Reliability Design of Flexible Airfield Pavements: Elastic Layered Method

1997 ◽  
Vol 1568 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Yu T. Chou
Keyword(s):  
Prediction Models ◽  
Design Procedure ◽  
Design System ◽  
Mean Values ◽  
Reliability Design ◽  
Reliability Level ◽  
Lack Of Fit ◽  
User Friendly ◽  
Pavement Thickness ◽  
Independent Parameters

A design procedure was developed for layered elastic flexible airfield pavement systems in terms of probability and reliability. A user-friendly computer program, RELIFLEX, was prepared to carry out the computations. The Rosenblueth method is used to estimate the expected value and variance of the computed strains (dependent parameters) on the basis of the input mean values of independent parameters (i.e., aircraft load, layer thicknesses, and material moduli). RELIFLEX has the capability of considering the strain distribution to be normal, lognormal, or beta, and a capacity-demand analysis is included. Only normal distribution is presented. Environmental effects and the lack of fit of the prediction models are not considered in RELIFLEX. The relationships between the reliability level and the allowable strain repetition of the designed system, established using RELIFLEX, provide a decision-making tool for engineers to design pavement at the desired reliability level. For a desired reliability level of the design system, pavement thickness can be varied to agree with the designed coverage or the allowable coverage can be modified for a given pavement thickness.

Design Nomographs of Compression Helical Springs for Predetermined Reliability Levels

1981 ◽  
Vol 103 (2) ◽  
pp. 268-273
Author(s):  
My Dao Thien ◽  
M. Massoud
Keyword(s):  
Probabilistic Approach ◽  
Design Procedure ◽  
Axial Loading ◽  
Geometric Parameters ◽  
Computer Algorithms ◽  
Mean Values ◽  
Helical Springs ◽  
Reliability Level ◽  
Classical Design ◽  
Mission Success

This paper discusses a probabilistic approach for the design of Compression Closely Coiled Helical Springs subjected to periodic axial loading. The classical design procedure results in deterministic geometric parameters with tolerances normally chosen according to standards without due regard to their effects on the mission success as normally expressed by a reliability level. With the proposed design procedure, the engineer can specify nominal mean values for the geometric parameters and their tolerances according to a predetermined reliability level. Design nomographs are presented to help the engineer, in the early stages of design, to choose between many alternatives. Computer algorithms can easily be written to verify the final or optimum design.

Modified Portland Cement Association Stress Analysis and Thickness Design Procedures

1997 ◽  
Vol 1568 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Ying-Haur Lee ◽  
Jean-Hwa Bair ◽  
Chao-Tsung Lee ◽  
Shao-Tang Yen ◽  
Ying-Ming Lee
Keyword(s):  
Portland Cement ◽  
Stress Analysis ◽  
Prediction Models ◽  
Equivalent Stress ◽  
Design Procedure ◽  
Concrete Pavements ◽  
Spreadsheet Program ◽  
Practical Trial ◽  
Portland Cement Association ◽  
User Friendly

A new stress analysis and thickness design procedure for jointed concrete pavements was developed. On the basis of Westergaard’s edge stress solution and several prediction models for stress adjustments for a variety of loading and environmental (i.e., thermal curling) conditions, a modified Portland Cement Association (PCA) equivalent stress analysis and thickness design procedure was proposed and implemented in a highly user-friendly, Windows-based program, TKUPAV, for practical trial applications. The proposed approach has been further verified by reproducing results very close to the PCA’s equivalent stresses and fatigue damages using a spreadsheet program and the TKUPAV program. The possible detrimental effect of loading plus daytime curling has been illustrated in a case study, which also indicated that the effect of thermal curling should be considered in the thickness design of concrete pavements.

Mechanistically Based Flexible Overlay Design System for Idaho

1996 ◽  
Vol 1543 (1) ◽  
pp. 10-19 ◽  
Author(s):  
Fouad M. Bayomy ◽  
Fawzi A. Al-Kandari ◽  
Robert M. Smith
Keyword(s):  
Design Procedure ◽  
Failure Criteria ◽  
The State ◽  
Design System ◽  
Falling Weight Deflectometer ◽  
Overlay Design ◽  
Pavement Damage ◽  
Critical Strains ◽  
Falling Weight ◽  
User Friendly

A study was conducted on a mechanistically based overlay design procedure that incorporates the in situ pavement layer modulus values evaluated by deflection-based nondestructive testing using falling weight deflectometer data. The proposed overlay design procedure addresses the seasonal variation in the state of Idaho and adjusts the modulus values accordingly. The performance of the pavement is calculated in terms of critical strains based on the elastic multilayer theory. The study adopts the Asphalt Institute fatigue and rutting failure criteria to calculate the life of the pavement. Damage analysis is performed based on the past and expected future traffic to calculate the required overlay thickness. The procedure developed has been implemented in an event-driven, user-friendly computer program FLEXOLAY, which runs in the DOS environment. The program was tested and compared with other overlay design methods using pavement sections from the state of Idaho. The overlay thickness determined by FLEXOLAY was found to be close to some of the existing methods and far from others, depending on the existing pavement conditions.

scholarly journals Covid19Risk.ai: An open source repository and online calculator of prediction models for early diagnosis and prognosis of Covid-19

2021 ◽  
Author(s):  
Iva Halilaj ◽  
Avishek Chatterjee ◽  
Yvonka van Wijk ◽  
Guangyao Wu ◽  
Brice van Eeckhout ◽  
...  
Keyword(s):  
Open Source ◽  
Predictive Models ◽  
Prediction Models ◽  
Patient Specific ◽  
Diagnosis And Prognosis ◽  
Online Calculator ◽  
User Friendly ◽  
Type 3 ◽  
Proof Of Principle

AbstractObjectiveThe current pandemic has led to a proliferation of predictive models being developed to address various aspects of COVID-19 patient care. We aimed to develop an online platform that would serve as an open source repository for a curated subset of such models, and provide a simple interface for included models to allow for online calculation. This platform would support doctors during decision-making regarding diagnoses, prognoses, and follow-up of COVID-19 patients, expediting the models’ transition from research to clinical practice.MethodsIn this proof-of-principle study, we performed a literature search in PubMed and WHO database to find suitable models for implementation on our platform. All selected models were publicly available (peer reviewed publications or open source repository) and had been validated (TRIPOD type 3 or 2b). We created a method for obtaining the regression coefficients if only the nomogram was available in the original publication. All predictive models were transcribed on a practical graphical user interface using PHP 8.0.0, and published online together with supporting documentation and links to the associated articles.ResultsThe open source website https://covid19risk.ai/ currently incorporates nine models from six different research groups, evaluated on datasets from different countries. The website will continue to be populated with other models related to COVID-19 prediction as these become available. This dynamic platform allows COVID-19 researchers to contact us to have their model curated and included on our website, thereby increasing the reach and real-world impact of their work.ConclusionWe have successfully demonstrated in this proof-of-principle study that our website provides an inclusive platform for predictive models related to COVID-19. It enables doctors to supplement their judgment with patient-specific predictions from externally-validated models in a user-friendly format. Additionally, this platform supports researchers in showcasing their work, which will increase the visibility and use of their models.

Modeling of Gear Hobbing: Part II — A Computer Supported Experimental-Analytical Determination of the Wear Progress to Optimize the Tool Life Time

1999 ◽  
Author(s):  
Konstantinos D. Bouzakis ◽  
Spiros Kombogiannis ◽  
Aristomenis Antoniadis ◽  
Nectarios Vidakis
Keyword(s):  
Tool Wear ◽  
Prediction Models ◽  
Digital Simulation ◽  
Life Time ◽  
Analytical Determination ◽  
Tool Wear Prediction ◽  
Gear Hobbing ◽  
User Friendly ◽  
Continuous Enrichment

Abstract Tool wear prediction models for gear hobbing were presented in the first part of this paper. To determine the constants of the equations used in these models, fly hobbing experiments with uncoated and coated HSS tools were conducted. Hereby, it was necessary to modify the fly hobbing kinematics from continuous tangential feed to continuous axial feed. The experimental data were evaluated, and correlated to the analytical ones, elaborated through the described digital simulation of the cutting process. The determined constants of the wear laws for the investigated tools were used in a further developed user friendly software, enabling the prediction of the tool wear accomplishment in gear hobbing. On that account the wear development can be precisely foreseen and the tangential shift of the tool is optimized. The open and modular structure of the developed code enables the continuous enrichment of its database with other type of coating and workpiece materials. With the aid of the aforementioned techniques, the superiority of coated HSS tools in comparison to uncoated ones is also quantitatively exhibited.

Fertilized Midrotation-Aged Slash Pine Plantations—Stand Structure and Yield Prediction Models

1989 ◽  
Vol 13 (2) ◽  
pp. 76-80 ◽  
Author(s):  
Robert L. Bailey ◽  
Thomas M. Burgan ◽  
Eric J. Jokela
Keyword(s):  
Prediction Models ◽  
Stand Structure ◽  
Basal Area ◽  
Slash Pine ◽  
Pine Plantations ◽  
Individual Tree ◽  
Investment Opportunities ◽  
User Friendly ◽  
Volume Equations ◽  
Soil Groups

Abstract Data from 263 plots in a regional fertilization study of midrotation-aged slash pine plantations were used to fit prediction equations for basal area, trees per acre, stand average dominant height, diameter distributions, and individual tree heights. The equations include N and P fertilizationrates and CRIFF soil groups as predictor variables. The survival model also accounts for the accelerating effect of fusiform rust on mortality rate. Using published tree volume equations, the prediction of volumes by dbh class for fertilized slash pine plantations is now possible. This integratedsystem of equations is available as a user-friendly computer program that can calculate expected yields by diameter class and aid the forester in evaluating investment opportunities that include forest fertilization. South. J. Appl. For. 13(2):76-80.

Superpave Models: Predicting Performance during Design and Construction

1996 ◽  
Vol 1545 (1) ◽  
pp. 105-112
Author(s):  
Gerald A. Huber ◽  
Xishun Zhang ◽  
Robin Fontaine
Keyword(s):  
Prediction Models ◽  
Permanent Deformation ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Engineering Properties ◽  
Design System ◽  
Widespread Application ◽  
Premature Failure ◽  
The Impact

The Strategic Highway Research Program (SHRP) spent $50 million researching asphalt binders and asphalt mixtures and provided three main products: an asphalt binder specification, an asphalt mixture specification, and Superpave, an asphalt mixture design system that encompasses both the binder and mixture specification. SHRP researchers have provided tools that promise more robust asphalt mixtures with reduced risk of premature failure. Implementation of the specifications and mix design system will require overcoming several obstacles. Superpave must be demonstrated to be practical and easy to use. The impact of Superpave aggregate requirements on aggregate availability must be determined. The Superpave gyratory compaction procedure has been uniquely defined and then calibrated to traffic volume. The reasonableness of this approach must be tested in widespread application. Perhaps the largest implementation hurdle exists in the performance models. Expensive test equipment is necessary to do the performance-based tests. The performance predictions must be established as reasonable to justify the cost. A highway reconstruction project containing three Superpave Level 1 mix designs is documented including quality control done with the Superpave gyratory compactor. Superpave Level 2 performance-based tests were carried out to predict permanent deformation of the design and the mixture as constructed. The performance-based engineering properties obtained from the tests are evaluated, and the reasonableness of the performance prediction models is discussed.

Development and Application of a Synchronous Belt Drive Design System

2014 ◽  
Vol 971-973 ◽  
pp. 450-453 ◽  
Author(s):  
Yi Guo ◽  
Guo Liang Ding ◽  
Zhi Qiang Li
Keyword(s):  
3D Modeling ◽  
Spare Parts ◽  
Design System ◽  
Belt Drive ◽  
Design Calculation ◽  
Accurate Design ◽  
Basic Language ◽  
Synchronous Belt Drive ◽  
Visual Basic Language ◽  
User Friendly

To solve the synchronous belt drive design and 3D modeling problem, a synchronous belt drive design system has been developed with the Visual Basic language and SolidWorks platform. Applications have shown that this system can realize design calculation of the synchronous belt drive and the 3D modeling of spare parts and assemblies like the small belt pulley, large belt pulley and synchronous belt, as required by the customer. Also, it has a user-friendly interface, handy operation, simple operation, and accurate design results, to effectively shorten the design period.

An Aircraft Tooling Cooperative Design Model Based on Neuron-Endocrine-Immunity Working Principle

2008 ◽  
Vol 44-46 ◽  
pp. 239-246 ◽  
Author(s):  
Ying Guang Li ◽  
Zhi Yi Pan ◽  
R.J. Yan ◽  
J.B. Jian
Keyword(s):  
Design Procedure ◽  
Design Model ◽  
Design System ◽  
Chemical Information ◽  
Design Quality ◽  
Cooperative Design ◽  
Model Based ◽  
Aircraft Manufacturing ◽  
Working Principle ◽  
Tooling Design

As restricted by airplane R&D circle, aircraft tooling design is desired to comply with airplane product design and subsequent portions. However, cooperative design for aircraft tooling, especially large-sized one, is difficult and the reasons are as follows: ①The quantity for Aircraft tooling parts is enormously large, the size is large, and the structure is complex. ②Tooling design procedure is complicated with many portions to be coordinated. ③Airplane product amendments are frequent and hard to trace. Aircraft tooling design tends to proceed without effective mechanism to evaluate and optimize manufacturing process, scheduling and etc. With these difficulties considered, an aircraft tooling cooperative design model based on Neuron-Endocrine-Immunity working principle is presented in this paper. Resorting to shared chemical information molecules, Neuron-Endocrine-Immunity system forms an extensive and complicated regulating network which regulates all cells and tissues in human body. Referring to this principle, aircraft tooling design system involves controller and controlled objects. With adaptive and self-organized tooling design procedure, rapid adjustment or reconfiguration can be realized. Meanwhile, the feasibility and validity of adjusting task plans and tooling design schedules are ensured. To implement this model, a multi-agent-based framework for aircraft tooling cooperative design is proposed. This framework incorporates PDM and united structure for effective collaboration in terms of unified data sharing, convenient tool wrapping and decentralized control. A pilot system has been developed and testified in an aircraft manufacturing enterprise, thus lessening repetitive modifying workload, ensuring design quality and project schedule.

scholarly journals Development of User-Friendly Structural Design System for Pressure Vessels

1996 ◽  
Vol 39 (3) ◽  
pp. 354-361
Author(s):  
Takuya SATO ◽  
Taeko NOMOTO ◽  
Kenichiro KADO ◽  
Genki YAGAWA ◽  
Shinobu YOSHIMURA
Keyword(s):  
Structural Design ◽  
Pressure Vessels ◽  
Design System ◽  
User Friendly
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