Product Platform Design and the Gate Model: Lessons From Industry Case Studies

Organizations that seek long-term success no longer depend on just one product but rather a platform of products that target key markets. Time-to-market pressures and globally distributed engineering design environments demand support through life-cycle models, particularly in the early stages of product development, for an effective product platform. Product definition and structured processes such as gate models are necessary in platform design for organizations to focus their effort on developing families of products that share common components and technology. This paper discusses conventions and research directions in different industries, describes methods in use, and explains a roadmap for product platform development. Case studies of laser printer, industrial robot, and AC motor drive controller platform development further explore challenges in platform design and the role of gate models. The paper concludes with gate model lessons and proposed work to further this research including decision analytic and system approaches.

Treating Uncertainties in Multibody Dynamic Systems Using a Polynomial Chaos Spectral Decomposition

This study addresses the critical need for computational tools to model complex nonlinear multibody dynamic systems in the presence of parametric and external uncertainty. Polynomial chaos has been used extensively to model uncertainties in structural mechanics and in fluids, but to our knowledge they have yet to be applied to multibody dynamic simulations. We show that the method can be applied to quantify uncertainties in time domain and frequency domain.

Applying Functional Modeling as a Unifying Basis for Design for Six Sigma Execution

This paper explores the applicability of the most recently developed methods in functional modeling to Design for Six Sigma transfer function development and requirements flowdown. An example created during a collaborative research project between the General Motors R&D Center and the University of Missouri – Rolla is used to demonstrate the benefits of using standardized functional modeling during conceptual design. The proposed standard for creating the functional models is the Functional Basis. The Functional Basis is a list of function and flow terms that can be used to describe electro-mechanical systems. The example presented in this paper is based on the parking brake system of a passenger car. Module heuristics, function-based rules for partitioning systems, were used to define the sub-systems during the requirements flowdown example. The functional modeling techniques used in this example provide a standard method of capturing current engineering design knowledge while allowing additional knowledge to be discovered.

Optimum Design of Inductors Used for Wireless Power Transmission Micro-Module

The micro-inductor is a key component in wireless power transmission micro modules. In this paper, an optimum design for the micro-inductor was studied and related MEMS fabrication techniques were also developed. Commercial electromagnetic property analysis software, ANSOFT, was used to screen the main design factors of the micro-inductor. It was found that the high inductance and high quality factors of the micro-inductor implied high power transmission efficiency for the micro-module’s wireless power transmission. The electrical performance of the micro-inductor was affected by the thermal stress and thermal strain induced in the operational environment of the wireless power transmission micro-module. In order to investigate the reliability of the micro-inductor, commercial stress analysis software, ANSYS, was used to calculate thermal stress and thermal strain. The deformed model of the micro-inductor was then imported into ANSOFT in order to calculate its electrical properties. Glass substrate Pyrex 7740 was used to reduce the substrate loss of the magnetic flux of the micro-inductor. The surface micromachining technique, a kind of MEMS processing, was chosen to fabricate the micro-inductor; the coil of the micro-inductor was electroplated with copper to reduce the series resistance. The minimum line width and line space of the coil were 20 μm and 20 μm respectively. Polyimide (PI) was used for supporting the structure of micro-inductors. The maximum shear stress was 74.09MPa and the maximum warpage was 2.197 μm at a thermal loading of 125°C. For the simulated data, the most suitable areas for 31-turn and 48-turn coils were at an area ratio of 1.27 and 2, respectively. The electrical properties of the inductors changed slightly under thermal loading.

Synchronization in Dual Delay Line SAW Sensors

Surface acoustic wave (SAW) sensors are self-excited oscillators. Self-excitation is a consequence of the finite amount of delay in the circuit. The oscillation frequency is affected by the wave propagation speed which further depends on surface adsorption. Therefore, measurement on the surface adsorption is done by measuring the frequency change of the self-excited oscillation. In dual delay line oscillators the difference between the surface physical conditions is reflected through the difference in oscillation frequencies. Delay differential equations are used to model the sensor. Bifurcation analysis of the averaged equations indicates the presence of synchronization. The occurrence of synchronization is further demonstrated through numerical simulations. Synchronization makes the frequency measurement irrelevant. We propose phase measurement as an alternative in the presence of strong coupling between the two oscillators.

Nonlinear Isolator Optimization Using RMS Cost Function

In this paper using a modified averaging method the frequency response of a general nonlinear isolator is obtained. Stiffness and damping characteristics are considered cubic functions of displacement and velocity through the isolator. Analytical results are compared with those obtained by numerical integration in order to validate the closed form solution for strongly nonlinear isolator. While increasing the nonlinearity in the system improves the response of the isolator, stability and jump avoidance conditions set boundary limits for the parameters. The effects of nonlinear parameters to avoid jump phenomenon are discussed in detail. The set of parameters where the system behaves regularly are found and the nonlinear isolator is optimized based on RMS optimization method. Using this method the RMS function of absolute acceleration of the sprung mass is minimized versus the RMS function of relative displacement.

Fluid-Coupled Vibrations of Immersed Spent Nuclear Racks: A Nonlinear Model Accounting for Squeeze-Film and Dissipative Phenomena

Fluid-coupling effects lead to a complex dynamical behavior of immersed spent fuel assembly storage racks. Predicting their responses under strong earthquakes is of prime importance for the safety of nuclear plant facilities. In the near-past we introduced a simplified linearized model for the vibrations of such systems, in which gap-averaged velocity and pressure fields were described analytically in terms of a single space-coordinate for each fluid inter-rack channel. Using such approach it was possible to generate and assemble a complete set of differential-algebraic equations describing the multi-rack fluid coupled system dynamics. Because of the linearization assumptions, we achieved computation of the flow-structure coupled modes, but also time-domain simulations of the system responses. However, nonlinear squeeze-film and dissipative flow effects, connected with very large amplitude responses and/or relatively small water gaps, cannot be properly accounted unless the linearization assumption is relaxed. Such is the aim of the present paper. Here, using a similar approach, we generalize our theoretical model to deal with nonlinear flow effects. Besides that the proposed methodology can be automatically implemented in a symbolic computational environment, it is much less computer-intensive than finite element formulations. Using the proposed technique, computations of basic flow-coupled rack configurations subjected to impulse excitations are presented, in order to highlight the essential features of such systems as well as the relevance of squeeze-film and dissipative effects. Finally, more realistic simulations of complex system responses to strong seismic excitations are presented and discussed.

Routes to Chaos in Squeeze-Film Dampers

This work reports on a numerical study undertaken to investigate the imbalance response of a rigid rotor supported by squeeze-film dampers. Two types of damper configurations were considered, namely, dampers without centering springs, and eccentrically operated dampers with centering springs. For a rotor fitted with squeeze-film dampers without centering springs, the study revealed the existence of three regimes of chaotic motion. The route to chaos in the first regime was attributed to a sequence of period-doubling bifurcations of the period-1 (synchronous) rotor response. A period-3 (one-third subharmonic) rotor whirl orbit, which was born from a saddle-node bifurcation, was found to co-exist with the chaotic attractor. The period-3 orbit was also observed to undergo a sequence of period-doubling bifurcations resulting in chaotic vibrations of the rotor. The route to chaos in the third regime of chaotic rotor response, which occurred immediately after the disappearance of the period-3 orbit due to a saddle-node bifurcation, was attributed to a possible boundary crisis. The transitions to chaotic vibrations in the rotor supported by eccentric squeeze-film dampers with centering springs were via the period-doubling cascade and type 3 intermittency routes. The type 3 intermittency transition to chaos was due to an inverse period-doubling bifurcation of the period-2 (one-half subharmonic) rotor response. The unbalance response of the squeeze-film-damper supported rotor presented in this work leads to unique non-synchronous and chaotic vibration signatures. The latter provide some useful insights into the design and development of fault diagnostic tools for rotating machinery that operate in highly nonlinear regimes.

Virtual Automated Transit System (VATS) and Intelligent Transportation Systems (ITS) Application to Intermodal Freight Movements in Northeastern Illinois

This paper addresses the issues faced by local and state governments concerning increasing traffic congestions, inadequate roadway design and traffic safety problems caused by the freight truck traffic; on the other hand, the freight industry is seeking to improve productivity by having easy access and direct routes between the intermodal facilities and the interstate highway system.

Contact Modelling in Method of Influence Coefficient for Variation Simulation of Sheet Metal Assemblies

Sheet metal assembly is a common manufacturing process for several products such as automobiles and airplanes. Since all manufacturing processes are affected by variation and products need to have a high geometric quality, geometry related production problems must be analyzed during early design phases. Often, the analysis is done by using FEA (Finite Element Analysis) to include the compliant behavior of the parts. There are many variables that affect the geometric quality and to include many of them in a FEA simulation is often very time-consuming. One way of performing the simulations relatively fast is to establish linear relationships between part deviation and assembly spring-back deviation by using Method of Influence Coefficient (MIC). However, one limitation with the method is that the method does not consider contact between the parts. This means that the parts are allowed to penetrate each other. In some cases when contact occurs, this method will not simulate the real behavior of the assembly. This paper presents a contact modeling technique that can be implemented in the MIC. The contact modeling procedure consists of a contact detection algorithm and a solution algorithm for finding the position of equilibrium. When implemented, the MIC still only requires two FEA calculations. This paper describes the steps in the contact algorithm and how it can be used in MIC, finally a case study is analyzed.