Lou Wenzhong

Failure of a MEMS switch after environmental test

A MEMS switch based on electro-thermal and electro-explosion has been packaged before its humidity test, temperature shock test and ballistic shock test are taken. Some devices failed after the tests. The analysis of such a device is given in this paper.

High impact-induced failure of a novel solid MEMS switch

Due to the rapidly growing MEMS initiator market and the needs for smaller, safer and higher integration, more advanced switches are in demand. The novel solid MEMS switch can improve the security and reliability of MEMS initiator, while the leads of its package are weak under high impact. This paper mainly studied the leads reliability of the novel solid MEMS switch under high impact by FEM simulation analysis. Through simulation analysis, the mainly weakness and the potential failure modes of the leads under high impact can be obtained, which can provide theory reference for the design and application of the novel solid MEMS switch.

Visualization of real-time logistics monitoring microsystem based on MEMS sensors

Visualization of real-time logistics monitoring microsystem is designed based on MEMS sensors, which are high ability, low power consumption and low cost. The MEMS acceleration sensor BMA280, the MEMS pressure sensor BMP085, the display module, the memory module and the radio frequency (RF) module are integrated in the intelligent microsystem. Intelligent microsystem block diagram is shown in Fig.1 and the software flowchart is shown in Fig.2.

The effect of micro-spring stiffness changes on the typical MEMS S&A device

The purpose of this paper is to study the remove insurance time with different stiffness of typical MEMS S&A (Safety and Arming)device, which are composed of the micro spring, slider, zigzag slot and card lock. According to higher dynamics theory, the zigzag slot collision energy loss, card lock closure features such as abstract the slider in the theoretical model of motion process, we used MATLAB to work out the displacement-time relationship of slider, and get the theoretical remove insurance time; Then we used ANSYS LS/DYNA finite element analysis of the structure, obtained the simulation process of slider displacement-time relationship, and got the numerical remove insurance time. By comparing theoretical analysis and simulation analysis, we can get the MEMS S&A devices remove insurance time variation with spring stiffness, and verify the correctness of the simulation analysis, which provide a theoretical basis for the design of the type MEMS S&A device.

Ultrasonic attenuation based high concentration micron particle measurement

Measuring micron particle density becomes challenged in a high concentration level. To address this issue, we proposed ultrasonic attenuation to measure high concentration micron particles of cement powder in gas-solid two phase flow. An ultrasonic inspection system and a particulate matter concentrations simulation chamber were built respectively to demonstrate relationship between signal attenuation and particle concentration. The results show that ultrasonic attenuation method is quite effective to measure the concentration of micron particles in gas-solid two phase flow.

The MEMS experiment and numerical simulations based on the explosion protection of micro-scale vehicles model

Landmine and improvised explosive (IED) are the major threat to the occupants inside armored vehicles. IED-detonation introduced Global effects of severe acceleration can greatly hurt vehicle occupants. To investigate the responses of armored vehicle and its occupants subjected to landmine explosion, an low-cost equivalent miniature model of the vehicle replacing real-scale one was built. With a full scale finite element models using HyperMesh software, the miniatures shows similar results as its actual model. The fluid and structure coupled algorithm successfully simulated the phenomena of armored vehicle subjected to landmine. Finally, a MEMS sensor-based experimental setup was employed to monitor vehicle occupant during IED explosion, and its experimental result was in accordance with simulation.

The calculation method of reliability based on MEMS Safety and Arming device

In this paper, aiming at the failure mode with MEMS spring fracture of MEMS S&A (Safety and Arming) device, the dynamic simulation and response surface method are combined to use to establish the relationship between the structure response and the structure random variables. The stress values are fitted by the least square method, and the binary quadratic equation, whose variables are the MEMS springs elastic modulus, the MEMS springs breaking strength and thickness and the output is the value of determination function, is obtained. Finally, using Monte Carlo method for a large number of random state numerical value, obtained the MEMS spring fracture of MEMS S&A device reliability is 0.9999996.

The parametric analysis of the centrifugal insurance mechanism in MEMS safety and arming device

In this paper, a MEMS S&A device has been proposed. The size of the device is φ 12×0.3mm. The role of the centrifugal insurance mechanism is to ensure the safety in handling transportation and storage, and reliable firing with the launch overload. Through establishing the three-dimensional model of the centrifugal insurance mechanism, establishing the force and the parameters of the centrifugal insurance mechanism, deriving the mathematical model according to the rigid dynamic mechanics theory and establishing the finite element model by using ANSYS/LS-DYNA, appropriate centrifugal insurance mechanism is designed to meet two items, one item is deformation of elastic beam can reliably release slider when the speed is more than 30000r/min and the centrifugal insurance mechanism can restrict the slider again when the speed is reduced; the other item is the centrifugal insurance mechanism can effectively restrict the slider to ensure the safety of the device when primary insurance accident arming in handling transportation.

Design of train intelligent fire warning system based on C-MBUS

This paper provides a novel solution to available train network by analyzing and comparing the present development and application situation about kinds of technologies of train network. C-MBUS is proposed for train network and fire warning system. This paper designs a system frame of train intelligent fire warning terminal based on C-MBUS. In the design, using C-MBUS for this project to connect train intelligent fire warning terminal and the smoke fire detector on the train helps users control them easily, security and remotely. What is more, C-MBUS is low voltage and the data transfer rate is high for meaningful data communication.

Algorithm analysis of PHM for sensitive cargo transportation

Several Prognostics and Health Management (PHM) algorithms are to be analyzed in this paper, and the purpose is set to master the know-how of the optimization of the prognostic algorithms. To implement the PHM for sensitive cargo transportation, based on the original data collected during the dedicated tests, applying the microsystem hardware designed and assembled by the research team, as well as the embedded software. At the end, the framework of the system platform in the future is layouted.