bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Qualitative Numerical Analysis of Rotor-Casing Interactions in Centrifugal Compressors of Helicopter Engines
Authors: Meingast Markus B. , Batailly Alain , Legrand Mathias , Ousty Jean-Philippe 
Published: February 2014

In experimental and numerical investigations of unilateral contact and friction induced rotor-casing interactions, a variety of complex phenomena is expected. Although most of the features of the structural responses can be explained within a simplifying linear framework, the nonlinear nature of contact and friction forces induce complicated responses which require an appropriate methodology to be conveniently analyzed. The presented work focuses on a thorough numerical exploration of such undesired events in an attempt to provide a dedicated systematic method of analysis.
Interaction simulations are carried out on the centrifugal compressor of a modern helicopter engine, for which it is assumed that the casing is rigidly distorted along a mathematical shape exhibiting distinct nodal diameters. The proposed work focuses on linear geometric aspects, such as cyclic symmetry and spatial aliasing of engine orders on nodal diameters as well as nonlinear attributes, such as sub- and super-harmonic participations in the response, in order to properly characterize the dynamics of the interaction.
The results are presented as space and time two-dimensional Fourier transforms of the numerically predicted response. Dominant responses are visible along time harmonics of the forcing frequency imposed by the assumed shape of the casing. It is observed that the participation of some nodal diameters in the response is a consequence of both the aliasing effect and superharmonic forcing terms.
A Power Dense Planetary Drive for Rotorcraft Applications
Authors: Ai Xiaolan , Orkin Curtis , Kruse Randy 
Published: February 2014

Increasing power density is an on-going objective for engineers of fixed wing and rotary wing aircraft. The powertrain system is one of the largest contributors to the total mass of the aircraft and the geartrain is the largest contributor to the mass of the powertrain system. As such, the geartrain becomes the primary focus of many power density studies and is the focus of this paper.
Epicyclic geartrains are known to provide high power density and have become the geartrain of choice for the main power flow in virtually all aircraft designs. This paper presents a unique compound planetary design targeting a helicopter main gearbox transmission application. The design significantly improves power density through its innovative planet gear load-sharing configuration along with the utilization of high-performance materials for gears and bearings. Design studies were conducted comparing the power density of this new design to a baseline gearbox design. The results of these studies demonstrate an estimated 38% power density improvement over the baseline configuration. Of the total improvement, 86% is attributed to the novel load-sharing configuration while 14% is attributed to utilization of advanced materials and processes.
Design Methods for Integrated Design of Blast Resistance Panels and Materials
Authors: Jang Sungwoo , Choi Hae-Jin 
Published: February 2014

Integrated Materials and Products Design (IMPD) differs in the way that materials as well as product layout are designed or optimized in a concurrent manner to meet design requirements. IMPD allows the specific performance required in a product to be achieved by tailoring materials and product, since system performance will not be limited by a pre-chosen material employed in conventional, material-selection-based design. In this study, Blast Resistance Panels (BRPs) with square honeycomb core are designed based on this new design approach to further enhance the performance of BRPs.
We employ multi-level design methods for the integrated design of blast resistance panels and materials. Along with the traditional multi-level optimization of BRP, another design approach, Analytical Target Cascading (ATC) is introduced for a comparative design study in the BRP design. In this article, we compare the design results and design exploration efficiency of the two multi-level design methods in designing the blast resistance panels as well as those materials. We also discuss the advantage and disadvantage of the methods observed in this study.
Tolerance-Maps for Line-Profiles Constructed From Boolean Operations on Primitive T-Map Elements
Authors: He Y. , Davidson J. K. , Shah Jami J. 
Published: February 2014

For purposes of automating the assignment of tolerances during design, a math model, called the Tolerance-Map (T-Map), has been produced for most of the tolerance classes that are used by designers. Each T-Map is a hypothetical point-space that represents the geometric variations of a feature in its tolerance-zone. Of the six tolerance classes defined in the ASME/ANSI/ISO Standards, only one attempt has been made at modeling line-profiles [1], and the method used is an intuitive kinematic description of the allowable displacements of the middle-sized profile within its tolerance-zone. The objective of this paper is to describe an alternative method of construction, one that is much more amenable to computer automation, to obtain the T-Map of any line-profile.
Tolerances on line-profiles are used to control cross-sectional shapes of parts, even mildly twisted ones such as those on turbine or compressor blades. Such tolerances limit geometric manufacturing variations to a specified two-dimensional tolerance-zone, i.e. an area, the boundaries to which are curves parallel to the true profile. The single profile tolerance may be used to control position, orientation, and form of the profile.
The new method requires decomposing a profile into segments, creating a solid-model T-Map primitive for each, and then combining these by the Boolean intersection to generate the T-Map for a complete line profile of any shape. To economize on length, the scope of this paper is limited to line-profiles having any polygonal shape.
Rethinking the Comprehensive Test on Qualitative Reasoning for Designers
Authors: Khorshidi Maryam , Shah Jami J. , Woodward Jay 
Published: February 2014

A battery of tests assessing the cognitive skills needed for the conceptual design is being developed. Tests on Divergent thinking and visual thinking are fully developed and validated. The first version of the qualitative reasoning test has also been developed; this paper focuses on the lessons learned from testing of the first version of the test (alpha version) and the improvements made to it since then.
A number of problems were developed for each indicator of the qualitative reasoning skill (deductive reasoning, inductive reasoning, analogical reasoning, and abductive reasoning). Later, a protocol study was done with the problems to make sure that the problems assess the desired skills. The problems were also given to a randomly chosen population of undergraduate senior-level or graduate-level engineering students. Data was collected from the test results on the possible correlations between the problems (e.g. technical and non-technical problems); feedback on clarity, time allocation, and difficulty for each problem was also collected. Based on all of the observed correlations, the average performance of the test takers, and test parameters such as validity, reliability, etc. the beta version of the test is constructed.
An Approach for Managing Engineering Changes in Product Families
Authors: Raffaeli Roberto , Malatesta Marco , Marilungo Eugenia , Germani Michele 
Published: February 2014

Product development is characterized by continuous updating of existing solutions in order to cope with new market requirements. Families of product variants are used to satisfy the needs of new potential customers and penetrate new market niches.
New requirements impact on the structure of a product to be changed and also on the other instances of the family which share common parts. Several change management approaches have been proposed in the literature but they are limited to analysis of a single product instance.
This paper proposes a dependency-based change propagation approach which is able to cope with engineering changes extended to product families. The proposed tool is based on a multilevel representation of the product structure, where functions, modules and physical parts are defined and interrelated. This system allows evaluating the consequences of engineering changes introduced in the family structure and computing indices of the impact on several design for X contexts.
The tool was tested within the R&D department of a large sized company producing household appliances. Gather data are presented and analyzed to identify potentialities and shortcomings of the approach.
A Library of Feature Fitting Algorithms for GD&T Verification of Planar and Cylindrical Features
Authors: Mohan Prashant , Shah Jami , Davidson Joseph K. 
Published: February 2014

Conformation of a manufactured feature to the applied geometric tolerances is done by analyzing the point cloud that is measured on the feature. To that end, a geometric feature is fitted to the point cloud and the results are assessed to see whether the fitted features lies within the specified tolerance limits or not. Coordinate Measuring Machines (CMMs) use feature fitting algorithms that incorporate least square estimates as a basis for obtaining minimum, maximum, and zone fits. However, a comprehensive set of algorithms addressing the fitting procedure (all datums, targets) for every tolerance class is not available. Therefore, a Library of algorithms is developed to aid the process of feature fitting, and tolerance verification. This paper addresses linear, planar, circular, and cylindrical features only. This set of algorithms described conforms to the international Standards for GD&T.
In order to reduce the number of points to be analyzed, and to identify the possible candidate points for linear, circular and planar features, 2D and 3D convex hulls are used. For minimum, maximum, and Chebyshev cylinders, geometric search algorithms are used. Algorithms are divided into three major categories: least square, unconstrained, and constrained fits. Primary datums require one sided unconstrained fits for their verification. Secondary datums require one sided constrained fits for their verification. For size and other tolerance verifications we require both unconstrained and constrained fits.
Modernization of Main Helicopter Gearbox With Asymmetric Tooth Gears
Authors: Shankin Sergey I. , Stupakov Alexander A. , Glikson Igor L. , Ananiev Viacheslav M. , Kapelevich Alexander L. 
Published: February 2014

This paper describes the research and development of asymmetric tooth spur gears for modernization of the light multipurpose helicopter gearbox amplifying its load capacity to utilize more powerful turboshaft engines.
The paper also presents numerical design data related to development this gearbox.
Kinetostatic Design-Refinement of Articulated Knee Braces
Authors: Jun Seung-kook , Zhou Xiaobo , Ramsey Daniel K. , Krovi Venkat N. 
Published: February 2014

Knee bracing has been used to realize a variety of functional outcomes in both sport and rehabilitation application. Much of the literature focuses on the effect of knee misalignment, force reduction and superiority of custom braces over commercial over-the-counter braces. Efforts on developing exoskeletons to serve as knee augmentation systems emphasize actuation of joints, which then adds to bulkiness of ensuing designs.
In lieu of this, we would like to employ a semi-active augmentation approach (by addition of springs and dampers). Such an approach serves to redirect power (motions and forces) to achieve the desired functional outcomes from the knee braces. However, the suitable selection of geometric dimensions of the brace and spring parameters to achieve desired motion- and force-profiles at the knee remains a challenge. We therefore introduce a two-stage kinetostatic design process to help customize the brace to match a desired kinematic/static performance.
Design Method for Optimizing Contact Ratio of Hypoid Gears
Authors: Miyamura Hiromi , Shibata Yoshikatsu , Inagaki Mizuho , Aoyama Takayuki 
Published: February 2014

Innumerable solutions can be obtained when the pitch surface of a hypoid gear is solved from the requirements of two cones. The pitch angle is determined by the Gleason method based on the idea that the tooth lengthwise curvature corresponds to the cutter radius. This study proposes a new design method that can optimize the contact ratio using the pitch angle, using the new tooth geometry advocated by Honda. The balance of the contact ratios of the convex and concave sides of a gear can be optimized by designing the pitch angle. By optimizing the contact ratio, noise and vibration performance can be improved. In addition, highly efficient gear design can be achieved by decreasing the spiral angle.
The effectiveness of this optimized design method is confirmed by measuring transmission errors under load. Design examples of a highly efficient gear by reducing the spiral angle and a gear which ensures high noise and vibration performance are shown. Using this proposed method expands the design freedom of hypoid gears.
Business Domain Decision Method for Manufacturing and Service
Authors: Onda Hiroomi , Miwa Toshiharu , Jackson Vincent R. , Park Dahwe , Reynolds Kevin W. , Beiter Kurt A. 
Published: February 2014

This paper deals with a study on a method to support the decision on entering business areas in a business model consisting of manufacturing and service. This method divides the business model into business areas by the functions that support a company to decide whether it should enter business areas.
This method prioritizes the areas from the aspects of profit opportunities, barriers to entry, and interactions between the areas. This method reduces the time to decide which business area to enter and reduces the number of examination objects to the number of business areas (n) or fewer from the total number of possible combinations (2 to the 2nd power n).
To confirm the efficiency of this method, we demonstrated two case studies in the IT services industry. In the first case study, from the perspective of a UPS battery supplier, the number of examination objects is 3 when the number of business areas is 11. And the first case study indicates that a suitable strategy for a battery supplier is to concentrate on the strategy of supplying batteries. In the second case study, from the perspective of an IT service provider, the number of examination objects is 10 when the number of business areas is 11. The second case study indicates that a suitable strategy for an IT service provider is vertical integration from software development to data center operation and hardware manufacturing.
Variation Simulation of Stresses Using the Method of Influence Coefficients
Authors: Lorin Samuel , Lindkvist Lars , Söderberg Rikard 
Published: February 2014

In every manufacturing situation there are geometric deviations leading to variation in properties of the manufactured products. Variation affects the manufacturability, functions and aesthetics of the products. Therefore, a number of methods and tools have been developed during the last 20 years in order to assure the geometric quality and to minimize the effect of variability. These methods and tools have mainly been developed for rigid bodies or sheet metal components.
Plastics or composites have been an increasingly popular material due to their flexible mechanical properties and their relative ease in manufacturing. However, their mechanical properties are introducing challenges that have not often been addressed in the process of geometry assurance. One challenge is to assure that the stresses introduced, as a consequence of non-nominal assembly in the positioning system, are kept well below critical limits during the conditions of use.
In this paper, we are proposing the use of the method of influencing coefficients (MIC) to simulate the distribution of von Mises stresses in assembled components. This method will be compared to the more flexible but computationally much heavier Direct Monte Carlo (DMC) method, which is not suitable for variation simulation due to the large number of runs required for statistical inference.
Two industrial case studies are presented to elicit the need of the proposed method.
Deflection of an Eccentric Tooth of a Comb Drive in an Electrostatic Field
Authors: Meijaard J. P. , Krijnen B. , Brouwer D. M. 
Published: February 2014

The elastic deflection of a comb drive tooth in an electrostatic field is considered. The tooth can be symmetrically located between two rigid teeth of the matching comb, in which case the problem reduces to a pure bifurcation problem for which the critical voltage can be determined. Alternatively, due to an approximate straight-line mechanism, the tooth can have a uniform initial lateral displacement and a smooth curve of equilibria is found which has a limit point, after which pull-in occurs.
An assumed deflection shape and a series expansion of the electrostatic capacity yield the deflection curves for the case with a uniform initial lateral displacement. This shows that pull-in occurs at a voltage that is reduced by a factor that is about proportional to the two-third power of the relative lateral initial displacement.
The theoretical results have been experimentally tested. The results show a qualitative agreement, but the experimental deflections are larger and the pull-in voltages are lower. These differences can be explained from neglected fringe fields and deviations from the nominal shape.
A Concept of Camera Test-Bench for Testing Camera Based Advanced Driver Assistance Systems
Authors: Tan Yin , Hassan Bassem 
Published: February 2014

About 1.5 million traffic accidents occur every year in European traffic; most of them are results of careless driving behavior, for example unintentional lane departure. Studies show that these accidents could often be avoided, if the driver would react only half a second earlier. Therefore, advanced driver assistance systems (ADAS) and especially the camera based ADAS increasingly gain importance in the automobile industry because of their diverse functions, for example the lane keeping assistance. Their development must contain an excessive and accurate testing process, in order to contribute to a reliable result in the common use. The importance of the testing methods and environments is growing due to several reasons, for example the need for more flexibility during testing and cost-reduction at the same time. Those requirements can be fully fulfilled by the use of virtual environments. To simplify the testing process, the virtual environment does not need to be as realistic as possible. It only has to provide necessary features for the camera system. Due to different detection algorithms for diverse assistance functions, the virtual environment needs determined characteristics, which are crucial for further precise analyses.
This paper presents a concept to create a camera test-bench for testing of camera based ADAS, by adapting an existing virtual environment for the camera system, identifying and enhancing the important features for the testing detection function while enable a flexible and low-cost testing environment. The testing ADAS shall record the virtual driving scenes and deliver the same results as in real environments.
First, possible existing approaches of testing processes shall be presented. In this paper, the concept is to shown by the example of road detection. The focus lies on the lane markings and the ground. While the separation lines between diverse objects are clearly visible in the virtual environment, the real ones often differ due to road condition or lighting intensity. The differences must be considered and corrected by creating a shader which adjusts the scenes, before the virtual representations can be applied for testing camera based ADAS. Furthermore, for testing other functions, the shader shall be expanded and contain more relevant feature parameters for different test functions. All in all, as much as possible camera based ADAS shall be tested with a virtual environment and the tests shall help accelerating the development time and improving the quality of camera based ADAS.
Optimal Design of the IRSBot-2 Based on an Optimized Test Trajectory
Authors: Germain Coralie , Caro Stéphane , Briot Sébastien , Wenger Philippe 
Published: February 2014

This paper deals with the design optimization of the IRSBot-2 based on an optimized test trajectory for fast pick and place operations. The IRSBot-2 is a two degree-of-freedom translational parallel manipulator dedicated to fast and accurate pick-and-place operations.
First, an optimization problem is formulated to determine the optimal test trajectory. This problem aims at finding the path defined with s-curves and the time trajectory that minimize the cycle time while the maximum acceleration of the moving platform remains lower than 20 G and the time trajectory functions are C2 continuous.
Then, two design optimization problems are formulated to find the optimal design parameters of the IRSBot-2 based on the previous optimal test trajectory. These two problems are formulated so that they can be solved in cascade. The first problem aims to define the design parameters that affect the geometric and kinematic performances of the manipulator. The second problem is about the determination of the remaining parameters by considering elastostatic and dynamic performances.
Finally, the optimal design parameters are given and will be used for the realization of an industrial prototype of the IRSBot-2.
The Calculation of the Degree of Parallelization of Documents and Risk Estimation in Product Development Processes
Authors: Schabacker Michael , Szélig Nikoletta , Vajna Sándor 
Published: February 2014

In [1] different process modeling methods were evaluated and a tri-process modeling tool [2] was developed. After that it is often the case that the recorded product development processes have to be optimized in this tool. Previous studies of the authors have described the stages of process optimization in detail [3]. One of these stages was realized in [4] with the BAPM method. It has shown that there is no suitable method for the realization of the stage of process optimization called Simultaneous Engineering in the research literature.
The aim of this paper is to show one approach to realize Simultaneous Engineering by quantifying the degree of parallelization of documents. With the improved triangle it is possible to represent the relation between parallelization, resources and risk. This paper allows a quantified estimation of the change in the risk to be provided during the parallelization of the elements of a process.
Companies applying the optimization approaches discussed above will be able to perform more efficiently and create more efficient product development projects.