bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Assistive Device Design to Implement Cornerstone Design in a Junior Level Machine Design II Course
Authors: Reffeor Wendy S. 
Published: January 2015

Assistive device design was used in a Junior level Machine Design II course to reinforce design concepts while increasing student awareness of the specialized needs of individual product users. Since these projects addressed the needs of specific users and/or a group of specific users, they were externally funded. This provided an incentive for student groups to accomplish the task assigned with a greater level of attention to detail and need to satisfy the design constraints. In all cases, student teams provided a useable, deliverable device to the customer at the end of the semester. A survey of the customers was completed at the end of the semester to determine customer satisfaction with the process. Overall, customers were highly satisfied with the results, although many expressed frustration due to the project timeline being too long.
In all cases, a useable product was delivered at the end of the project. However, improvements were also possible in all cases and further work will be done on the products to better align them with user needs.
Student response to the project was as expected. The students felt this project was a very valuable learning experience and reinforced not only the course material, but also forced them to learn about technologies not discussed in class. However, many commented that the time required to complete the project as well as the traditional course work was far greater than the time required of their peers taking the course with a “paper” project.
Expanding VRPN to Tasks in Virtual Engineering
Authors: Stelzer Ralph , Steindecker Erik , Arndt Stephan , Steger Wolfgang 
Published: January 2015

A high variety of peripherals for the interaction between human and computer is available (e.g. Mouse, Touch and Camera). Therefore the peripherals communicate in different ways with the computer and its applications. The library VRPN is a common, generalized interface between peripherals and VR applications to reduce the development effort. Its main advantages are the system independent client-server architecture with real-time capability and the easy implementation of new peripheral devices.
The proposed paper describes the adaption and extension of the VRPN concept to address the challenges of engineering like modeling, evaluation, simulation and modification. Innovative interaction devices have the capability to enhance engineering applications with comparatively small effort but great benefit. As an example a VRPN client is implemented into the CAD application SolidWorks. This enables the use of any interaction device which is supported by VRPN. For example, the designer can control the model view by human movement via tracking device like the Microsoft Kinect or the Geomagic Touch.
The data transfer can be either established in a synchronous or in an asynchronous manner. Regarding synchronous transfer, the server-client architecture was implemented in different applications (e.g. CAD, VR). In order to realize a time shifted asynchronous transfer a recorder-player middleware was developed.
On Some Problems With Modeling of Coulomb Friction in Self-Locking Speed Reducers
Authors: Wojtyra Marek 
Published: January 2015

A simple mathematical model of friction in speed reducers is presented and discussed. A rigid body approach, typical for multibody simulations, is adopted. The model is based on the Coulomb friction law and exploits the analogy between reducers and wedge mechanisms.
The first version of the model is purely rigid, i.e. no deflections of the mechanism bodies are allowed. Constraints are introduced to maintain the ratio between input and output velocity. It is shown that when friction is above the self-locking limit, paradoxical situations may be observed when kinetic friction is investigated. For some sets of parameters of the mechanism (gearing ratio, coefficient of friction and inertial parameters) two distinct solutions of normal and friction forces can be found. Moreover, for some combinations of external loads, a solution that satisfies equations of motion, constraints and Coulomb friction law does not exist. Furthermore, for appropriately chosen loads and parameters of the mechanism, infinitely many feasible sets of normal and friction forces can be found. Examples of all indicated paradoxical situations are provided and discussed.
The second version of the model allows deflection of the frictional contact surface, and forces proportional to this deflection are applied to contacting bodies (no constraints to maintain the input-output velocity ratio are introduced). In non-paradoxical situations the obtained results are closely similar to those predicted by the rigid body model. In previously paradoxical situations no multiple solutions of friction force are found, however, the amended model does not solve all problems. It is shown that in regions for which the paradoxes were observed only unstable solutions are available. Numerical examples showing behavior of the model are provided and analyzed.
An Optimized Kinematic Mobility Analysis of Protein Molecules
Authors: Demirtas Ahmet , Shahbazi Zahra 
Published: January 2015

Understanding the 3D structure and consequently the motion of protein molecules contributes to simulate their function. Modeling protein molecules as kinematic chains has been used to predict protein molecules flexible and rigid regions as well as their degrees of freedom to predict their mobility. However, high computational cost for relatively large molecules is one of the major challenges in this field.
In this paper we have combined our previously developed rigidity analysis (ProtoFold) with pebble game thus improving computational cost of our simulation. Here, we have determined the required time for all steps of ProtoFold and subsequently the most time consuming step. Results have shown that finding rigid loops inside the protein structure using graph theory and Grübler-Kutzbach criterion is the slowest part of the procedure, taking an average of 75% of the time required for the rigidity analysis. Therefore we have replaced this step with pebble game. The modified method has been applied to a random group of protein molecules and its efficiency in significantly improving the simulation speed has been verified.
Development of a Test Bench for the Subjective and Objective Evaluation of the Vibrational Comfort of Bicycle Components
Authors: Petrone Nicola , Trabacchin Francesco 
Published: January 2015

Vibrational comfort is one of the most important parameters evaluated by cyclists and it is correlated to the response of bicycle components in combination with the cyclist’s characteristics.
Vibration transmissibility of wheels and saddles had been recently studied during lab tests using a wooden dummy bottom resting on the saddle and in road tests on an instrumented racing bicycle at different speeds on different surfaces.
In this study, a test bench was developed in order to simulate different vibrational inputs to the seatpost from the road surface on a group of real cyclists during steady cycling. The bench is composed by a racing bicycle without wheels, hinged at the front fork axle and sustained by an hydraulic actuator connected to the seatpost. The bicycle is equipped with pedals and chain wheel and a long chain drives another rear wheel fixed to the bench and connected to brake rollers.
Three racing bicycle saddles were evaluated by a group of five cyclists after the application of vibrational spectra corresponding to PSDs recorded in the field tests: the magnitude of the transfer function H between the input vertical acceleration at the seatpost and the output acceleration at the pelvis was obtained by two accelerometers. The cyclists were in the meantime asked to fill a questionnaire regarding the perceived comfort of the three saddles during the tests.
Initial results showed an encouraging correlation of the subjective ranking of saddles with the corresponding Index of Transmissibility derived from the transfer function H.
An Empirical Study of Information Exchange and Design Support in Product Family Development
Authors: Lundin Michael , Lejon Erik , Dagman Andreas , Näsström Mats , Jeppsson Peter 
Published: January 2015

An investigation carried out at a Swedish manufacturing company has focused specifically on information exchange and design support in and between activities in the company’s product family development process. The process allows, within a defined product family, automated generation of 3D models, product specifications, and a complete foundation for subsequent manufacture and verification.
The core contributions of this paper are the investigation performed, a set of identified challenges which relate to the complexity of everyday decisions made in product family development, how these challenges can be approached and a set of tools exemplifying that approach.
The study indicates that there are limitations in terms of motivation, resources and support for insight, understanding and consequent consideration to downstream implications of design decisions made. The question is whether tools and methods, which are integral aspects of the process already, might serve to further illuminate the process, maximize purposeful support and thereby minimize the efforts required to better consider downstream implications of decisions made. It is the opinion of the authors that it can, and the set of tools for information exchange and design support presented in this paper serves to exemplify how.
Effects of Prosthesis Mass on Hip Energetics, Prosthetic Knee Torque, and Prosthetic Knee Stiffness and Damping Parameters Required for Transfemoral Amputees to Walk With Normative Kinematics
Authors: Narang Yashraj S. , Winter Amos G. 
Published: January 2015

We quantify how the hip energetics and knee torque required for an above-knee prosthesis user to walk with the kinematics of able-bodied humans vary with the inertial properties of the prosthesis. We also select and optimize passive mechanical components for a prosthetic knee to accurately reproduce the required knee torque.
Previous theoretical studies have typically investigated the effects of prosthesis inertial properties on energetic parameters by modifying both mass and mass distribution of the prosthesis and computing kinetic and energetic parameters only during swing. Using inverse dynamics, we determined the effects of independently modifying mass and mass distribution of the prosthesis, and we computed parameters during both stance and swing. Results showed that reducing prosthesis mass significantly affected hip energetics, whereas reducing mass distribution did not. Reducing prosthesis mass to 25% of the mass of a physiological leg decreased peak stance hip power by 26%, average swing hip power by 74%, and absolute hip work over the gait cycle by 22%.
Previous studies have also typically optimized prosthetic knee components to reproduce the knee torque generated by able-bodied humans walking with normative kinematics. However, because the prosthetic leg of an above-knee prosthesis user weighs significantly less than a physiological leg, the knee torque required for above-knee prosthesis users to walk with these kinematics may be significantly different. Again using inverse dynamics, it was found that changes in prosthesis mass and mass distribution significantly affected this required torque. Reducing the mass of the prosthesis to 25% of the mass of the physiological leg increased peak stance torque by 43% and decreased peak swing torque by 76%.
The knee power required for an above-knee prosthesis user to walk with the kinematics of able-bodied humans was analyzed to select passive mechanical components for the prosthetic knee. The coefficients of the components were then optimized to replicate the torque required to walk with the kinematics of able-bodied humans. A prosthetic knee containing a single linear spring and two constant-force dampers was found to accurately replicate the targeted torque (R2=0.90 for a typical prosthesis). Optimal spring coefficients were found to be relatively insensitive to mass alterations of the prosthetic leg, but optimal damping coefficients were sensitive. In particular, as the masses of the segments of the prosthetic leg were altered between 25% and 100% of able-bodied values, the optimal damping coefficient of the second damper varied by 330%, with foot mass alterations having the greatest effect on its value.
Aerodynamic Design of Flat Delta Kite Based on Polhamus Concept of Leading Edge Suction Analogy
Authors: Madduri Bharath , Borazjani Iman 
Published: January 2015

The primary objective of this paper is to design an aerodynamically efficient delta kite that can balance a given load when subjected to aerodynamic loads at a specific angle of attack (α) and altitude (h). The aerodynamic forces calculated based on the potential theory heavily underestimate the forces because of the formation of leading edge vortices on the delta shaped kite. The leading edge vortices are the flow separations caused at the sharp leading edge even for very small angles of attack, which remain attached to the leading edge while the kutta condition is still satisfied at the trailing edge.
Vortex lift and induced drag due to the leading edge vortices are calculated using the Polhamus method. Aerodynamic loads (L and D) have been computed by determining proportionality constants (kp, kv) using the standard Multhopp lifting surface theory (MLST). The variation of (CL) and (ΔCD) for delta kites with aspect ratio A=1, 1.5 and 2 has been examined and validated by comparing the computed CL and ΔCD values to experimental measurements. A set of vertical and horizontal loads (WT,HT) that can be balanced by delta kite at operational heights h=140, 150 and 160 m and α=8° has been successfully determined using this method. The method will be applied for the design and control of a delta kite, which will be used to harvest wind energy at high altitudes.
Solving Structure for Network-Decomposed Problems Optimized With Augmented Lagrangian Coordination
Authors: Xu Meng , Fadel Georges , Wiecek Margaret M. 
Published: January 2015

The complexity of design and optimization tasks of modern products which cannot be carried out by a single expert or by a single design team motivated the development of the field of decomposition-based optimization. In general, the process of decomposition-based optimization consists of two procedures: (1) Partitioning the original problem into sub-problems according to the design disciplines, components or other aspects; and (2) Coordinating these sub-problems to guarantee that the aggregation of their optimal solutions results in a feasible and optimal solution for the original problem. Much current work focuses on alternative approaches for these two procedures.
For a decomposed problem with a hierarchical structure, the above two procedures work very well and the Analytical Target Cascading method tailored for this type of problems can be used as the coordination method. However, for a more generally decomposed problem with a non-hierarchical structure, there are several factors that might affect the performance of the optimization by decomposition besides the traditional two procedures. In this paper, these factors are identified as: (1) the number of Lagrangian multipliers; (2) the number of decomposition levels (3) the existence and the selection of the master sub-problem. These factors further characterize the structure to solve the decomposed problem: the Solving Structure for decomposition-based optimization. Both mathematical and engineering test problems are used to explore the role of the solving structure. The results show that under the same partition and using the same coordination method, the Augmented Lagrangian Coordination, the performance of the decomposition-based optimization may be largely different in terms of efficiency, accuracy and resource cost. The results highlight the importance of choosing an optimal solving structure after deciding on the procedures of partitioning and coordination. Based on these test results, several suggestions for guidelines on the selection of an optimal solving structure selection are proposed.
Automated Generation of Linkage Loop Equations for Planar 1-DoF Linkages, Demonstrated up to 8-Bar
Authors: Parrish Brian E. , McCarthy J. Michael , Eppstein David 
Published: January 2015

In this paper we present an algorithm that automatically creates the linkage loop equations for planar 1-DoF linkages of any topology with rotating joints, demonstrated up to 8-bars. The algorithm derives the linkage loop equations from the linkage graph by establishing a cycle basis through a single common edge. Divergent and convergent loops are identified and used to establish the fixed angles of the ternary and higher links.
Results demonstrate the automated generation of the linkage loop equations for the five distinct 6-bar mechanisms, Watt I-II and Stephenson I-III, as well as the seventy one distinct 8-bar mechanisms.
The resulting loop equations enable the automatic derivation of the Dixon determinant for linkage kinematic analysis of the position of every possible assembly configuration. The loop equations also enable the automatic derivation of the Jacobian for singularity evaluation and tracking of a particular assembly configuration over the desired range of input angles.
The methodology provides the foundation for the automated configuration analysis of every topology and every assembly configuration of 1-DoF linkages with rotating joints up to 8-bar. The methodology also provides a foundation for automated configuration analysis of 10-bar and higher linkages.
Towards Extracting Affordances From Online Consumer Product Reviews
Authors: Chou Amanda , Shu L. H. 
Published: January 2015

We examined online product reviews as a source of novel affordances. Certain affordances may only be discovered through extended use across various environments. User-generated reviews may thus contain unique insights. We analyzed online consumer product reviews from Canadian Tire, one of Canada’s largest retailers. We determined properties of this collection of reviews and commonalities between valuable reviews. In addition to typical challenges associated with natural-language processing, e.g. word-sense disambiguation, we identify characteristics of online consumer reviews that create additional challenges. These challenges include the use of ‘wild English’ and sarcasm in online reviews.
We first present criteria to define and more objectively identify novel affordances from review content. Next, k-means clustering reveals that a combination of syntactical features and high frequency word percentages can separate descriptive from non-descriptive review content. Finally, we identified cue phrases that may indicate higher likelihood of affordance content in a review. Despite existing obstacles, the substantial volume of available online product reviews has potential to become a valuable source of affordances and feedback for designers and retailers alike.
Effects of Abstraction on Selecting Relevant Biological Phenomena for Biomimetic Design
Authors: Feng Tao , Cheong Hyunmin , Shu L. H. 
Published: January 2015

The natural-language approach to identifying biological analogies exploits the existing format of much biological knowledge, beyond databases created for biomimetic design. However, designers may need to select analogies from search results, during which biases may exist towards: specific words in descriptions of biological phenomena, familiar organisms and scales, and strategies that match preconceived solutions.
Therefore, we conducted two experiments to study the effect of abstraction on overcoming these biases and selecting biological phenomena based on analogical similarities. Abstraction in our experiments involved replacing biological nouns with hypernyms. The first experiment asked novice designers to choose between a phenomenon suggesting a highly useful strategy for solving a given problem, and another suggesting a less-useful strategy, but featuring bias elements. The second experiment asked novice designers to evaluate the relevance of two biological phenomena that suggest similarly useful strategies to solve a given problem.
Neither experiment demonstrated the anticipated benefits of abstraction. Instead, our abstraction led to: 1) novice designers associating non-abstracted words to design problems and 2) increased difficulty in understanding descriptions of biological phenomena. We recommend investigating other ways in which abstraction can be implemented when designing similar tools or techniques that aim to support biomimetic design and other design-by-analogy work.
Analogy Seeded Mind-Maps: Testing of a New Design-by-Analogy Tool
Authors: Marshall K. Scott , Crawford Richard , Green Matthew , Jensen Daniel 
Published: January 2015

Recent research has investigated methods based on design-by-analogy meant to enhance concept generation. This paper presents Analogy Seeded Mind-Maps, a new method to prompt generation of analogous solution principles drawn from multiple analogical domains.
The method was evaluated in two separate design studies using senior engineering students. The method begins with identifying a primary functional design requirement such as “eject part.” We used this functional requirement “seed” to generate a WordTree of grammatically analogical words for each design team. We randomly selected a set of words from each WordTree list with varying lexical “distances” from the seed word, and used them to populate the first-level nodes of a mind-map, with the functional requirement seed as the central hub. Design team members first used the word list to individually generate solutions and then performed team concept generation using the analogically seeded mind-map. Quantity and uniqueness of the resulting verbal solution principles were evaluated. The solution principles were further analyzed to determine if the lexical “distance” from the seed word had an effect on the evaluated design metrics. The results of this study show Analogy Seeded Mind-Maps to be useful tool in generating analogous solutions for engineering design problems.
Condition Monitoring and Diagnostics of Wind Turbines: A Survey
Authors: Pennacchi Paolo , Borghesani Pietro , Chatterton Steven , Gultekin Candas 
Published: January 2015

Wind energy conversion is the fastest growing source of electricity generation in the world among the other renewable energy production technologies. Whereas investment costs have decreased over years, operational and maintenance costs of wind turbines are still high, thus attracting the focus of researchers and industrial operators.
Classical maintenance techniques, i.e.: run-to-failure and scheduled-preventive maintenance, are still dominant in this sector; however, condition monitoring has gained space in the wind turbine market and new diagnostic methods and techniques are continuously being proposed. Condition monitoring techniques seem the most effective tools to minimize operational and maintenance costs and reduce downtimes by early detection of faults.
This paper is aimed at reviewing the state of the art of condition monitoring for horizontal axis wind turbines. After a brief introduction presenting the current trends in the market of wind energy, the paper reviews the most common failure modes of wind turbines and the traditional approach to maintenance. The core of this study details the state of the art in the field of system architectures, sensors and signal processing techniques for the diagnostic of faults in wind turbine components. Finally, some general conclusions are drawn on the overall trends in the field of condition monitoring of wind turbines.