Mechanical Reliability of Silicon Microstructures

Author(s):  
Toshiyuki Tsuchiya

Abstract In this article, an overview of the mechanical reliability of silicon microstructures for micro-electro-mechanical systems (MEMS) is given to clarify what we now know and what we still have to know about silicon as a high-performance mechanical material on the microscale. Focusing on the strength and fatigue properties of silicon, attempts to understand the reliability of silicon and to predict the device reliability of silicon-based microstructures are introduced. The effective parameters on the strength and the mechanism of fatigue failure are discussed with examples of measurement data to show the design guidelines for highly reliable silicon microstructures and devices.

PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.


Alloy Digest ◽  
1998 ◽  
Vol 47 (2) ◽  

Abstract Incoloy Alloy 864 is a high performance alloy developed specifically for automotive exhaust system flexible couplings and other exhaust applications. The alloy has a good combination of oxidation and corrosion resistance, with good mechanical strength, stability, and fatigue properties. This datasheet provides information on composition, physical properties, and elasticity. It also includes information on high temperature performance and corrosion resistance as well as joining. Filing Code: SS-708. Producer or source: Inco Alloys International Inc.


1991 ◽  
Vol 22 (5) ◽  
pp. 327-340 ◽  
Author(s):  
K. Høgh Jensen ◽  
J. C. Refsgaard

A numerical analysis of solute transport in two spatially heterogeneous fields is carried out assuming that the fields are composed of ensembles of one-dimensional non-interacting soil columns, each column representing a possible soil profile in statistical terms. The basis for the analysis is the flow simulation described in Part II (Jensen and Refsgaard, this issue), which serves as input to a transport model based on the convection-dispersion equation. The simulations of the average and variation in solute concentration in planes perpendicular to the flow direction are compared to measurements obtained from tracer experiments carried out at the two fields. Due to the limited amount of measurement data, it is difficult to draw conclusive evidence of the simulations, but reliable simulations are obtained of the mean behaviour within the two fields. The concept of equivalent soil properties is also tested for the transport problem in heterogeneous soils. Based on effective parameters for the retention and hydraulic conductivity functions it is possible to predict the mean transport in the two experimental fields.


Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Yuhang Yang ◽  
Zhiqiao Dong ◽  
Yuquan Meng ◽  
Chenhui Shao

High-fidelity characterization and effective monitoring of spatial and spatiotemporal processes are crucial for high-performance quality control of many manufacturing processes and systems in the era of smart manufacturing. Although the recent development in measurement technologies has made it possible to acquire high-resolution three-dimensional (3D) surface measurement data, it is generally expensive and time-consuming to use such technologies in real-world production settings. Data-driven approaches that stem from statistics and machine learning can potentially enable intelligent, cost-effective surface measurement and thus allow manufacturers to use high-resolution surface data for better decision-making without introducing substantial production cost induced by data acquisition. Among these methods, spatial and spatiotemporal interpolation techniques can draw inferences about unmeasured locations on a surface using the measurement of other locations, thus decreasing the measurement cost and time. However, interpolation methods are very sensitive to the availability of measurement data, and their performances largely depend on the measurement scheme or the sampling design, i.e., how to allocate measurement efforts. As such, sampling design is considered to be another important field that enables intelligent surface measurement. This paper reviews and summarizes the state-of-the-art research in interpolation and sampling design for surface measurement in varied manufacturing applications. Research gaps and future research directions are also identified and can serve as a fundamental guideline to industrial practitioners and researchers for future studies in these areas.


Author(s):  
Venkatesh Piradi ◽  
Feng Yan ◽  
Xunjin Zhu ◽  
Wai-Yeung Raymond Wong

Organic solar cells (OSCs) have been considered as a promising cost-effective alternative to silicon-based solar cell counterparts due to their lightweight, mechanical flexibility, and easy fabrication features. Over the past...


2010 ◽  
Vol 4 (2) ◽  
pp. 110-116 ◽  
Author(s):  
Kiwamu Ashida ◽  
◽  
Shizuka Nakano ◽  
Jaehyuk Park ◽  
Jun Akedo

Many micro-scale devices have been developed by applying micro-electro-mechanical systems (MEMS) technology, but MEMS production facilities are large and costly, making it difficult to develop small numbers of trial devices. The novel on-demand MEMS device production system we developed applies two major concepts – that of the microfactory and the introduction of non-MEMS processes in microfabrication. These two concepts have made manufacturing more ecological, economical, agile, and flexible through downsizing, forming an automated production line by connecting standardized unit-processing cells, each of which has a desktop process, a part transfer robot, and a standardized connection interface. These enable any process cell to be connected in any sequence that the target product requires. Four unit-process cells were developed – the micropress cell for fabricating microstructures from thin sheet metal and the miniature aerosol deposition (AD) process cell for fabricating high-performance piezoelectric (PZT) ceramics actuators. The feasibility of the on-demand MEMS production system was demonstrated by the fabrication of a MEMS-like micromirror scanner, proving the potential of on-demand MEMS production in diversified small-lot production.


2016 ◽  
Vol 4 (24) ◽  
pp. 9477-9485 ◽  
Author(s):  
Dinsefa M. Andoshe ◽  
Seokhoon Choi ◽  
Young-Seok Shim ◽  
Seung Hee Lee ◽  
Yoonkoo Kim ◽  
...  

TiO2 NRs which have a multi-function tasks such as protection from corrosion, antireflection and catalytic activities were grown in a 4-inch silicon for silicon-based solar water splitting.


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