Development of an improved design methodology and front steering design guideline for small-wheel bicycles for better stability and performance

2020 ◽  
Vol 234 (3) ◽  
pp. 227-244
Author(s):  
Milan Paudel ◽  
Fook Fah Yap
Keyword(s):  
Design Methodology ◽  
Design Guidelines ◽  
Design Approach ◽  
Design Parameters ◽  
Design Practice ◽  
Frame Design ◽  
Current Design ◽  
And Performance ◽  
Improved Design ◽  
Bicycle Design

The maneuverability and compactness of small-wheel and folding bicycles are greatly appreciated. Nonetheless, the performance of these small-wheel bicycles as compared to the big-wheel bicycles has always been questioned. They are often blamed for being less stable, wobbly, or twitchy. It is still unclear how the performance of the small-wheel bicycle designs can be improved. Both small- and big-wheel bicycles are designed with similar ergonomics; therefore, the focus has been on the front steering design. The steering design parameters of 91 big-wheel and 27 small-wheel bicycles were compared, bearing in mind the available front steering design guidelines to understand: (1) the influence of big-wheel bicycle’s frame design on small-wheel bicycles and (2) most common range of design parameters used in current bicycle designs. The analysis showed a strong influence of current big-wheel bicycle design practice on front frame parameter selection of small-wheel bicycles. Furthermore, the self-stability comparison over the most common design range confirmed the lesser stability in the current small-wheel bicycle designs at normal riding speed. However, it was also found that the lesser stability was not the result of small wheels per se, but rather owing to an inadequacy in the current design approach to addressing the complex influence of reducing wheel size and bicycle frame design on its stability and performance. Therefore, an improved design methodology was adopted by incorporating the bicycle dynamics into the current design approach and the front steering design guidelines for small-wheel bicycles have been developed. The guidelines contradict the current small-wheel bicycle design practice, as they recommend steeper headtube angles for small-wheel bicycles. The guidelines were validated with good agreement between the theoretical and experimental results on two prototype 20-inch-wheel bicycles having counter-intuitive steering geometry.

Front steering design guidelines formulation for e-scooters considering the influence of sitting and standing riders on self-stability and safety performance

2021 ◽  
pp. 095440702199217
Author(s):  
Milan Paudel ◽  
Fook Fah Yap
Keyword(s):  
Preventive Measures ◽  
Recent Trend ◽  
Dynamic Performance ◽  
Design Guidelines ◽  
Safety Performance ◽  
Design Parameters ◽  
Single Track ◽  
Standing Posture ◽  
Last Mile ◽  
Current Design

E-scooters are a recent trend and are viewed as a sustainable solution to ease the first and last mile problem in modern transportation. However, an alarming rate of accidents, injuries, and fatalities have caused a significant setback for e-scooters. Many preventive measures and legislation have been put on the e-scooters, but the number of accidents and injuries has not reduced considerably. In this paper, the current design approach of e-scooters has been analyzed, and the most common range of design parameters have been identified. Thereafter, validated mathematical models have been used to quantify the performance of e-scooters and relate them with the safety aspects. Both standing and seated riders on e-scooters have been considered, and their influence on the dynamic performance has been analyzed and compared with the standard 26-in wheel reference safety bicycle. With more than 80% of the accidents and injuries occurring from falling or colliding with obstacles, this paper tries to correlate the dynamics of uncontrolled single-track vehicles with the safety performance of e-scooters. The self-stability, handling, and braking effect have been considered as major performance matrices. The analysis has shown that the current e-scooter designs are not as stable as the reference safety bicycle. Moreover, these e-scooters have been found unstable within the most common range of legislated riding velocity. The results corroborate with the general perception that the current designs of e-scooters are less stable, easy to lose control, twitchy, or wobbly to ride. Furthermore, the standing posture of the rider on the e-scooter has been found dangerous while braking to avoid any disturbances such as potholes or obstacles. Finally, the front steering design guidelines have been proposed to help modify the current design of e-scooters to improve the dynamic performance, hence the safety of the e-scooter riders and the surroundings.

Reliability-Based Limit States Design for Onshore Pipelines

2002 ◽  
Author(s):  
Maher Nessim ◽  
Tom Zimmerman ◽  
Alan Glover ◽  
Martin McLamb ◽  
Brian Rothwell ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Traditional Approach ◽  
Large Diameter ◽  
Small Diameter ◽  
Mechanical Damage ◽  
Design Approach ◽  
Design Parameters ◽  
Pipe Failure ◽  
Limit States ◽  
Current Design

The traditional approach to pipelines design is to select a wall thickness that maintains the hoop stress below the yield strength multiplied by a safety factor. The main design condition implied by this approach is yielding (and by extension burst) of the defect-free pipe. Failure statistics show that this failure mode is virtually impossible as the majority of failures occur due to equipment impact and various types of defects such as corrosion and cracks. Recent investigations show that these failure causes are much more sensitive to wall thickness than to steel grade. As a consequence, current design methods produce variable levels of safety for different pipelines — small-diameter, low-pressure pipelines for example have been shown to have higher failure risks due to mechanical damage than large-diameter, high-pressure pipelines. In addition, the current design approach has been shown to have limited ability to deal with new design parameters, such high steel grades, and unique loading conditions such as frost heave and thaw settlement. The paper shows how these limitations can be addressed by adopting a reliability-based limit states design approach. In this approach, a pipeline is designed to maintain a specified reliability level with respect to its actual expected failure mechanisms (known as limit states). Implementation involves identifying all relevant limit states, selecting target reliability levels that take into account the severity of the failure consequences, and developing a set of design conditions that meet the target reliability levels. The advantages of this approach include lower overall cost for the same safety level, more consistent safety across the range of design parameters, and a built-in ability to address new design situations. Obstacles to its application for onshore pipelines include lack of familiarity with reliability-based approaches and their benefits and lack of consensus on how to define reliability targets. The paper gives an overview of the reliability-based design approach and demonstrates its application using an example involving design for mechanical damage.

scholarly journals Reliability Analysis of Flexible Pavement Using First Order Method

2020 ◽  
pp. 38-54
Author(s):  
Sameh S. Abd El- Fattah ◽  
Ahmed E. Abu El- Maaty ◽  
Ibrahim H. Hashim
Keyword(s):  
Design Methodology ◽  
Flexible Pavement ◽  
Pavement Design ◽  
Design Parameters ◽  
Army Corps ◽  
First Order ◽  
Failure Patterns ◽  
Reliability Method ◽  
Current Design ◽  
The Impact

Flexible pavement design is influenced by many design parameters such as (traffic characterization, pavement depths, structure materials and environmental conditions). To study the impact of variations in design parameters on pavement performance, several attempts have been achieved to add reliability concept to the mechanistic-empirical (M-E) design of pavements. In (M-E) design of pavements, the pavement life depends on subgrade rutting and fatigue cracking, considering them as independent failure patterns. The current design methodology used in many countries such as Egypt is ignoring the impact of temperature variation (despite its importance) on the pavement design. This research aimed to predict the pavement reliability due to variation in pavement design parameters especially temperature using the first-order reliability method (FORM) considering rutting and fatigue failures. Moreover, a comparison was performed between regressions models represented from different pavement agencies to recommend the most efficient one for Egyptian temperature. The results obtained that, considering design parameters variations (without temperature); the reliability based on US Army Corps method (91.64%) was the nearest one to the current design methodology in Egypt (91.0%). After adding temperature variations, the reliability was clearly affected where the regression model of Shell Research agency was the most appropriate one for all Egyptian temperature zones as it achieved the lowest error mean (-0.03) and the lowest error standard deviation (0.0011). Moreover, the air temperature of 28ºC was considered as the inflection point for pavement reliability-temperature curve in Egypt.

Available to meet: advances in professional communications

2020 ◽  
Vol 33 (6) ◽  
pp. 1543-1553
Author(s):  
E. Burton Swanson
Keyword(s):  
Artificial Intelligence ◽  
Social Interaction ◽  
Design Methodology ◽  
Design Approach ◽  
Content Type ◽  
Social Conventions ◽  
Organizational Identities ◽  
Current Design ◽  
The Face ◽  
Industrial Strength

PurposeThis viewpoint paper calls in to question the current design approach to personal artificial intelligence (AI) assistance in support of everyday professional communications, where a bot emulates a human in this role. It aims to stimulate fresh thought among designers and users of this technology. It also calls upon scholars to more widely share incidental insights that arise in their own encounters with such new AI.Design/methodology/approachThe paper employs a case of an email exchange gone wrong to demonstrate the current failings of personal AI assistance in support of professional communications and to yield broader insights into bot design and use. The viewpoint is intended to provoke discussion.FindingsFrom the case, it is indicated that industrial-strength personal AI assistance is not here yet. Designing a personal AI assistant to emulate a human is found to be deeply problematic, in particular. The case illuminates what might be called the problem of blinded agency, in performative contexts where human, robotic and organizational identities are at least partially masked and actions, inactions and intentions can too easily disappear in a thick fog of digital exchange. The problem arises where parties must act in contexts not known to each other, and where who is responsible for what in a mundane exchange is obscured (intentionally or not) by design or by actions (or inactions) of the parties. An insight is that while humans act with a sense of agency to affect outcomes that naturally invoke a corresponding sense of responsibility for what transpires, bots in social interaction simply act and feign responsibility as they have no sense of it beyond their code and data. A personal AI assistant is probably best designed to communicate its artificiality clearly. Missing today are distinctive social conventions for identifying machine agency in everyday interactions as well as an accepted etiquette for AI deployment in these settings.Originality/valueAs a viewpoint contribution, the paper's value is as a stimulant to discussion of alternate approaches to design and use of personal AI assistance in professional communications and where we should be going with this. The presented case of an email exchange gone wrong is simple on the face of it but reveals in its examination a number of complexities and broader insights.

Application of Deterministic and Probabilistic Methods in Pipeline Lateral Buckling Design

2012 ◽  
Author(s):  
Hammam Zeitoun ◽  
Maša Branković ◽  
Edwin Shim ◽  
EuJeen Chin ◽  
Benjamin Anderson
Keyword(s):  
Structural Reliability ◽  
Design Guidelines ◽  
Probabilistic Methods ◽  
Design Solution ◽  
Design Parameters ◽  
Pipeline System ◽  
Limit States ◽  
Lateral Buckling ◽  
Current Design ◽  
Subsea Pipelines

Subsea pipelines lateral buckling design has significantly evolved over the last years as more pipeline projects have moved into more challenging environments and into high temperature / high pressure (HT/HP) design application. Knowledge and understanding of pipeline lateral buckling has improved with design application resulting in refined and enhanced design approaches. Using current design approaches, it is now quite acceptable to control lateral buckle formation along the pipeline by using buckle triggers or to allow uncontrolled lateral buckles, provided that the various design limit states are satisfied. A number of design methodologies can be used to check the acceptability of uncontrolled buckling or to design for controlled buckling including deterministic, probabilistic buckle formation and full Structural Reliability Assessment (SRA) methods. Using SRA or probabilistic methods is usually an attractive design option as lateral buckling design involves dealing with a large number of uncertainties and variation in design parameters. These methods help to ensure the reliability of the proposed buckle initiation scheme. However, the use of these methods is also associated with a number of challenges such as the need to identify key parameters influencing the design and quantifying their uncertainties. Deterministic design approaches on the other hand are simpler to apply. However, they do not provide means to quantify the reliability of the proposed buckling scheme or the design risks. The choice of input parameters in a deterministic design is also relatively subjective which can possibly result in an overly conservative or unconservative design solution depending on the adopted design approach, selected design parameters and pipeline system being considered. Design guidelines and recommended practices such as SAFEBUCK (20) offer comprehensive guidelines to design for lateral buckling. However when faced with a range of complex variables, the designer needs to be aware of the effect of these parameters on the overall design. This paper describes the application of Deterministic and Probabilistic design approaches in lateral buckling design. The paper starts by describing these approaches, their advantages and limitations. The paper then explores a number of key uncertainties and variation in design parameters that the designer is faced with and its effect on the pipeline response.

Design Guidelines for Buildings in Saudi Arabia Considering Energy Conservation Requirements

2014 ◽  
Vol 548-549 ◽  
pp. 1601-1606 ◽  
Author(s):  
Abdullah. M Al-Shaalan ◽  
Wakeel Ahmed ◽  
Abdulhameed Alohaly
Keyword(s):  
Saudi Arabia ◽  
Energy Conservation ◽  
Performance Standards ◽  
Design Guidelines ◽  
Design Parameters ◽  
Kingdom Of Saudi Arabia ◽  
The Past ◽  
Prime Objective ◽  
Conservation Principles ◽  
And Performance

In Kingdom of Saudi Arabia (KSA), the contribution from buildings towards energy consumption, both residential and commercial, has steadily increased reaching figures of 35% to 40% in the past few years. For this reason, energy efficiency in buildings is a prime objective for energy policy at regional, national and international levels. This research aims to provide design guidelines for buildings in Saudi Arabia taking into consideration the energy conservation principles. The proposed design parameters/guidelines are supported by computer simulation results of the software named “eQUEST” (Quick Energy Simulation Tool). This paper specifies minimum thermal resistance for walls and roofs, size and quality for glazing and performance standards for air conditioning (AC) systems.

Application of fuzzy axiomatic design methodology for selection of design alternatives

2015 ◽  
Vol 13 (1) ◽  
pp. 2-22 ◽  
Author(s):  
S. Vinodh ◽  
V. Kamala ◽  
K. Jayakrishna
Keyword(s):  
Design Methodology ◽  
Material Selection ◽  
Axiomatic Design ◽  
Design Approach ◽  
Design Parameters ◽  
Content Type ◽  
Design Alternative ◽  
Design Alternatives ◽  
Practical Feasibility ◽  
Case Organization

Purpose – The purpose of this paper is to report a research conducted to apply fuzzy axiomatic design approach for selecting the design alternatives of an overflow valve. Design/methodology/approach – The approach started with the identification of functional requirements (FRs) and design parameters (DPs) and the relationship between them to select the best design alternative. Fuzzy analytical hierarchy process was used to calculate the weightage of FRs. The independence and information axioms were being deployed to validate the selection process. Findings – The most important FRs being identified include “improve manufacturability and adaptability”, “improve ease of operation” and “provide strength and reliability”. The most important DPs are design unification on washer and outlet valve, material selection for improving the strength and reliability and pressure change to check whether the valve is withstanding the pressure using flow analysis. The best design alternative (A1) which deals with material substitution is being implemented in the case organization. The proposed methodology also enables contemporary design engineers to effectively select the best design among a set of alternatives in a fuzzy environment. Research limitations/implications – This paper presents the application of fuzzy axiomatic design for selecting the best design alternative of an overflow valve. The identified best design is being subjected to implementation in the case organization. Practical implications – The industry decision makers were involved throughout the conduct of the study. Hence, the inferences derived from the study possess practical feasibility. Originality/value – The application of the fuzzy axiomatic design approach for selecting the best design alternative of an overflow valve is the original contribution of the authors. Also, the practical feasibility of the approach is also being exemplified.

scholarly journals BIKED: A Dataset for Computational Bicycle Design with Machine Learning Benchmarks

2021 ◽  
pp. 1-19
Author(s):  
Lyle Regenwetter ◽  
Brent Curry ◽  
Faez Ahmed
Keyword(s):  
Design Space ◽  
Data Driven ◽  
Design Parameters ◽  
Random Generation ◽  
Current Design ◽  
Research Questions ◽  
Class Labels ◽  
Confusion Matrices ◽  
Bicycle Design ◽  
Embedding Methods

Abstract In this paper, we present “BIKED,” a dataset comprised of 4500 individually designed bicycle models sourced from hundreds of designers. We expect BIKED to enable a variety of data-driven design applications for bicycles and support the development of data-driven design methods. The dataset is comprised of a variety of design information including assembly images, component images, numerical design parameters, and class labels. In this paper, we first discuss the processing of the dataset, then highlight some prominent research questions that BIKED can help address. Of these questions, we further explore the following in detail: 1) How can we explore, understand, and visualize the current design space of bicycles and utilize this information? We apply unsupervised embedding methods to study the design space and identify key takeaways from this analysis. 2) When designing bikes using algorithms, under what conditions can machines understand the design of a given bike? We train a multitude of classifiers to understand designs, then examine the behavior of these classifiers through confusion matrices and permutation-based interpretability analysis. 3) Can machines learn to synthesize new bicycle designs by studying existing ones? We test Variational Autoencoders on random generation, interpolation, and extrapolation tasks after training on BIKED data. The dataset and code are available at http://decode.mit.edu/projects/biked/

New Approach of Whole Engine Structural System Design

2014 ◽  
Author(s):  
Masaharu Andoh ◽  
Tatsuhito Honda ◽  
Kikuo Takamatsu
Keyword(s):  
Engine Performance ◽  
Design Approach ◽  
Jet Engines ◽  
Structural System ◽  
New Approach ◽  
Jet Engine ◽  
Conventional Design ◽  
Engine Design ◽  
Current Design ◽  
And Performance

Fuel-efficient jet engines are developed by many companies. In the conventional design approach of a jet engine, many parameters are investigated independently. Consequently, a developed jet engine by this approach meets conventional design criteria but there is still room for improvement of engine performance. In this research, the new design approach of a jet engine that integrates these design objectives is developed and performance of a jet engine is evaluated. The goal is to develop the design approach of a fuel-efficient and robust jet engine. In current design, a jet engine is developed with a focus on not only performance improvement but also robustness. Therefore, Taguchi method is adopted in order to assess robustness. By this method, a jet engine is optimized based on the analysis that minimizes deterioration and variation of SFC. As a result, more efficient engine design is realized with the new design approach that directly deals with SFC.

Guidelines for balancing the flow in extrusion dies: the influence of the material rheology

2018 ◽  
Vol 38 (2) ◽  
pp. 197-211 ◽  
Author(s):  
A. Rajkumar ◽  
L.L. Ferrás ◽  
C. Fernandes ◽  
Olga S. Carneiro ◽  
J. Miguel Nóbrega
Keyword(s):  
Design Methodology ◽  
Numerical Study ◽  
Flow Distribution ◽  
Processing Parameters ◽  
Surrogate Models ◽  
Design Guidelines ◽  
Sensitivity Analyses ◽  
Extrusion Dies ◽  
Balanced Flow ◽  
Improved Design

Abstract In this work we present improved design guidelines to support the die designer activity, when searching for the flow channel geometry that allows the achievement of a balanced flow distribution, in complex profile extrusion dies. The proposed methodology relies on surrogate models, obtained through a detailed and extensive numerical study, carried out with the open source computational library OpenFOAM®, in which an appropriate numerical solver for the problems under study was implemented. The main contribution of this work is to further enlarge the applicability of the simplified design methodology (Rajkumar A, Ferrás LL, Fernandes C, Carneiro OS, Becker M, Nóbrega JM. Int. Polym. Proc. 2017, 32, 58–71.) previously proposed by this group for similar purposes, by considering the effect of processing parameters and material rheology. The sensitivity analyses performed showed that, among the studied parameters, the power-law exponent was the only one that affected the system behavior. Thus, the previous proposed surrogate models were modified to include the effect of this parameter. Verification studies performed for three geometries and different rheological and process parameters evidenced the effectiveness of the proposed simplified design methodology.

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