ◽  
Geometrical Parameters ◽  
Rectangular Plates ◽  
Element Analysis

The main aim of present study was to determine the ultimate strength of cracked and corroded plates under uniform in-plane compression. Corrosion is considered as pitting-type corrosion at one side of the plate with a central longitudinal crack. Nonlinear finite element analysis using commercial computer code, ANSYS, is used to determine the ultimate strength of deteriorated plates. Different geometrical parameters, including the aspect ratio (AR) and thickness of the plate, number of pits, pit depth-to-thickness ratio, and crack length, are considered. It is found that the AR of plates have great influence on the ultimate strength of cracked-pitted plates. Because of the position and orientation of the crack, the length of central longitudinal crack has no influence on ultimate strength reduction of cracked and cracked-pitted plates. The results show that regardless of the number of pits and crack length, in thin plates where buckling controls failure modes at ultimate strength, the number of pits has less influence on reduction of the ultimate strength than thick plates where yielding controls failure mode. Also it is concluded that in rectangular plates, arrangements of pits has more effect on reduction of the ultimate strength of cracked-pitted plates than the number of pits.

PVCO Pipeline Performance Under Large Ground Deformation

2015 ◽  
Author(s):  
Brad P. Wham ◽  
Christina Argyrou ◽  
Thomas D. O’Rourke ◽  
Harry E. Stewart ◽  
Timothy K. Bond
Keyword(s):  
Polyvinyl Chloride ◽  
Large Scale ◽  
Ground Deformation ◽  
Load Capacity ◽  
Compressive Load ◽  
Soil Liquefaction ◽  
Compression Tests ◽  
Cross Sectional ◽  
Joint Rotation ◽  
Statistical Characterization

Technological advances have improved pipeline capacity to accommodate large ground deformation associated with earthquakes, floods, landslides, tunneling, deep excavations, mining, and subsidence. The fabrication of polyvinyl chloride (PVC) piping, for example, can be modified by expanding PVC pipe stock to approximately twice its original diameter, thus causing PVC molecular chains to realign in the circumferential direction. This process yields biaxially oriented polyvinyl chloride (PVCO) pipe with increased circumferential strength, reduced pipe wall thickness, and enhanced cross-sectional flexibility. This paper reports on experiments performed at the Cornell University Large-Scale Lifelines Testing Facility characterizing PVCO pipeline performance in response to large ground deformation. The evaluation was performed on 150-mm (6-in.)-diameter PVCO pipelines with bell-and-spigot joints. The testing procedure included determination of fundamental PVCO material properties, axial joint tension and compression tests, four-point bending tests, and a full-scale fault rupture simulation. The test results show the performance of segmental PVCO pipelines under large ground deformation is strongly influenced by the axial pullout and compressive load capacity of the joints, as well as their ability to accommodate deflection and joint rotation. The PVCO pipeline performance is quantified in terms of its capacity to accommodate horizontal ground strain, and compared with a statistical characterization of lateral ground strains caused by soil liquefaction during the Canterbury earthquake sequence in New Zealand.

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