Dynamic Stress Analysis of Multilayered Structure With Radial Gaps of Cylindrical Pressure Vessel Under Plane Strain Conditions

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Huadong Liu ◽  
Weiqiang Wang
Keyword(s):  
Plastic Deformation ◽  
Dynamic Response ◽  
Plane Strain ◽  
Pressure Vessel ◽  
Single Layer ◽  
Multilayered Structure ◽  
Multilayered Structures ◽  
Loading Process ◽  
Cylindrical Pressure Vessel ◽  
Gap Height

Radial gaps were found in multilayered cylindrical vessels which experience inner explosion accidents in chemical plants in the past few years worldwide. It is necessary to investigate the dynamic response of multilayered structures with radial gaps to ensure the vessel safety. This paper presented a numerical modeling of the dynamic response of a multilayered structure with radial gaps of cylindrical pressure vessel under plane strain conditions by using the ANSYS/ls-dyna package. The effects of the dynamic loading profile and the radial gap height are considered in the investigation. The stress spatial distribution, the stress and the plastic deformation variation curves with time are emphatically analyzed. The results show that the stress variation of the entire loading process can be divided into four stages: the oscillation stage, the yield stage, the fast increase stage, and the redistribution stage. The layer stress distributes discontinuously at the gaps between layers and distributes unevenly in any single layer. The inner layer stress is not always larger than the outer layers' during the whole loading process. The effect of loading profile on the dynamic response is not as obvious as the gap height. As the gap height increases, the stress oscillation stage is suppressed and becomes shorter. While the loading recovers to the operation pressure, the stress and the plastic deformation of inner layers increases and vice versa for the outer layers.

Obtaining an Optimum Weight for a Composite Pressure Vessel

2010 ◽  
Vol 636-637 ◽  
pp. 1105-1111
Author(s):  
S. Moharrerzadeh ◽  
A. Atai
Keyword(s):  
Pressure Vessel ◽  
Volume Fraction ◽  
Optimization Technique ◽  
Multilayered Structure ◽  
Layered Composite ◽  
Number Of Layers ◽  
Design Variables ◽  
Cylindrical Pressure Vessel ◽  
Composite Pressure Vessel ◽  
Optimum Weight

Weight of a composite cylindrical pressure vessel is an important issue investigated here. Design variables include number of layers and thickness, ply angle, volume fraction, and material properties in each layer. The constraint is based on Hoffman criterion and the optimization technique is a messy genetic algorithm (mGA). It is shown that with multilayered structure, we can have a vessel with a weight less than half of that for a single layered composite vessel under a given internal pressure.

scholarly journals Numerical Analysis of Filament Wound Cylindrical Composite Pressure Vessels Accounting for Variable Dome Contour

2021 ◽  
Vol 5 (2) ◽  
pp. 56
Author(s):  
Kumar C. Jois ◽  
Marcus Welsh ◽  
Thomas Gries ◽  
Johannes Sackmann
Keyword(s):  
Stress Distribution ◽  
Pressure Vessel ◽  
Single Layer ◽  
Pressure Vessels ◽  
Filament Wound ◽  
Cylindrical Pressure Vessel ◽  
Composite Pressure Vessel ◽  
Polymer Liner ◽  
Specific Distance ◽  
Composite Pressure Vessels

In this work, the stress distribution along cylindrical composite pressure vessels with different dome geometries is investigated. The dome contours are generated through an integral method based on shell stresses. Here, the influence of each dome contour on the stress distribution at the interface of the dome-cylinder is evaluated. At first, the integral formulation for dome curve generation is presented and solved for the different dome contours. An analytical approach for the calculation of the secondary stresses in a cylindrical pressure vessel is introduced. For the analysis, three different cases were investigated: (i) a polymer liner; (ii) a single layer of carbon-epoxy composite wrapped on a polymer liner; and (iii) multilayer carbon-epoxy pressure vessel. Accounting for nonlinear geometry is seen to have an effect on the stress distribution on the pressure vessel, also on the isotropic liner. Significant secondary stresses were observed at the dome-cylinder interface and they reach a maximum at a specific distance from the interface. A discussion on the trend in these stresses is presented. The numerical results are compared with the experimental results of the multilayer pressure vessel. It is observed that the secondary stresses present in the vicinity of the dome-cylinder interface has a significant effect on the failure mechanism, especially for thick walled cylindrical composite pressure vessel. It is critical that these secondary stresses are directly accounted for in the initial design phase.

Some classical problems in rate-independent plasticity

2020 ◽  
pp. 434-459
Author(s):  
Lallit Anand ◽  
Sanjay Govindjee
Keyword(s):  
Plane Strain ◽  
Analytical Solutions ◽  
Pressure Vessel ◽  
Plastic Response ◽  
Spring Back ◽  
Elastic Plastic ◽  
Initial Yield ◽  
Cylindrical Pressure Vessel ◽  
Round Bar ◽  
Spherical Pressure

This chapter presents analytical solutions to some classical problems in rate-independent plasticity. Solutions are presented for the elastic-plastic torsion of a round bar, including spring back; for the elastic-plastic response of a thick-walled spherical pressure vessel, including initial yield, partial yield, full yield, and unloading; for the incompressible elastic-plastic response of a plane-strain thick-walled cylindrical pressure vessel, including initial yield, partial yield, and full yield.

scholarly journals Vibration analysis of a sandwich cylindrical shell in hygrothermal environment

2021 ◽  
Vol 10 (1) ◽  
pp. 414-430
Author(s):  
Chunwei Zhang ◽  
Qiao Jin ◽  
Yansheng Song ◽  
Jingli Wang ◽  
Li Sun ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequency ◽  
Equations Of Motion ◽  
Single Layer ◽  
Functionally Graded ◽  
Sandwich Shell ◽  
Continuous Change ◽  
Multilayered Structures ◽  
Cylindrical Sandwich Shell ◽  
Vibrational Behavior

Abstract The sandwich structures are three- or multilayered structures such that their mechanical properties are better than each single layer. In the current research, a three-layered cylindrical shell including a functionally graded porous core and two reinforced nanocomposite face sheets resting on the Pasternak foundation is used as model to provide a comprehensive understanding of vibrational behavior of such structures. The core is made of limestone, while the epoxy is utilized as the top and bottom layers’ matrix phase and also it is reinforced by the graphene nanoplatelets (GNPs). The pattern of the GNPs dispersion and the pores distribution play a crucial role at the continuous change of the layers’ properties. The sinusoidal shear deformation shells theory and the Hamilton’s principle are employed to derive the equations of motion for the mentioned cylindrical sandwich shell. Ultimately, the impacts of the model’s geometry, foundation moduli, mode number, and deviatory radius on the vibrational behavior are investigated and discussed. It is revealed that the natural frequency and rotation angle of the sandwich shell are directly related. Moreover, mid-radius to thickness ratio enhancement results in the natural frequency reduction. The results of this study can be helpful for the future investigations in such a broad context. Furthermore, for the pipe factories current study can be effective at their designing procedure.

Research of stamping of unequal channel bars. Part 4. Deformed state of the workpiece when extruding channels. 2. Deformations under the punch end

2021 ◽  
pp. 53-57
Author(s):  
A.L. Vorontsov
Keyword(s):  
Plastic Deformation ◽  
Plane Strain ◽  
Deformation Zone ◽  
Plastic Deformation Zone ◽  
Die Forging ◽  
Deformed State

Determination of the deformed state of the workpiece at free extrusion of channels is considered. Formulas are obtained for determining the accumulated deformations at a given point of the plastic deformation zone and extruded walls of the product for any punch working stroke. Keywords: die forging, extrusion, misalignment, punch, matrix, plane strain, accumulated deformations, hardening. [email protected]

scholarly journals Characteristics of Oceanic Warm Cloud Layers within Multilevel Cloud Systems Derived by Satellite Measurements

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 465 ◽  
Author(s):  
Yuhao Ding ◽  
Qi Liu ◽  
Ping Lao
Keyword(s):  
Double Layer ◽  
Lower Layer ◽  
Single Layer ◽  
Distribution Patterns ◽  
Radar Data ◽  
Multilayered Structures ◽  
Layer System ◽  
Cloud Systems ◽  
Warm Cloud ◽  
Double Layer System

Low-level warm clouds are a major component in multilayered cloud systems and they are generally hidden from the top-down view of satellites with passive measurements. This study conducts an investigation on oceanic warm clouds embedded in multilayered structures by using spaceborne radar data with fine vertical resolution. The occurrences of warm cloud overlapping and the geometric features of several kinds of warm cloud layers are examined. It is found that there are three main types of cloud systems that involve warm cloud layers, including warm single layer clouds, cold-warm double layer clouds, and warm-warm double layer clouds. The two types of double layer clouds account for 23% and in the double layer occurrences warm-warm double layer subsets contribute about 13%. The global distribution patterns of these three types differ from each other. Single-layer warm clouds and the lower warm clouds in the cold-warm double layer system they have nearly identical geometric parameters, while the upper and lower layer warm clouds in the warm-warm double layer system are distinct from the previous two forms of warm cloud layers. In contrast to the independence of the two cloud layers in cold-warm double layer system, the two kinds of warm cloud layers in the warm-warm double layer system may be coupled. The distance between the two layers in the warm-warm double layer system is weakly dependent on cloud thickness. Given the upper and lower cloud layer with moderate thickness of around 1 km, the cloudless gap reaches its maximum when exceeding 600 m. The cloudless gap decreases in thickness as the two cloud layers become even thinner or thicker.

scholarly journals Design and Fabrication of a Modified Portable Biogas Digester for Renewable Cooking-Gas Production

2018 ◽  
Vol 3 (3) ◽  
pp. 21
Author(s):  
Barinyima Nkoi ◽  
Barinadaa Thaddeus Lebele-Alawa ◽  
Benedict Odobeatu
Keyword(s):  
Pressure Vessel ◽  
Storage Tank ◽  
Raw Materials ◽  
Gas Production ◽  
Smoke Detector ◽  
Cow Dung ◽  
Nickel Steel ◽  
Cylindrical Pressure Vessel ◽  
Test Pressure ◽  
Materials Used

This research paper focuses on re-engineering design and fabrication of a modified potable biogas digester for the production of biogas as a renewable energy source for domestic use. Digesters used around the world are commonly big in size. There is need to modify and re-engineer an existing biogas digester to fit in to modern day design for better efficiency, portability and safety. Floating drum and Flexible balloon are digesters to be modified as a thin walled pressure vessel with radius-thickness ratio  greater than 10. ASME codes and standards were used to carry out the sizing calculations, thickness and pressure calculations for the cylindrical pressure vessel shells and also calculations for the storage tank hemisphere shell. AISI 304 (Chromium-Nickel steel) is used for the vessel shell and the maximum allowable stress is 137 MPa. Weld efficiency (85%), corrosion allowance (0.02mm),  of 24 (for digester),  of 18 (for collector) and  of 20 (storage tank). 17 kg of cow dung and 34 kg of water with temperature of 32oC were the raw materials used for this research to produce a cumulative gas volume of 0.1243 m3 for 30 days. Furthermore, a bike pump is modified and used to increase methane gas pressure from 4.903 kPa to 345 kPa to suit the modern day gas cookers design and storage tank. Unlike other biogas plant, an electronic smoke alarm detector (model: Ei100) is placed 300 mm below the digester top for effective fire protection. Series of tests were performed to ensure that the constructed prototype met the specifications/standards. Such test include, smoke detector test, pressure testing, gas leak test, and a unit test run also confirmed that the aim of research was achieved.

To Analyze the Effects of Geometric Misalignment in a Cylindrical Pressure Vessel

2012 ◽  
Vol 152-154 ◽  
pp. 964-969 ◽  
Author(s):  
Musharaf Abbas ◽  
Asif Israr ◽  
Atiq Ur Rehman
Keyword(s):  
Finite Element ◽  
Alloy Steel ◽  
Pressure Vessel ◽  
Structural Integrity ◽  
High Strength ◽  
Fe Analysis ◽  
Low Alloy Steel ◽  
Affected Area ◽  
Cylindrical Pressure Vessel ◽  
Geometrical Effects

This particular work consider a pressurized vessel typically made of high strength low alloy steel and containing the geometric misalignment at the cylinder-to-cylinder junction. This misalignment produce in the vessel’s structure is because of girth weld that is evident in most of the fabrication of such type of structures apart from other factors which is beyond the scope of this study. This study evaluates the geometrical effects of mismatch on the structural integrity of the pressure vessel and prediction of stresses at the affected area of the cylinder. Analytical and Finite Element (FE) approaches are employed to analyze the configuration. FE analysis is performed by the use of ANSYS on one quarter of the structure due to symmetry. FE results are also compared with the analytical results of different authors. In addition, maximum allowable mismatch is also determined and is a part of this study.

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