scholarly journals Cylinders with a steel-concrete-steel wall to resist external pressure

2018 ◽  
Author(s):  
Charles Douglas Goode ◽  
Tom Nash
Keyword(s):  
Failure Load ◽  
External Pressure ◽  
Cylinder Wall ◽  
Failure Pressure ◽  
Different Depths ◽  
Composite Wall

In the 1980’s Manchester University carried out over 110 tests on cylinders with a composite wall (steel-concrete-steel) subjected to external pressure as already reported in the literature.  This paper describes further tests on 9 cylinders with a composite wall and a dome end subjected to external pressure and reports the results and compares them with theory.  The cylinders were 500 mm diameter and 1250 mm long and four of them had penetrations through the cylinder wall.  These tests were carried out under contract for Tecnomare SpA of Italy and have not been previously reported because of confidentiality reasons.  The agreement between test behaviour, failure load and the theory developed at Manchester University is good. The philosophy for the design of such vessels for seabed structures is discussed and a ‘depth margin’ method proposed as it is a more realistic way of applying safety.  Examples of designs for different depths are given and compared with the predicted failure pressure. 

Influence of Delamination on Strength of Externally Pressurized Glass/Epoxy Cylinders

1999 ◽  
Author(s):  
Peter Davies ◽  
Leif A. Carlsson
Keyword(s):  
Impact Damage ◽  
Compressive Load ◽  
External Pressure ◽  
Cylinder Wall ◽  
Failure Pressure ◽  
Filament Wound ◽  
Local Reduction ◽  
Delamination Resistance ◽  
Cylinder Strength ◽  
Winding Angle

Abstract The delamination resistance of filament wound glass/epoxy cylinders has been characterized for a range of winding angles and fracture mode ratios using beam fracture specimens. The results reveal that the fracture resistance increases with increasing winding angle and mode II (shear) fraction (GII/G). It was also found that interlaced fiber bundles in the filament wound cylinder wall acted as effective crack arresters in mode I loading. To examine the sensitivity of delamination damage on the implosion behavior of cylinders, external pressure tests were performed on filament-wound glass/epoxy composite cylinders with artificial defects and impact damage. The results revealed that the cylinder strength was insensitive to the presence of single delaminations but impact damage caused reductions in failure pressure. The insensitivity of the failure pressure to a single delamination is attributed to the absence of buckling of the delaminated sublaminates before the cylinder wall collapsed. The impacted cylinders contained multiple delaminations, which caused local reduction in the compressive load capability and reduction in failure pressure.

scholarly journals Maintenance Techniques for Cracks in Asphalt Layers

2021 ◽  
pp. 25-37
Author(s):  
M. S. Eisa ◽  
F. S. Abdelhaleem ◽  
V. A. Khater
Keyword(s):  
Failure Load ◽  
Asphalt Pavements ◽  
Water Intrusion ◽  
Small Depth ◽  
Major Stage ◽  
Maintenance Work ◽  
Different Depths ◽  
Maintenance Techniques ◽  
Pavement Structure

Treating cracks in asphalt pavements is a major stage of each maintenance work for engineers. The goal of any crack cure is to limit the water intrusion into underlying pavement structure layers. Such water infiltrates in to base layers of the pavement and may cause damage to the pavement structure. The previous studies focused on crack repairing materials and methods but not the bonding at the interface joint. In this study, the influence of the repairing materials and depth on the bonding at the interface joint using two repairing materials. Slabs were cast to simulate surface of road. Unlikely, slabs contain cracks in the middle of slab with different depths (35 mm, 50 mm, 70 mm). Consequently, these cracks were repaired with two methods; firstly, repairing them with RC+Sand and secondly, with Sika flex®-1a. The slabs were tested after being repaired to know the best method and depth. It has been concluded that slabs having cracks that have been repaired with RC+Sand increase failure load compared with empty cracks and cracks that have been repaired with Sika flex®-1a. Also, cracks with small depth that have been repaired with Sika flex®-1a increase failure load compared with empty cracks.

Detection of Mechanical Properties of Reinforced Concrete Pipes and Affected the Quality of Construction

2014 ◽  
Vol 633-634 ◽  
pp. 904-908
Author(s):  
Yan Min Yang ◽  
Run Tao Zhang ◽  
Bo Qu ◽  
Jian Ping Sun
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Quality Management ◽  
Failure Load ◽  
External Pressure ◽  
Local Deformation ◽  
Pressure Loading ◽  
Loading Test ◽  
Concrete Pipes

Through analyzing construction method specimens parameter detection and external pressure loading test,test drainage construction technical indicators reinforced concrete pipes,cracks load,failure load,local deformation and overall deformation,research and evaluation of the performance of its force drainage construction quality management.

Surface Stress Analysis of Internally Corroded Pipes Under External Pressure

2017 ◽  
Author(s):  
Zhanfeng Chen ◽  
Xiaoli Shen ◽  
Hao Ye ◽  
Sunting Yan ◽  
Zhijiang Jin
Keyword(s):  
Surface Stress ◽  
Internal Surface ◽  
Approximate Solutions ◽  
External Pressure ◽  
Diameter Ratio ◽  
Stress Distributions ◽  
Failure Pressure ◽  
Hoop Stresses ◽  
Stress Function Method ◽  
Maximum Stresses

Corrosion often leads to the failure of transporting pipelines. The surface stresses on the corroded pipes are related to the failure pressure. In this paper, a double circular arc (DCA) model is developed to calculate the surface stress of the internal corroded pipes under external pressure. In addition, a critical corrosion ratio and a critical thickness-to-diameter ratio are presented to determine the location of the maximum stress. Based on the stress function method and bipolar coordinates, an analytical solution of the DCA model was obtained. And then the stress distributions on the internal and external surfaces of the corroded pipes were determined. Next, the equivalent and hoop stresses at several locations in the cross section of the corroded pipes were discussed. The calculated results were validated using finite element method (FEM). Results show that the maximum stresses vary from the internal surface to the external surface with the increase of the corrosion ratio or the thickness-to-diameter ratio. Our research provides a benchmark for approximate solutions to predict the failure pressure and assess the integrity of the corroded pipelines.

scholarly journals Matric suction effect on distribution of stresses caused by vehicle wheels on a bare silty sand

2021 ◽  
Vol 337 ◽  
pp. 03004
Author(s):  
Juan Alfredo Torrico Bravo ◽  
Salvador Miranda ◽  
Wim Cornellis ◽  
Juan Carlos Rojas ◽  
Adam Bezuijen ◽  
...  
Keyword(s):  
Soil Profile ◽  
Cropping Systems ◽  
Soil Surface ◽  
Matric Suction ◽  
External Pressure ◽  
Silty Sand ◽  
Vehicle Loading ◽  
Load Cells ◽  
Different Depths ◽  
Bare Soils

-Soil compaction in cropping systems, caused by the external pressure of machinery, creates impermeable layers that restrict water and nutrient cycles reducing agricultural production. To evaluate the matric suction effects on distribution with depth of stresses in a soil, caused by the use of agricultural machinery, Jet Fill tensiometers were installed at two different depths (i.e. 0.15 m, 0.30 m) in a soil profile constituted by silty sand with gravel (SM); to register the increments on subsoil vertical stresses, two miniaturized load cells (i.e. 16. 5 mm in diameter) were installed in a horizontal position under the centre line of the vehicle wheels’ path, at approximately 0.15 m and 0.30 m depth. Care was taken to calibrate the load cells in field conditions. A vehicle was made to pass over the soil surface, at a speed less than 5 km/h; the tyre inflation pressure applied on wheel was 380 kPa. Response of load cells to vehicle loading was evaluated at different average matric suction measured on soil profile. Finally, measured stresses have been compared with values obtained by applying well-known elastic theoretical methods used to assess stresses applied by tyres on bare soils. The corresponding results show that the increment of vertical stresses decreases as matric suction increases, and a good correlation between measurements and simulations of the increment on subsoil vertical stress.

Experimental and numerical assessment on failure pressure of textured pipelines

2021 ◽  
pp. 1-20
Author(s):  
Hassan Karampour ◽  
Mahmoud Alrsai ◽  
Hossein Khalilpasha ◽  
Faris Albermani
Keyword(s):  
Ductile Failure ◽  
Tensile Tests ◽  
External Pressure ◽  
Burst Pressure ◽  
Failure Pressure ◽  
Numerical Assessment ◽  
Pressure Tests ◽  
Physical Tests ◽  
Smooth Pipe ◽  
Do So

Abstract A series of physical tests and finite element (FE) analyses are conducted to evaluate the failure of smooth (conventional) and textured (proposed concept) pipes. To do so, hydrostatic pressure tests are performed on aluminium beverage cans (ductile failure) and additively manufactured Ti6Al4V-0406 titanium pipes (brittle failure). Mechanical material properties are obtained from tensile tests of coupon samples. In absence of physical burst pressure tests, FE models are validated against experimental results of external pressure tests and are used to predict the buckle initiation (Pi) and burst pressure (Pb) capacity of the textured pipes with different number of circumferential triangles, N, and base angles, a. Results show that buckle initiation pressures of the textured concept is 2.34 and 1.80 times greater than those of the smooth aluminium cans and titanium pipes, respectively. However, the burst pressure of the textured pipe can only get 3% greater than the smooth pipe. Based on the current results a textured pipe with N=6 and a=30° is the optimum textured design.

Collapse of Thick Tubes Pressurized From Outside: An Accurate Predictive Formula

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Leone Corradi ◽  
Christian Ghielmetti ◽  
Lelio Luzzi
Keyword(s):  
Simple Formula ◽  
External Pressure ◽  
Large Displacement ◽  
Numerical Analyses ◽  
Preliminary Design ◽  
Relative Role ◽  
Engineering Applications ◽  
Failure Pressure ◽  
Collapse Behavior ◽  
Precise Assessment

Several engineering applications require cylindrical shells subjected to external pressure, and an increasing need for tubes of significant thickness has been experienced in recent years. So far, little study has been devoted to very stocky tubes, and a great amount of uncertainty exists on some important aspects, such as the consequences of imperfections on their failure pressure. This can only be computed by performing numerical analyses that consider both material (plasticity) and geometric (large displacement) nonlinearities. Such a procedure is feasible, but its use for design purposes is cumbersome, and handy alternatives are worth searching. In this paper, a comparatively simple formula is proposed, based on an interpretation of the relative role that plasticity and instability play in the thick tube range. The formula depends on a crucial coefficient, which can be defined so as to provide safe but reasonably accurate approximations to the collapse pressures computed numerically for tubes made of different metals. The proposal may be useful for preliminary design purposes and can be considered as a first contribution toward a precise assessment of the collapse behavior of tubes in a thickness range so far overlooked.

Plastic Buckling of Cones Subjected to Axial Compression and External Pressure

2011 ◽  
Author(s):  
J. Blachut ◽  
A. Muc ◽  
J. Rys´
Keyword(s):  
Axial Compression ◽  
Wall Thickness ◽  
Failure Load ◽  
Thickness Distribution ◽  
True Strain ◽  
Cone Angle ◽  
External Pressure ◽  
Large Radius ◽  
Perfectly Plastic ◽  
Failure Loads

The paper provides details about buckling tests on six steel cones and the corresponding numerical estimates of failure load (asymmetric bifurcation and/or collapse). Test models were machined from 250 mm billet. The wall thickness was 2 mm, small-end radius was 74.0 mm and the large radius end was 100 mm. The semi-cone angle was 14 deg. Cones had substantial, and integral top and bottom flanges. Experimental failure loads were obtained for: (i) the first two cones subjected to axial compression, (ii) subsequent two cones subjected to external pressure, and (iii) the remaining two models subjected to combined action of external pressure and axial compression. The magnitude of test pressure was about 5 MPa, and the axial failure load was approximately 230 kN. Good repeatability of experimental failure loads was obtained. Numerical estimates of failure loads were obtained for elastic perfectly plastic, engineering stress-strain, and true stress–true strain modelling of steel. Apart from axisymmetric modelling of shells, true geometry with true wall thickness distribution was adopted in calculations. Some of the numerical estimates of buckling loads are close to test data but other are not. The reasons for these discrepancies are highlighted in the paper.

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