The Effects of Soil Gradation on System Level Dynamic Response

A finite element formulation for the dynamic response of gear pairs is proposed. Following an established approach in lumped parameter gear dynamic models, the static solution is used as the excitation in a frequency domain solution of the finite element vibration model. The nonlinear finite element/contact mechanics formulation provides an accurate calculation of the static solution and average mesh stiffness that are used in the dynamic simulation. The frequency domain finite element calculation of dynamic response compares well with numerically integrated (time domain) finite element dynamic results and previously published experimental results. Simulation time with the proposed formulation is two orders of magnitude lower than numerically integrated dynamic results. This formulation admits system level dynamic gearbox response, which may include multiple gear meshes, flexible shafts, rolling element bearings, housing structures, and other deformable components.

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Analysis on the Effect of Input Impact Profiles in Drop Test

Volume 5: Electronics and Photonics ◽

10.1115/imece2007-41138 ◽

2007 ◽

Cited By ~ 2

Author(s):

Jiang Zhou ◽

Ratna P. Niraula ◽

Kendrick Aung

Keyword(s):

Dynamic Response ◽

Impact Load ◽

Block Diagram ◽

Input Pulse ◽

Drop Test ◽

System Level ◽

System Response ◽

Time Duration ◽

Board Level ◽

The Impact

The objective of this paper is to develop an analytical or mathematical predicative model for the evaluation of dynamic response of a structural element in a microelectronic or an optoelectronic product to an impact load occurring as a result of drop or shock test. Closed-form theoretical solution was obtained to simulate the board level drop test. The block diagram based SIMULINK analysis was introduced to determine the response with various impact configurations for the system level drop test as well. This study will help reliability engineers to design the impact input profiles and obtain the desired responses, and to calibrate and validate finite element analysis results quickly for both board level and system level drop test. It was found that time durations of the input profiles play an important role in the dynamic response. The system response can be designed by carefully choosing the impact time duration. Certain input pulse time results in the response with very low ringing after first or second peaks.

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Shock and Dynamic Loading in Portable Electronic Assemblies: Experimental Results

Journal of Electronic Packaging ◽

10.1115/1.4005090 ◽

2011 ◽

Vol 133 (4) ◽

Author(s):

A. F. Askari Farahani ◽

M. Al-Bassyiouni ◽

A. Dasgupta

Keyword(s):

Dynamic Response ◽

Dynamic Loading ◽

Transient Response ◽

Failure Modes ◽

Dynamic Contact ◽

System Level ◽

Printed Wiring Board ◽

Electronic Product ◽

Electronic Assemblies ◽

Plastic Housing

The development of portable electronics poses design challenges when evolving new designs for high strain-rate life cycle loading, such as in drop events, blast events, vibration, ultrasonic process steps, etc. This paper discusses an experimental investigation of the transient response of a portable electronic product and its subassemblies to dynamic mechanical loading encountered in drop and shock conditions. The portable electronic product tested in this study consists of a circuit card assembly and a battery pack supported in a two-piece plastic housing with a separate battery compartment. Dynamic loading, consisting of various shock profiles, is applied using an electrodynamic shaker. A number of drop tests are also conducted on a drop tower. Fourier transform technique (FFT) is utilized to analyze the dynamic response of the printed wiring board and the plastic housing in the frequency domain. Tests at the subassembly level are used to study the dynamic response of the individual constituents. The nonlinear interactions due to dynamic contact between these subassemblies are then investigated through shock and drop testing at the system level. These results will be used in a subsequent study to investigate the ability of finite element models to accurately capture this transient response of complex portable electronic assemblies under shock and drop loading. The long-term goal of this combined study is to demonstrate a systematic modeling methodology to predict the drop response of future portable electronic products, so that relevant failure modes can be eliminated by design iterations early in the design cycle.

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A Frequency Domain Finite Element Approach for Three-Dimensional Gear Dynamics

Volume 6: ASME Power Transmission and Gearing Conference; 3rd International Conference on Micro- and Nanosystems; 11th International Conference on Advanced Vehicle and Tire Technologies ◽

10.1115/detc2009-87525 ◽

2009 ◽

Cited By ~ 1

Author(s):

Christopher G. Cooley ◽

Robert G. Parker ◽

Sandeep M. Vijayakar

Keyword(s):

Finite Element ◽

Dynamic Response ◽

Frequency Domain ◽

Dynamic Models ◽

Three Dimensional ◽

Transmission Error ◽

System Level ◽

Element Formulation ◽

Lumped Parameter ◽

Static Transmission Error

A finite element formulation for the dynamic response of gear pairs is proposed. Following an established approach in lumped parameter gear dynamic models, the static transmission error is used as the excitation in a frequency domain solution of the finite element vibration model. The nonlinear finite element/contact mechanics formulation provides superior calculation of static transmission error and average mesh stiffness that is used in the dynamic simulation. The frequency domain finite element calculation of dynamic response correlates to numerically integrated (time domain) finite element dynamic results and previously published experimental results. Simulation time with the proposed formulation is two orders of magnitude lower than numerically integrated dynamic results. This formulation admits system level dynamic gearbox response, which may include multiple gear meshes, flexible shafts, rolling element bearings, and housing structures.

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Design of Proof Mass and System-Level Simulation of a Micromachined Electrostatically Suspended Accelerometer

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.317-319.1631 ◽

2011 ◽

Vol 317-319 ◽

pp. 1631-1634

Author(s):

Zhen Wan ◽

Feng Cui ◽

Yun Kui Zhang ◽

Wu Liu ◽

Wen Yuan Chen ◽

...

Keyword(s):

Dynamic Response ◽

Proof Mass ◽

Sacrificial Layer ◽

Perforated Plate ◽

Element Model ◽

System Level ◽

Squeeze Film ◽

System Level Simulation ◽

Squeeze Film Damping ◽

Level Model

A six-axis Micromachined Electrostatically Suspended Accelerometer (MESA) which is based on LIGA-type microfabrication was designed. MESA employs a levitated perforated plate as its proof mass. Three main purposes are considered for the design of the perforated proof mass: (1) reducing squeeze-film effect; (2) improving the dynamic response of MESA; (3) facilitating the etching of sacrificial layer under the plate. This paper utilized a finite element model for evaluating air squeeze film damping effect of perforated proof mass. Among several designs of perforated proof mass, the best choice was found. Besides, a system-level model created in CoventorWare is used to evaluate the effect of squeeze film damping and the dynamic response of the MESA.

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Microfabrication Process-Driven Design, FEM Analysis and System Modeling of 3-DoF Drive Mode and 2-DoF Sense Mode Thermally Stable Non-Resonant MEMS Gyroscope

Micromachines ◽

10.3390/mi11090862 ◽

2020 ◽

Vol 11 (9) ◽

pp. 862 ◽

Cited By ~ 1

Author(s):

Syed Ali Raza Bukhari ◽

Muhammad Mubasher Saleem ◽

Umar Shahbaz Khan ◽

Amir Hamza ◽

Javaid Iqbal ◽

...

Keyword(s):

Dynamic Response ◽

Microelectromechanical Systems ◽

System Modeling ◽

Silicon On Insulator ◽

System Level ◽

Voltage Sensitivity ◽

Thermally Stable ◽

Sense Mode ◽

Drive Mode ◽

Mems Gyroscope

This paper presents microfabrication process-driven design of a multi-degree of freedom (multi-DoF) non-resonant electrostatic microelectromechanical systems (MEMS) gyroscope by considering the design constraints of commercially available low-cost and widely-used silicon-on-insulator multi-user MEMS processes (SOIMUMPs), with silicon as a structural material. The proposed design consists of a 3-DoF drive mode oscillator with the concept of addition of a collider mass which transmits energy from the drive mass to the passive sense mass. In the sense direction, 2-DoF sense mode oscillator is used to achieve dynamically-amplified displacement in the sense mass. A detailed analytical model for the dynamic response of MEMS gyroscope is presented and performance characteristics are validated through finite element method (FEM)-based simulations. The effect of operating air pressure and temperature variations on the air damping and resulting dynamic response is analyzed. The thermal stability of the design and corresponding effect on the mechanical and capacitive sensitivity, for an operating temperature range of −40 °C to 100 °C, is presented. The results showed that the proposed design is thermally stable, robust to environmental variations, and process tolerances with a wide operational bandwidth and high sensitivity. Moreover, a system-level model of the proposed gyroscope and its integration with the sensor electronics is presented to estimate the voltage sensitivity under the constraints of the readout electronic circuit.

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