MECHANICAL TESTING OF FUSED FILAMENT 3-D PRINTED COMPONENTS FOR DISTRIBUTED MANUFACTURING

Fused filament fabrication (FFF)-based open-source 3-D printers offer the potential of decentralized manufacturing both in developing and developed countries. Unfortunately, a severe lack of data and standards relating to material properties and printed components limit this potential. This thesis first investigates the mechanical properties of a wide-range of FFF materials and provides a database of mechanical strength of the materials tested. The results demonstrate that the tensile strength of a 3-D printed specimen depends largely on the mass of the specimen, which provides a means to estimate the strength of 3-D printed components. Then this information is used to evaluate a bicycled pedal, which was 3-D printed and tested following the CEN (European Committee for Standardization) standards for racing bicycles. The results show the pedals meet the CEN standards and can be used on bicycles at lower costs than standard pedals. This investigation indicates the viability of distributed manufacturing

Cycling Through History: Making an American Sport 1880-present, Blog 3

Student blog posts from the Great VCU Bike Race Book

Barriers and facilitators to public bicycle scheme use: A qualitative approach

The purpose of this study was to explore barriers and facilitators to using CityCycle, a public bicycle share scheme in Brisbane, Australia. Focus groups were conducted with participants belonging to one of three categories. Group one consisted of infrequent and noncyclists (no bicycle riding over the past month), group two were regular bicycle riders (ridden a bicycle at least once in the past month) and group three was composed of CityCycle members. A thematic analytic method was used to analyse the data. Three main themes were found: Accessibility/spontaneity, safety and weather/topography. The lengthy sign-up process was thought to stifle the spontaneity typically thought to attract people to public bike share. Mandatory helmet legislation was thought to reduce spontaneous use. Safety was a major concern for all groups and this included a perceived lack of suitable bicycle infrastructure, as well as regular riders describing a negative attitude of some car drivers. Interestingly, CityCycle riders unanimously perceived car driver attitudes to improve when on CityCycle bicycles relative to riding on personal bicycles. Conclusions: In order to increase the popularity of the CityCycle scheme, the results of this study suggest that a more accessible, spontaneous sign-up process is required, 24/7 opening hours, and greater incentives to sign up new members and casual users, as seeing people using CityCycle appears critical to further take up

On the influence of tyre and structural properties on the stability of bicycles

In recent years the Whipple Carvallo Bicycle Model has been extended to analyse high speed stability of bicycles. Various researchers have developed models taking into account the effects of front frame compliance and tyre properties, nonetheless, a systematic analysis has not been yet carried out. This paper aims at analysing parametrically the influence of front frame compliance and tyre properties on the open loop stability of bicycles. Some indexes based on the eigenvalues of the dynamic system are defined to evaluate quantitatively bicycle stability. The parametric analysis is carried out with a factorial design approach to determine the most influential parameters. A commuting and a racing bicycle are considered and numerical results show different effects of the various parameters on each bicycle. In the commuting bicycle, the tyre properties have greater influence than front frame compliance, and the weave mode has the main effect on stability. Conversely, in the racing bicycle, the front frame compliance parameters have greater influence than tyre properties, and the wobble mode has the main effect on stability

Perceptions of Bicycle-Friendly Policy Impacts on Accessibility to Transit Services: The First and Last Mile Bridge, MTI Report 12-10

The coordination of bicycle and transit modes has received close attention from public transit planners and researchers in recent years, as transit agencies around the world have installed bicycle racks on transit vehicles, implemented bicycles-on-trains policies, and made other efforts to facilitate bicycle-transit integration. Many planners presume that the catchment area for transit is enlarged by these efforts, but geographic changes in the size of catchment areas have not been effectively documented. This research project was designed to assess the distances travelled on bicycle by cycle-transit users (CTUs), both those who use bicycles as a means of access to transit stops and stations and those who bicycle to and travel on transit with their bicycles. A mixed-methods approach was employed, using a literature review, a survey of cyclist-transit users in Philadelphia and San Francisco, and telephone interviews with a subset of survey respondents. Responses provided by CTUs in the two cities allow us to define their characteristics and behaviors in detail. What is more, they highlight two intriguing conclusions: that transit catchment areas can be much larger for cycle-transit users than for traditional transit users who access transit buses and rail on foot, and that the very concept of a cycle-transit catchment area is quite complex because of the variety of travel opportunities that cycle-transit coordination policies present transit riders. CTUs take advantage of larger catchment areas to reduce their travel costs, and they use those catchment areas in curious, less predictable and more varied ways

Simulation of a public e-bike sharing system

Urban areas are in need of efficient and sustainable mobility service and it seems that one of the options that arouses more interest are public bicycles systems, which in the last decade have been promoted in cities all over the world almost exponentially, surpassing the 500 bike-sharing programs worldwide. This has resulted in a continuous evolution of these systems, which, due to their recent appearance, have practically gone ahead of the works focused on their study. This thesis intends to develop an agent-based simulation model to emulate a bikesharing system, in order to allow the optimization of the main strategic and tactical system variables, such as the total number of bicycles, the number of reposition equipment, the size of the stations and the occupancy after being repositioned, that is, its balanced occupancy. The model will be applied and validated with the parameter values of the system currently applied in Barcelona and an improved scenario will be posed to analyze the performance of a better hypothetical solution for balanced occupancy as an example of the simulator potential. The simulation is coded in Matlab® environment, using the paradigm of Object Oriented Programming, which aims to ease its use, understanding and expansion, following the open-source philosophy, which has proliferated in recent years. The document contains the description of the model and the performance of the program, its structure, and its validation. In addition, the source code can be found attached for its free download and use

Cycling Through History: Making an American Sport 1880-present, Blog 2

Student blog posts from the Great VCU Bike Race Book

Campus Mobility for the Future: The Electric Bicycle

Sustainable and practical personal mobility solutions for campus environments have traditionally revolved around the use of bicycles, or provision of pedestrian facilities. However many campus environments also experience traffic congestion, parking difficulties and pollution from fossil-fuelled vehicles. It appears that pedal power alone has not been sufficient to supplant the use of petrol and diesel vehicles to date, and therefore it is opportune to investigate both the reasons behind the continual use of environmentally unfriendly transport, and consider potential solutions. This paper presents the results from a year-long study into electric bicycle effectiveness for a large tropical campus, identifying barriers to bicycle use that can be overcome through the availability of public use electric bicycles