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.

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.

Identification of Nonlinear Systems by Haar Wavelet

This study addresses the identification of autonomous nonlinear systems. It is assumed that the function form in the nonlinear system is known, leaving some unknown parameters to be estimated. It is also assumed that the free responses of the system can be measured. Since Haar wavelets can form a complete orthogonal basis for the appropriate function space, they are used to expand all signals. In doing so, the state equation can be transformed into a set of algebraic equations in unknown parameters. The technique of Kronecker product is utilized to simplify the expressions of the associated algebraic equations. Together with the least square method, the unknown system parameters are estimated. Several simulation examples verify the analysis.

Identification of Structural Systems With Limited Number of Sensors and Actuators

The common assumption in the so-called linear inverse vibration problem, which provides the mass/stiffness/damping matrices of second order dynamic models, is the availability of a full set of sensors and actuators. In “reduced-order” problems (with limited number of instrumentation), only the components of the eigenvector matrix regarding the measured degrees of freedom can be successfully identified while nothing can be said about the components connected to the unmeasured degrees of freedom. This paper presents a recently developed “reduced-order” model and expands such a model to a “full-order” one that is quite useful in damage detection. The five representative categories of “reduced-order” problems, defined by considering different types of geometrical conditions, are analyzed and a discussion on their solution space has been performed. The effectiveness and robustness of this approach is shown by means of a numerical example.

Stress and Strength of Butt Circular Shaft With Metal Columns Subjected to Torques

Stress analysis of the butt circular shaft with three uniformly distributed metal columns subjected to external torques are carried out by using three-dimensional finite element method. The loading capability of the butt circular shaft is measured. It was found that torque acting on the cross-section of adhesive layer is simultaneously withstood by the adhesive layer and the metal columns; The ratio of the torque withstood by metal columns to that withstood by adhesive layer increases with increase of the ratio of Young’s modulus of metal columns to that of the circular shaft; The metal columns enhance and improve the reliability of the joints; The strength of the butt adhesive circular shafts increases with increase of the ratio of the yield stress of the metal columns to that of circular shafts.