Exploration of Alternatives for Prestressed Concrete Monoblock Crosstie Design Based on Flexural Capacity

2015 ◽  
Author(s):  
Matthew V. Csenge ◽  
Henry E. Wolf ◽  
Marcus S. Dersch ◽  
J. Riley Edwards ◽  
Ryan G. Kernes ◽  
...  
Keyword(s):  
Prestressed Concrete ◽  
Theoretical Calculations ◽  
Design Parameters ◽  
Similar Amount ◽  
Flexural Capacity ◽  
Track Geometry ◽  
Critical Design ◽  
Load Carrying ◽  
Potential Benefits ◽  
And Performance

Recent North American railway trends signify a transition to increased axle loads and higher train speeds. The use of concrete crossties is common practice in these applications for a variety of reasons, including higher load-carrying capacity and improved ability to maintain proper track geometry. Currently, prestressed concrete monoblock crossties share many geometric and structural properties regardless of manufacturer. For multiple reasons, some manufacturers are investigating the potential benefits of new geometries for crosstie design. One alternative currently being explored is to modify the length and cross-section of the crosstie in order to increase the flexural capacity while using a similar amount of material. In this paper the benefits and implications of these changes will be explored both through theoretical calculations and laboratory testing. This alternative design will be evaluated and compared to concrete crossties representative of those currently found in North America. Comparison of the designs will be based on structural cracking at critical locations along the crosstie. These results were used to provide guidance on critical design parameters for concrete crossties capable of withstanding future loading and performance demands.

Friction-Induced Dynamics of Axially-Moving Media in Contact With an Actively-Positioned Surface

2008 ◽  
Author(s):  
V. Kartik ◽  
Evangelos Eleftheriou
Keyword(s):  
Data Storage ◽  
Surface Friction ◽  
Design Parameters ◽  
Moving Medium ◽  
Critical Design ◽  
Flexible Material ◽  
Potential Benefits ◽  
Axially Moving ◽  
The Stability ◽  
Moving Media

The dynamics of an axially-moving flexible medium are examined in the context of an application where the medium is partially supported by a frictional surface, that actively-orients itself relative to the direction of transport. The stability and motion of the medium are of interest in a magnetic tape data storage application where the orientation of a sensing surface is continuously altered in order to ‘follow’ the medium’s motion. Moving media that are in contact with such guiding surfaces experience friction excitations induced by the relative motion in addition to what is observed with a stationary guiding surface. Friction-induced bending moments, as well as tension fluctuation beyond the permissible limits for the flexible material can erode the potential benefits of such active positioning. This paper describes some of these dynamic phenomena using the simplified example of a planar guiding surface whose orientation is dynamically altered relative to the moving medium. A physical model for the friction-induced excitation of the moving medium is developed, and the dynamics are analyzed for their effect on critical design parameters such as the achievable bandwidth of the active control algorithm, as well as with respect to constraints on the geometry and positioning of the guiding surface.

scholarly journals A modular design method based on TRIZ and AD and its application to cutter changing robot

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110343
Author(s):  
Mei Yang ◽  
Yimin Xia ◽  
Lianhui Jia ◽  
Dujuan Wang ◽  
Zhiyong Ji
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Idea Generation ◽  
Design Parameters ◽  
Problem Analysis ◽  
Concept Design ◽  
Functional Requirements ◽  
Shield Tunneling ◽  
Structural Hierarchy ◽  
And Performance

Modular design, Axiomatic design (AD) and Theory of inventive problem solving (TRIZ) have been increasingly popularized in concept design of modern mechanical product. Each method has their own advantages and drawbacks. The benefit of modular design is reducing the product design period, and AD has the capability of problem analysis, while TRIZ’s expertise is innovative idea generation. According to the complementarity of these three approaches, an innovative and systematic methodology is proposed to design big complex mechanical system. Firstly, the module partition is executed based on scenario decomposition. Then, the behavior attributes of modules are listed to find the design contradiction, including motion form, spatial constraints, and performance requirements. TRIZ tools are employed to deal with the contradictions between behavior attributes. The decomposition and mapping of functional requirements and design parameters are carried out to construct the structural hierarchy of each module. Then, modules are integrated considering the connections between each other. Finally, the operation steps in application scenario are designed in temporal and spatial dimensions. Design of cutter changing robot for shield tunneling machine is taken as an example to validate the feasibility and effectiveness of the proposed method.

scholarly journals Food Choice Decisions of Collegiate Division I Athletes: A Qualitative Exploratory Study

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2322
Author(s):  
Kaitlyn M. Eck ◽  
Carol Byrd-Bredbenner
Keyword(s):  
Health Beliefs ◽  
Fast Food ◽  
Division I ◽  
Iron Protein ◽  
Food And Nutrition ◽  
Fried Foods ◽  
Potential Benefits ◽  
And Performance ◽  
Division I Athletes ◽  
Nutrition Professionals

Limited research has examined athletes’ food and health beliefs and decisions and the congruence of these decisions with recommendations from nutrition professionals. This study aimed to improve understanding of athletes’ food-related beliefs and practices to enable nutrition professionals to more effectively enhance performance while protecting athletes’ health. Division I college athletes (n = 14, 64% female) from a variety of sports were recruited to participate in 20-min semi-structured phone interviews about food and nutrition-related behaviors and cognitions. Data were content analyzed to identify themes and trends. Prominent factors influencing athletes’ food choices were potential benefits to health and performance, availability of foods, and recommendations from sports dietitians. Foods commonly consumed by athletes, including fruits, vegetables, and lean protein, were generally healthy and aligned with sports nutrition recommendations. Athletes avoided energy-dense nutrient-poor foods, such as fast food and fried foods, with the goal of improving performance. Some athletes took supplements (i.e., multivitamin, iron, protein) on the premise that they would improve health and enhance performance or recovery. While athletes’ nutrition behaviors are generally congruent with current recommendations, findings highlighted misconceptions held by athletes related to the benefits of some supplements and the belief that packaged/processed foods were inherently less healthy than other options. Nutrition misconceptions held by athletes and incongruities between athletes’ nutrition knowledge and behaviors suggest that dietitians should aim to dispel misconceptions held by athletes and provide additional guidance and information to support athletes’ current healthful behaviors to ensure these behaviors extend beyond their college athletic career.

scholarly journals Selected implications of a hyper-connected world on pavement engineering

2020 ◽  
Vol 13 (6) ◽  
pp. 673-678
Author(s):  
Wynand Jacobus van der Merwe Steyn
Keyword(s):  
Data Science ◽  
Industrial Revolution ◽  
Cost Benefit ◽  
Physical World ◽  
Management Systems ◽  
Life Data ◽  
Pavement Engineering ◽  
Potential Benefits ◽  
And Performance ◽  
Lifecycle Management

AbstractThe world is becoming a hyper-connected environment where an abundance of data from sensor networks can provide continuous information on the behaviour and performance of infrastructure. The last part of the 3rd Industrial Revolution (IR) and the start of the 4th IR gave rise to a world where this overabundance of sensors, and availability of wireless networks enables connections between people and infrastructure that was not practically comprehensible during the 20th century. 4IR supports the datafication of life, data science, big data, transportation evolution, optimization of logistic and supply chains and automation of various aspects of life, including vehicles and road infrastructure. The hyper-connected 4IR environment allows integration between the physical world and digital and intelligent engineering, increasingly serving as the primary lifecycle management systems for engineering practitioners. With this background, the paper evaluates a few concepts of the hyper-connected pavement environment in a 4IR Digital Twin mode, with the emphasis on selected applications, implications, benefits and limitations. The hyper-connected world can and should be managed in the pavement realm to ensure that adequate and applicable data are collected regarding infrastructure, environment and users to enable a more efficient and effective transportation system. In this regard, and planning for future scenarios where the proliferation of data is a given, it is important that pavement engineers understand what is possible, evaluate the potential benefits, conduct cost/benefit evaluations, and implement appropriate solutions to ensure longevity and safety of pavement infrastructure.

scholarly journals Soft Spherical Tensegrity Robot Design Using Rod-Centered Actuation and Control

2016 ◽  
Author(s):  
Lee-Huang Chen ◽  
Kyunam Kim ◽  
Ellande Tang ◽  
Kevin Li ◽  
Richard House ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Space Exploration ◽  
Robot Design ◽  
The Novel ◽  
Flexible Design ◽  
Spherical Robot ◽  
Potential Benefits ◽  
And Performance ◽  
And Control

This paper presents the design, analysis and testing of a fully actuated modular spherical tensegrity robot for co-robotic and space exploration applications. Robots built from tensegrity structures (composed of pure tensile and compression elements) have many potential benefits including high robustness through redundancy, many degrees of freedom in movement and flexible design. However to fully take advantage of these properties a significant fraction of the tensile elements should be active, leading to a potential increase in complexity, messy cable and power routing systems and increased design difficulty. Here we describe an elegant solution to a fully actuated tensegrity robot: The TT-3 (version 3) tensegrity robot, developed at UC Berkeley, in collaboration with NASA Ames, is a lightweight, low cost, modular, and rapidly prototyped spherical tensegrity robot. This robot is based on a ball-shaped six-bar tensegrity structure and features a unique modular rod-centered distributed actuation and control architecture. This paper presents the novel mechanism design, architecture and simulations of TT-3, the first untethered, fully actuated cable-driven six-bar tensegrity spherical robot ever built and tested for mobility. Furthermore, this paper discusses the controls and preliminary testing performed to observe the system’s behavior and performance.

Full scale test of a PC bridge to calibrate assessment methods

2021 ◽  
Author(s):  
Niklas Bagge ◽  
Jonny Nilimaa ◽  
Silvia Sarmiento ◽  
Arto Puurula ◽  
Jaime Gonzalez-Libreros ◽  
...  
Keyword(s):  
Prestressed Concrete ◽  
Structural Response ◽  
Sensitivity Study ◽  
Assessment Method ◽  
Full Scale ◽  
Concrete Bridges ◽  
Fractional Factorial ◽  
Fe Model ◽  
Load Carrying ◽  
Existing Bridges

<p>In this paper, experiences on the development of an assessment method for existing bridges are presented. The method is calibrated using the results of full-scale testing to failure of a prestressed bridge in Sweden. To evaluate the key parameters for the structural response, measured by deflections, strains in tendons and stirrups and crack openings, a sensitivity study based on the concept of fractional factorial design is incorporated to the assessment. Results showed that the most significant parameters are related to the tensile properties of the concrete (tensile strength and fracture energy) and the boundary conditions. A finite element (FE) model in which the results of the sensitivity analysis were applied, was able to predict accurately the load-carrying capacity of the bridge and its failure mode. Two additional existing prestressed concrete bridges, that will be used to improve further the method, are also described, and discussed.</p>

Constructed wetlands in UK urban surface drainage systems

2005 ◽  
Vol 51 (9) ◽  
pp. 31-37 ◽  
Author(s):  
B. Shutes ◽  
J.B. Ellis ◽  
D.M. Revitt ◽  
L.N.L. Scholes
Keyword(s):  
Constructed Wetlands ◽  
Design Criteria ◽  
Road Runoff ◽  
Agenda 21 ◽  
Drainage Systems ◽  
Potential Benefits ◽  
Guidance Documents ◽  
Environment Agency ◽  
And Performance ◽  
The Uk

This paper presents the outcome of an inventory of planted wetland systems in the UK which are classified according to land use type and are all examples of sustainable drainage systems. The introduction of constructed wetlands to treat surface runoff essentially followed a 1997 Environment Agency for England and Wales report advocating the use of “soft engineered” facilities including wetlands in the context of sustainable development and Agenda 21. Subsequently published reports by the UK Construction Industry Research and Information Association (CIRIA) have promoted the potential benefits to both developer and the community of adopting constructed wetlands and other vegetated systems as a sustainable drainage approach. In addition, the UK Environment Agency and Highways Agency (HA) have recently published their own design criteria and requirements for vegetative control and treatment of road runoff. A case study of the design and performance of a constructed wetland system for the treatment of road runoff is discussed. The performance of these systems will be assessed in terms of their design criteria, runoff loadings as well as vegetation and structure maintenance procedures. The differing design approaches in guidance documents published in the UK by the Environment Agency, CIRIA and HA will also be evaluated.

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