Shayne Gooch

Standards and Codes

In coming up with a design that meets user needs in the best way possible, tradeoffs must be made amongst the requirements of function, safety, timeliness, cost, ergonomics, the environment, and aesthetics. Established standards and codes help to provide the design engineer with a basis for making judgments such as “how safe is safe enough” in a professionally acceptable manner. The application, interpretation, and development of appropriate standards, codes, and certifications are issues of increasing importance to design engineers, especially with the more global approach to design and manufacture. Not only do the local requirements vary widely from place to place, but also so do user expectations and attitudes concerning the performance of products and equipment. Such factors can create unanticipated delays and additional design costs that are sufficient to jeopardize the future of a complete project, as shown by the example in Hales and Poczynok (2001), especially when combined with cultural and language misunderstandings. This chapter on standards and codes is included simply to highlight a few important issues and to provide a useful list of international contacts for basic information. The massive task of trying to assemble a coherent picture of what standards and codes exist in different countries, and how they all relate to each other, is something that really was not practicable until the Internet became a reality, but now it is possible to get a good overview by visiting the International Organization for Standardization (ISO) Website and those of the various organizations listed. For this reason the list has been updated to include the Website address for each contact, both within the text and electronically on the CD accompanying the book.

Steps Towards Geographically Dispersed Collaborative Student Design Projects

A need exists to teach undergraduate students the skills required for collaborative working in geographically dispersed teams. A program for running collaborative student engineering design projects between the Universities of Bath (United Kingdom) and Canterbury (New Zealand) was implemented in January 2002. This paper presents the approach to collaborative working on this first project. The paper shows that whilst the Universities run on different education programs, and are in different time zones, a path is found for the integration of a collaborative design project within the curriculum of both design courses. The primary forms of communication were email, project web pages and videoconferences. The results of the study provide a basis for further collaborative exchanges between the Universities.Copyright

The dynamics and limits on the scaling of a flexible kinetic sculpture

Abstract Highly flexible structures may be scaled up by different criteria that lead to different degrees of structural integrity as the scale increases. This paper first explores the effects of different scaling rules, focusing in particular on a double-size version of the Len Lye kinetic sculpture Blade, whose aesthetic performance characteristics must be preserved as the size is increased. Stresses in the sculpture increase, reaching first an economic limit beyond which frequent fatigue failure makes the sculpture too costly to operate. As the scale further increases, a size is reached where the sculpture will collapse. A dimensional parameter for comparing the values of the life to failure for different construction materials is also developed. The second part of the paper summarizes the results of different analytical approaches to the dynamics of Blade, both with and without the inclusion of an axial acceleration load due to gravity. The results of analyses are found to be in good agreement with experimental data. The paper closes by discussing some of the design implications of implementing the drive system for a double-size version of Blade that has been built and is now on public display.

The study of the interaction of humans with wheelchairs to improve the design

In order to evaluate a wheelchair design it is necessary to look at the capabilities of the user and the chair’s intended purpose. Whilst some chairs are only required to provide infrequent mobility indoors, others need to enable the user to travel great distances out doors over rough terrain. In this respect the chair should be considered in the same manner as any other ‘inclusive’ product (or be useable by all). There is a need to better understand the capabilities of different users and how this affects their ability to use a wheelchair for the express purpose required. A detailed experimental investigation was carried out into the wheelchair propulsion characteristics of people with paraplegia and tetraplegia. In this investigation, subjects’ posture, applied forces, and their strategies in applying forces to the wheel rims were studied. Three distinct postures and corresponding techniques were observed and subsequently modelled in a constraint-modelling environment. Here rules were developed that allowed these differing postures to be applied to a manikin representation and their effect upon the wheelchair mobility evaluated. From this study the needs for these classes of individuals were identified in order to allow the wheelchairs to be evaluated. Where conflicts existed between the chair and the user, different modifications in both chair and posture were proposed and assessed. Where no simple modifications exist such a study can provide the basis for a more radical and improved design.© 2009 ASME

Using Constraints in the Understanding of the Interactions Between Products and Humans

The acceptability of consumer products often relies upon ease of successful use. Here there is a crossover between the functionality and how the user can derive the actions required. The form of these relationships can encompass the complexity of the physical actions that are required, the experience and capability of the user, and the social context in which the use takes place.

Classification Efficiency in Wheelchair Rugby: Strength Analysis

Abstract This study investigates the arm strength and function of people with tetraplegia, specifically in relation to wheelchair rugby athletes and their in game classification level. Four groups of individuals were assessed; able-bodied participants, individuals with natural triceps function, those with limited or no triceps function, and people who had undergone a deltoid-to-triceps assistive surgery. This research seeks to improve understanding the range of muscle function impairment in people with tetraplegia, and to provide insight into the effects of the deltoid-to-triceps procedure on muscle function. It is hoped that these results will aid in the classification process for wheelchair rugby athletes. 16 athletes were tested, and individual force maps were created demonstrating the magnitude and location of high arm strength areas around the body. Results showed that the able-bodied group reached the highest maximum applied force, followed by natural triceps, no triceps, and then the deltoid-triceps group. The results from the no triceps and deltoid-triceps groups showed areas of overlap, indicating a similar function level. It is recommended that the push test be used to aid athlete assessments along with the wheelchair rugby classification process.

Classification Efficiency in Wheelchair Rugby: Wheelchair Propulsion Power Analysis

Abstract This study determines the ability of people with tetraplegia, specifically wheelchair rugby players, to propel themselves in their rugby wheelchair. The paper makes a comparison between three groups of athletes: those who had undergone a Deltoid - Triceps Transfer (DTT) procedure; those who had some triceps function; and those with no triceps function. It is intended that this analysis will assist in informing current wheelchair classification processes, specifically for those athletes with DTT. A total of 17 athletes were tested and their data analysed using numerical differentiation and modeling to derive a quantitative performance indicator of maximum wheelchair propulsion power. Results showed that the no triceps and DTT groups performed similarly with a mean of 26W and 19W respectively. Both of these groups were under half the power output of the triceps group who achieved a mean propulsion power of 65.5W.

Classification Efficiency in Wheelchair Rugby: Throwing Analysis

Abstract This study analyzed the ability of wheelchair rugby players to complete four commonly used passing techniques. A total of 15 athletes were tested and their data processed using KINOVEA sports performance analysis software and kinematic principles in order to derive quantitative performance indicators such as throw force, power and velocity for each of the passing techniques. Of particular interest to this study were the differences between athletes with and without triceps and those who had Deltoid - Triceps Transfer. The correlation between throwing abilities and current wheelchair rugby classification was also analyzed. Results showed that the entire no triceps group was able to throw using a chest pass and an impact pass; however only one third could perform the overarm passing technique and none were able to perform the sidearm pass technique. This group had an average throw distance of 4.8m. Furthermore, the deltoid-triceps participants were all able to throw a chest pass and an impact pass; however only one half could complete the overarm passing technique and none were able to perform the sidearm pass technique. This group had an average throw distance of 3.5m The group with triceps performed far better overall; with all participants being able to complete all throwing techniques with an average a throw distance of 8m. Finally, as expected, the able-bodied athletes performed the best of the four groups with an average throw distance of 12.3m. The triceps group had an average classification of 2, the no triceps group had an average classification of 0.5 and the deltoid-triceps transfer group had an average classification of 1. These current classifications are a good correlation when compared with the results of this study; except for the deltoid-triceps transfer athletes, who from the results of this study should have the throwing performance of a 0.5 point athlete.

Analysis of a Lever-Driven Wheelchair Prototype and the Correlation between Static Push Force and Wheelchair Performance

Abstract In this experimental study a lever-driven wheelchair prototype was compared with a manual wheelchair. The push force of 13 able-bodied human participants was measured over the range of motion required to propel the lever-driven wheelchair prototype and the standard manual wheelchair. The push force that is required to propel each wheelchair was measured statically using strain gauges and dynamically using a purpose built dynamometer to quantify high and low force areas and to determine if correlation exists to wheelchair performance. The force exerted, simulated peak wheelchair velocity, acceleration, torque and power, were examined. The 13 human participants completed five maximal effort tests in the lever-driven wheelchair and three maximal effort tests in a manual wheelchair on the dynamometer. A multiple regression and a Pearsons product-moment correlation coefficient analysis were performed on the acquired data and a p-value of less than 0.05 level of significance was found; suggesting a correlation does exist between the static and dynamic force measurement methods.

Users and Customers: Design Feedback

Well-designed products tend to be readily accepted and absorbed into general usage, setting the standard until superseded by improved models or a completely new development. The expectations of customers and users change with time, not always in a predictable fashion. Once upon a time it was accepted practice to use a starting handle to hand crank one’s car, and many a sore thumb resulted from hooking it over the handle in the wrong way. In 1912, Cadillac led the way in introducing starter motors. These soon became the norm, and hand-cranking became an annoyance one put up with to get going when the battery “went flat,” which it did with monotonous regularity. Now the expectation is that the car should start at the turn of a key, thousands of times, year after year, without any attention whatsoever. Anyone designing a product must, as a minimum, meet current user expectations or the product will not sell, and the trick is also to try and work out how user expectations will change in the future so as to meet those better than the competition (Cagan and Vogel, 2002). For example, the concern for product quality, product safety, and environmental issues is likely to increase steadily, so design engineers must continually improve their knowledge and skills in these areas.