Uncertainty in Collapse Strength Prediction of Sandwich Pipelines

2021 ◽  
Author(s):  
U. Bhardwaj ◽  
A. P. Teixeira ◽  
C. Guedes Soares
Keyword(s):  
Probabilistic Models ◽  
Uncertainty Propagation ◽  
Simulation Method ◽  
External Pressure ◽  
Design Parameters ◽  
Collapse Strength ◽  
Parameters Uncertainty ◽  
Wide Range ◽  
Model Predictions ◽  
Strength Models

Abstract This paper assesses the uncertainty in the collapse strength of sandwich pipelines under external pressure predicted by various strength models in three categories based on interlayer adhesion conditions. First, the validity of the strength models is verified by comparing their predictions with sandwich pipeline collapse test data and the corresponding model uncertainty factors are derived. Then, a parametric analysis of deterministic collapse strength predictions by models is conducted, illustrating insights of models’ behaviour for a wide range of design configurations. Furthermore, the uncertainty among different model predictions is perceived at different configurations of outer and inner pipes and core thicknesses. A case study of a realistic sandwich pipeline is developed, and probabilistic models are defined to basic design parameters. Uncertainty propagation of models’ predictions is assessed by the Monte Carlo simulation method. Finally, the strength model predictions of sandwich pipelines are compared to that of an equivalent single walled pipe.

Reliability Analysis of Pipelines With Local Corrosion Defects Under External Pressure

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
A. P. Teixeira ◽  
O. G. Palencia ◽  
C. Guedes Soares
Keyword(s):  
Model Uncertainty ◽  
External Pressure ◽  
Experimental Results ◽  
Local Corrosion ◽  
Design Code ◽  
Uncertainty Factors ◽  
Corrosion Defect ◽  
Collapse Strength ◽  
Corrosion Defects ◽  
Strength Models

This paper aims at assessing the reliability of pipelines with local corrosion defects subjected to external pressure. Several collapse strength models are calibrated and then used to formulate the reliability problem of corroded pipelines. Model uncertainty factors are derived for the various collapse strength models based on available experimental results to better predict the effect of local corrosion defects on the reduction of the collapse strength of pipelines. The model uncertainty factor is defined as function of the depth of the local corrosion defect and calibrates the overconservative predictions of collapse strength models that deal with the effect of corrosion defects by considering a uniform reduction of the pipe thickness. The collapse strength models together with the corresponding model uncertainty factors are then used to formulate the reliability problem of pipelines with local corrosion defects subjected to external pressure. Parametric and sensitivity analyses are performed for different levels of corrosion damages to identify the influence of the various parameters on the collapse probability of corroded pipelines under external pressure. Finally, an approach is suggested to calibrate a design code formulation that is conservative when the minimum pipe thickness is used to represent a local corrosion defect. The approach consists of identifying an equivalent depth of the corrosion defect, corresponding to an intermediate thickness of the corroded pipeline larger than the minimum thickness, that adjusts the design code to match the safety levels of the collapse strength model calibrated to the experimental results.

Estimation of Light Commercial Vehicles Dynamics by Results of Road Tests and Simulation

2014 ◽  
Author(s):  
Anton Tumasov ◽  
Anatoly Groshev ◽  
Roman Musarsky ◽  
Galina Konikova ◽  
Yury Trusov ◽  
...  
Keyword(s):  
Simulation Method ◽  
Design Parameters ◽  
Active Safety ◽  
Commercial Vehicles ◽  
Light Commercial Vehicle ◽  
Wide Range ◽  
Different Types ◽  
Suspension Stiffness ◽  
Multi Body ◽  
The Relationship

The chassis of light commercial vehicle (LCV) could be used for creating a wide range of vehicles modifications with the similar base (chassis), but really different performance in wide range of maneuvers. The differences could be explained by variety of design parameters. It means that the design of LCV modifications needs some effective approach that will provide an engineer by necessary data that could help to estimate the performance of new vehicles in particular active safety characteristics. This paper presents the combination of experimental and simulation methods that could be used for estimation of LCV active safety characteristics (first of all cornering stability). The experimental method of estimation of cornering stability is shown that is based on regulations of the Russian Standard GOST R 52302-2004 that presuppose different types of testing: static rollover and dynamic maneuvering on a road (line changing and running into the corner). The multi-body simulation method with using of MSC.ADAMS/CAR software was also used in a study. The approval of developed LCV multi-body model was made on a basis of good correlation between simulation results and experimental data. The relationship between LCVs design parameters (axle load distribution, height of the center of gravity, vertical and angular suspension stiffness) and active safety characteristics are received.

scholarly journals Modelling with star-shaped distributions

2020 ◽  
Vol 8 (1) ◽  
pp. 45-69
Author(s):  
Eckhard Liebscher ◽  
Wolf-Dieter Richter
Keyword(s):  
Probabilistic Models ◽  
Arbitrary Dimension ◽  
Probability Density Functions ◽  
Density Functions ◽  
Wide Range ◽  
Gaussian Density ◽  
Spherical Distributions ◽  
Data Points ◽  
Non Gaussian ◽  
General Method

AbstractWe prove and describe in great detail a general method for constructing a wide range of multivariate probability density functions. We introduce probabilistic models for a large variety of clouds of multivariate data points. In the present paper, the focus is on star-shaped distributions of an arbitrary dimension, where in case of spherical distributions dependence is modeled by a non-Gaussian density generating function.

scholarly journals Study on Friction in Automotive Shock Absorbers Part 1: Friction Simulation Using a Dynamic Friction Model in the Contact Zone of an FEM Model

Vehicles ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 212-232
Author(s):  
Ludwig Herzog ◽  
Klaus Augsburg
Keyword(s):  
Ride Comfort ◽  
Viscous Friction ◽  
Simulation Method ◽  
Friction Model ◽  
Model Parameters ◽  
Dynamic Friction ◽  
Friction Modeling ◽  
Shock Absorbers ◽  
Operation Conditions ◽  
Wide Range

The important change in the transition from partial to high automation is that a vehicle can drive autonomously, without active human involvement. This fact increases the current requirements regarding ride comfort and dictates new challenges for automotive shock absorbers. There exist two common types of automotive shock absorber with two friction types: The intended viscous friction dissipates the chassis vibrations, while the unwanted solid body friction is generated by the rubbing of the damper’s seals and guides during actuation. The latter so-called static friction impairs ride comfort and demands appropriate friction modeling for the control of adaptive or active suspension systems. In this article, a simulation approach is introduced to model damper friction based on the most friction-relevant parameters. Since damper friction is highly dependent on geometry, which can vary widely, three-dimensional (3D) structural FEM is used to determine the deformations of the damper parts resulting from mounting and varying operation conditions. In the respective contact zones, a dynamic friction model is applied and parameterized based on the single friction point measurements. Subsequent to the parameterization of the overall friction model with geometry data, operation conditions, material properties and friction model parameters, single friction point simulations are performed, analyzed and validated against single friction point measurements. It is shown that this simulation method allows for friction prediction with high accuracy. Consequently, its application enables a wide range of parameters relevant to damper friction to be investigated with significantly increased development efficiency.

Near-Wall Microlayer Evaporation Analysis and Experimental Study of Nucleate Pool Boiling on Inclined Surfaces

1998 ◽  
Vol 120 (3) ◽  
pp. 641-653 ◽  
Author(s):  
G. F. Naterer ◽  
W. Hendradjit ◽  
K. J. Ahn ◽  
J. E. S. Venart
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heating Surface ◽  
Nucleate Boiling ◽  
Inclined Surfaces ◽  
Wide Range ◽  
Model Predictions ◽  
Microlayer Evaporation ◽  
Near Wall

Boiling heat transfer from inclined surfaces is examined and an analytical model of bubble growth and nucleate boiling is presented. The model predicts the average heat flux during nucleate boiling by considering alternating near-wall liquid and vapor periods. It expresses the heat flux in terms of the bubble departure diameter, frequency and duration of contact with the heating surface. Experiments were conducted over a wide range of upward and downward-facing surface orientations and the results were compared to model predictions. More active microlayer agitation and mixing along the surface as well as more frequent bubble sweeps along the heating surface provide the key reasons for more effective heat transfer with downward facing surfaces as compared to upward facing cases. Additional aspects of the role of surface inclination on boiling dynamics are quantified and discussed.

scholarly journals Multi-stable composite twisting structure for morphing applications

2012 ◽  
Vol 468 (2141) ◽  
pp. 1230-1251 ◽  
Author(s):  
X. Lachenal ◽  
P. M. Weaver ◽  
S. Daynes
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Design Parameters ◽  
Engineering Structures ◽  
The Past ◽  
Wide Range ◽  
Morphing Structure ◽  
Low Mass ◽  
Unstable States

Conventional shape-changing engineering structures use discrete parts articulated around a number of linkages. Each part carries the loads, and the articulations provide the degrees of freedom of the system, leading to heavy and complex mechanisms. Consequently, there has been increased interest in morphing structures over the past decade owing to their potential to combine the conflicting requirements of strength, flexibility and low mass. This article presents a novel type of morphing structure capable of large deformations, simply consisting of two pre-stressed flanges joined to introduce two stable configurations. The bistability is analysed through a simple analytical model, predicting the positions of the stable and unstable states for different design parameters and material properties. Good correlation is found between experimental results, finite-element modelling and predictions from the analytical model for one particular example. A wide range of design parameters and material properties is also analytically investigated, yielding a remarkable structure with zero stiffness along the twisting axis.

Closed-Form Correlation of Buildings Energy Use With Key Design Parameters Calibrated Using a Genetic Algorithm

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Raed I. Bourisli ◽  
Adnan A. AlAnzi
Keyword(s):  
Genetic Algorithm ◽  
Closed Form ◽  
Energy Use ◽  
Building Design ◽  
Office Buildings ◽  
Design Parameters ◽  
Wide Range ◽  
Variable Function ◽  
Real Coded Genetic Algorithm ◽  
The Difference

This work aims at developing a closed-form correlation between key building design variables and its energy use. The results can be utilized during the initial design stages to assess the different building shapes and designs according to their expected energy use. Prototypical, 20-floor office buildings were used. The relative compactness, footprint area, projection factor, and window-to-wall ratio were changed and the resulting buildings performances were simulated. In total, 729 different office buildings were developed and simulated in order to provide the training cases for optimizing the correlation’s coefficients. Simulations were done using the VisualDOE TM software with a Typical Meteorological Year data file, Kuwait City, Kuwait. A real-coded genetic algorithm (GA) was used to optimize the coefficients of a proposed function that relates the energy use of a building to its four key parameters. The figure of merit was the difference in the ratio of the annual energy use of a building normalized by that of a reference building. The objective was to minimize the difference between the simulated results and the four-variable function trying to predict them. Results show that the real-coded GA was able to come up with a function that estimates the thermal performance of a proposed design with an accuracy of around 96%, based on the number of buildings tested. The goodness of fit, roughly represented by R2, ranged from 0.950 to 0.994. In terms of the effects of the various parameters, the area was found to have the smallest role among the design parameters. It was also found that the accuracy of the function suffers the most when high window-to-wall ratios are combined with low projection factors. In such cases, the energy use develops a potential optimum compactness. The proposed function (and methodology) will be a great tool for designers to inexpensively explore a wide range of alternatives and assess them in terms of their energy use efficiency. It will also be of great use to municipality officials and building codes authors.

Integrated Heterogeneous Micro-Nano Systems via Modular Designing and Flexible Assembly

2011 ◽  
Author(s):  
Aditya Das ◽  
Rakesh Murthy
Keyword(s):  
Uncertainty Propagation ◽  
Systems Development ◽  
Surface Machining ◽  
Flexible Assembly ◽  
Nano Scale ◽  
Wide Range ◽  
Standard Design ◽  
Novel Algorithms ◽  
And Control ◽  
Dedicated Hardware

One of the major challenges in commercializable micro-nano systems development is the high cost and turnaround that are incurred through multiple product-optimization iterations and expensive fabrication processes for specific systems. Development of complex and heterogeneous micro-nano systems, that are only possible through assembly and not by conventional surface machining approaches, are further impeded by lack of standard design rules and off-the-shelf robotic manipulation systems. Dedicated hardware and system specific component designs, although possible, are not commercially viable for addressing the wide range of opportunities that exists in the prevailing micro-nano domain. In this paper, we present an alternative and holistic top-down approach for micro-nano manufacturing using modular part designs and flexible assembly systems. We incorporate, seamlessly, multiple novel algorithms related to microrobotics and scaling of physics, obtained both analytically as well as experimentally; in order to predict, track and control the uncertainty propagation in a typical manufacturing process, in micro-nano scale, throughout production steps including design, machining, setup, assembly, testing etc. We demonstrate, through multiple examples, the implementation of the proposed framework in micro-nano scale manufacturing.

Constrained Minimum Discrimination Information: A Unifying Tool for Modeling Spatial and Individual Choice Behavior

1982 ◽  
Vol 14 (10) ◽  
pp. 1341-1354 ◽  
Author(s):  
K E Haynes ◽  
F Y Phillips
Keyword(s):  
Choice Behavior ◽  
Applied Research ◽  
Probabilistic Models ◽  
Estimation Methods ◽  
Regression Estimation ◽  
Individual Choice ◽  
Wide Range ◽  
Alternative Hypotheses ◽  
Discrimination Information ◽  
Minimum Discrimination Information

Mathematical programming and statistical inference are combined in a constrained minimum discrimination information (MDI) method to provide a basis for a wide range of spatial and individual choice behavior problems. This approach offers an alternative to linear and loglinear regression estimation methods as well as probabilistic models of the logit and probit variety. Some logical and computational difficulties inherent in these approaches are resolved. Further, the approach leads endogenously to alternative hypotheses if the null hypothesis is rejected, and hence has implications for the interaction between research that is oriented toward theory construction and applied research that is empirically oriented.

Application areas of the angle reflector

2021 ◽  
pp. 54-59
Author(s):  
L. R. Yurenkova ◽  
O. A. Yakovuk ◽  
I. V. Morozov
Keyword(s):  
Radio Wave ◽  
Outer Space ◽  
Road Transport ◽  
Optical Systems ◽  
Design Parameters ◽  
Design Activity ◽  
Primary Role ◽  
Beam Laser ◽  
Wide Range ◽  
Graphical Calculation

The article provides examples of how the device known as the «angle reflector» a few decades ago has been increasingly used in various fields of science and technology in recent years. Angle reflectors are designed to change (reflect) optical and radar rays in the direction, opposite to the original direction. At present, angle reflectors are widely used to ensure the safety of road transport on dangerous road sections. Radio wave reflectors have the same design as optical ones; therefore, in radio detection and location, angle reflectors are used to send warning signals to ship radars on bridge supports, beacons and buoys. Modern angle reflectors attached to meteorological probes allow determining the direction and speed of the wind at high altitude, which is especially important in the study of the outer space. In recent years, devices have been developed to improve the accuracy of radar stations calibration. The examples of graphical calculation of angle reflectors presented in the article clearly demonstrate the primary role of geometry in the design activity of an engineer. The graphical calculation is based on the theoretical positions of projective geometry. The design and calculation of optical systems is carried out by the graphoanalytic method, since only with a combination of graphical and analytical methods it is possible to accurately calculate the course of a light beam, laser, or radio wave and thereby determine the design parameters of the devices. The article focuses on a graphical method for calculating two types of angle reflectors using orthogonal projection, due to which modern engineers will be able to create more up-to-date designs of optical systems with a wide range of applications.

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