Designing Surface-Mounted Components for High Reliability

1994 ◽  
Vol 116 (3) ◽  
pp. 232-239
Author(s):  
J. Rasty ◽  
W. Kolarik ◽  
B. Chen
Keyword(s):  
Printed Circuit Board ◽  
Signal To Noise Ratio ◽  
High Reliability ◽  
Design Procedure ◽  
Circuit Board ◽  
Vibration Direction ◽  
Finite Element Software ◽  
Analysis System ◽  
Von Mises ◽  
Von Mises Stresses

Recent emphasis of the Department of Defense (DOD) on the reliability and integrity of avionics has spurred a new wave of research on this subject. This paper presents the results of a parametric investigation conducted to study the effect of vibration direction, boundary conditions, stiffeners and/or point supports, lead type, lead height, and the layout of the components on the natural frequencies and stresses exerted on a typical printed circuit board (PCB) used in avionics. The “robust design” procedure was adopted using a series of computer-simulated experiments. A finite element software, EMRC-FEAP, was utilized to estimate the maximum von Mises stresses within the critical leads, while the statistical analysis system (SAS) software was employed to analyze the natural frequency responses of the system and the signal-to-noise ratio (SNR) of the stresses induced at critical leads.

scholarly journals Affordable Thin Lens Using Single Polarized Disparate Filter Arrays for Beyond 5G toward 6G

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3982
Author(s):  
Inseop Yoon ◽  
Seongwoog Oh ◽  
Jungsuek Oh
Keyword(s):  
Manufacturing Process ◽  
Printed Circuit Board ◽  
Design Procedure ◽  
Circuit Board ◽  
Process Conditions ◽  
60 Ghz ◽  
Thin Lens ◽  
Gain Enhancement ◽  
Unit Cells ◽  
Pcb Manufacturing

This paper proposes a novel design approach for a thin lens with the aim of overcoming fineness limits in the commercial millimeter wave printed circuit board (PCB) manufacturing process. The PCB manufacturing process typically does not allow the fabrication of metallic patterns with a gap and width of less than 100 μm. This hampers expanding thin lens technology to 5G commercial applications, especially when such technology is considered for 60 GHz or higher frequency, which requires a finer gap and width of metallic traces. This paper proposes that problematic process conditions can be mitigated when a lens is designed by establishing single-polarized lumped element models where larger capacitance and inductance values can be obtained for the same patch and grid unit cells. While the proposed design technique is more advantageous at higher target frequencies, a 60 GHz application and a wireless backhaul system is selected because of a limited range of frequencies that can be measured by an available vector network analyzer. The required gap or width of metallic traces can be widened significantly by using the proposed single-polarized unit cells to acquire the same in-plane capacitance or inductance. This enables the lens operating at higher-frequency under the process limits in fabricable fine traces. Finally, the effectiveness of the simulated design procedure is demonstrated by fabricating a 60 GHz thin lens that can achieve a gain enhancement of 16 dB for a 4 × 4 patch antenna array with a gain of 16.5 dBi.

Damage and Failures of CGA/BGA Assemblies Under Thermal Cycling and Dynamic Loadings

2013 ◽  
Author(s):  
Reza Ghaffarian
Keyword(s):  
Thermal Cycling ◽  
Mechanical Loading ◽  
Test Data ◽  
Printed Circuit Board ◽  
High Reliability ◽  
Circuit Board ◽  
Design Parameters ◽  
Mechanical Shock ◽  
Space Applications ◽  
High Processing

Commercial-off-the-shelf column/ball grid array packaging (COTS CGA/BGA) technologies in high-reliability versions are now being considered for use in high-reliability electronic systems. For space applications, these packages are prone to early failure due to the severe thermal cycling in ground testing and during flight, mechanical shock and vibration of launch, as well as other less severe conditions, such as mechanical loading during descent, rough terrain mobility, handling, and ground tests. As the density of these packages increases and the size of solder interconnections decreases, susceptibility to thermal, mechanical loading and cycling fatigue grows even more. This paper reviews technology as well as thermo-mechanical reliability of field programmable gate array (FPGA) IC packaging developed to meet demands of high processing powers. The FPGAs that generally come in CGA/PBGA packages now have more than thousands of solder balls/columns under the package area. These packages need not only to be correctly joined onto printed circuit board (PCB) for interfacing; they also should show adequate system reliability for meeting thermo-mechanical requirements of the electronics hardware application. Such reliability test data are rare or none for harsher environmental applications, especially for CGAs having more than a thousand of columns. The paper also presents significant test data gathered under thermal cycling and drop testing for high I/O PBGA/CGA packages assembled onto PCBs. Damage and failures of these assemblies after environmental exposures are presented in detail. Understanding the key design parameters and failure mechanisms under thermal and mechanical conditions is critical to developing an approach that will minimize future failures and will enable low-risk insertion of these advanced electronic packages with high processing power and in-field re-programming capability.

Advanced Materials for Printed Circuit Boards

1987 ◽  
Vol 108 ◽  
Author(s):  
David Wei Wang
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
High Reliability ◽  
Circuit Board ◽  
Advanced Materials ◽  
Impregnation Method ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Worldwide Production ◽  
Board Industry

The printed circuit board is an integral part of the electronic packaging hierarchy. Its use began more than 40 years ago, and the demand for printed circuit boards has increased in parallel with the growth of the electronics industry.[1] According to a recent forecast, the worldwide production of printed circuit boards will reach to over 19 billion U.S. dollars' worth by 1990.[2] With continuing demands for more interconnections, the multilayer circuit board industry is experiencing its fastest growth rate. Boards with more than 20 inner planes of circuitry are being manufactured with high reliability.Based on dollar values, more than 90% of the circuit boards produced are in the rigid board category, where starting materials are based on thermosetting prepregs produced by a solution impregnation method. This article is a review of materials currently used in rigid composites.

Temperature and Stress Examinations on Pistons for Damage Prevention and Efficiency Enhancement: Carbon/Carbon Composite Piston vs Conventional Aluminum Pistons

2015 ◽  
Author(s):  
Murat Kaan ◽  
M. Halidun Kelestemur
Keyword(s):  
Thermal Effects ◽  
Coefficient Of Thermal Expansion ◽  
Cylinder Liner ◽  
Carbon Composite ◽  
Efficiency Enhancement ◽  
Connecting Rod ◽  
Finite Element Software ◽  
Conductivity Property ◽  
Von Mises ◽  
Von Mises Stresses

By identifying well-known failures in pistons, uniquely on skirt area where overlapping with cylinder mainly occurs and causing pistons to fail are investigated. Hence, aim of this paper is to compare two different pistons by analyzing their temperature and stress/strain distributions on specific areas, specifically crown and skirt. By considering the unique properties of carbon, mainly the low coefficient of thermal expansion, density and toughness; expectations in carbon/carbon pistons seemed highly promising compared to conventionally used aluminum pistons. Furthermore, necessary analyses are made by a finite element software package, AbaQus. It is observed that the usage of carbon/carbon composite as a material for pistons shows a high thermal durability which is crucial for necessary cooling stage than aluminum due to its low thermal conductivity property. It is also shown that compared to aluminum, carbon/carbon pistons are 30% lighter in weight, more resistible to mechanical loadings such being pressure, inertial loadings, side forces, and thermal effects. Carbon/carbon composite piston’s tolerance to higher Von Mises stresses around 489 MPa and temperatures up to 664 °C shows a clear superiority when compared to aluminum. Carbon/carbon composite pistons are also much more relevant to be used in an engine for weight reduction and increasing clearance tolerance down to 0.01 mm between the piston and cylinder liner which indirectly reduces the mass of components and directly reduces side forces by a longer connecting rod usage allowance.

Research of Reliable Design of Printed Circuit Board Suited for Smart Grid

2012 ◽  
Vol 229-231 ◽  
pp. 1503-1506
Author(s):  
Chuan Liu ◽  
Zai Chao Huang ◽  
Peng Wu ◽  
Zhi Gang Wu ◽  
Lei Chen
Keyword(s):  
Smart Grid ◽  
Communication System ◽  
Energy Demand ◽  
Printed Circuit Board ◽  
High Reliability ◽  
Circuit Board ◽  
Self Healing ◽  
Stage Of Development ◽  
Pcb Design ◽  
Smart Grid Communication

Electric utilities faced with the prospect of increasing customer rates are seeking solutions to challenges presented by rising global energy demand, aging infrastructure, increasing fuel costs and renewable portfolio standards in light of climate change. Many consider Smart Grid to be one such solution. The most two significant characteristics of Smart Grid are self-healing ability and high reliability. As the bottom stage of development of Smart Grid communication system, the signal quality and self reliability of PCB design directly influence the entire performance of the communication system. This article focuses on analyzing reliable PCB design suited for Smart Grid communication system from power supply, thermal dispersion and trace routing.

scholarly journals A lamination-based piezoelectric insole gait analysis system for massive production for Internet-of-health things

2020 ◽  
Vol 16 (3) ◽  
pp. 155014772090543
Author(s):  
Yanning Dai ◽  
Yuedong Xie ◽  
Junliang Chen ◽  
Shuaibo Kang ◽  
Lijun Xu ◽  
...  
Keyword(s):  
Nervous System ◽  
Gait Analysis ◽  
Printed Circuit Board ◽  
Disease Diagnosis ◽  
Circuit Board ◽  
Detection Sensitivity ◽  
System Disease ◽  
Flexible Printed Circuit ◽  
Complex Integration ◽  
Analysis System

Gait analysis has been proved to be a powerful and efficient means for health monitoring. Variety of nervous system diseases and emergencies can be detected by interpreting plantar stress distributions. Among gait analysis techniques, piezoelectric insole architectures receive boosting attentions due to its convenience for users to wear and its long-term and real-time monitoring ability. However, the complex integration of piezoelectric insole architecture limits its successful use for massive production for the Internet-of-health things (IoHT). Hence, in this article, we present a flexible printed circuit board and lamination-associated technique, which presents high detection sensitivity at 0.1 N, satisfying the need for assisting nervous system disease diagnosis, and showing strong potential for commercialization.

Numerical simulations on static and dynamic response of full-scale mast structures for H-Darrieus wind turbine

2020 ◽  
pp. 0309524X2091731
Author(s):  
Fateh Ferroudji ◽  
Lakhdar Saihi ◽  
Khayra Roummani
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Manufacturing Cost ◽  
Vertical Axis Wind Turbine ◽  
Structural Dynamic ◽  
Finite Element Software ◽  
Von Mises ◽  
Von Mises Stresses

Mast structure is one of the most important parts of a vertical-axis wind turbine which supports generator and rotor and represents one-third of the overall costs in the production of a standard wind turbine (approximately 30%). All this may cause significant economic and physical losses when it is damaged or collapsed. The purpose of this research is to investigate numerically the static strength and structural dynamic responses of 10-kW vertical-axis wind turbine masts subjected to the aerodynamic and gravity loadings (according to the IEC 61400-2:2006 and EN 1991-1-4:2005 standards) using the SolidWorks finite element software. Mast structures with four different heights (12, 14, 16, and 18 m) and three various outer diameters (0.6, 0.7, and 0.8 m), in each height configuration, were evaluated. These analyses were performed to identify the stiffness, resistance, reliability, and natural frequency stiffness requirements within the mast structures, in order to save manufacturing cost. Based on static analysis, no structural failure is predicted for all masts during wind turbine operation according to maximum von Mises stresses at the bottom of the mast and maximum total deflections on the top of the mast. In addition, the dynamic parameters of these 12 models of masts have been studied to obtain the natural frequencies and corresponding mode shapes. Finally, the recommendations to avoid resonance and design strategy for each mast model are discussed.

High Reliability Pb-Free Printed Circuit Board Assembly

2010 ◽  
Vol 450 ◽  
pp. 9-12
Author(s):  
S.D.T. Weller ◽  
I.P. Jones ◽  
Ian M. Fox ◽  
Terry Hirst
Keyword(s):  
Process Parameters ◽  
Printed Circuit Board ◽  
High Reliability ◽  
Electroless Nickel ◽  
Cycling Performance ◽  
Circuit Board ◽  
Optimum Process ◽  
Printed Circuit Board Assembly ◽  
Circuit Board Assembly ◽  
Lead Free Solders

The solderability and reliability of SnAgCu and SnAgCuSbBiNi lead-free solders were assessed against SnPbAg solder on a range of PCB finishes. A novel solderability test has been developed to assess the solder system’s ability to realign when a deliberately inaccurate solder stencil printing process was applied. This has shown to be an excellent way to compare PCB finishes and solders, as well as define process parameters. Electroless Nickel Immersion Gold (ENIG) finish proved to give the best solderability and the optimum process parameters were also found. SnPbAg solder has shown superior thermal cycling performance compared to SnAgCu.

scholarly journals Optimal design of the flywheel using nature inspired optimization algorithms

2018 ◽  
Vol 3 (1) ◽  
pp. 490-499 ◽  
Author(s):  
Prem Singh ◽  
Himanshu Chaudhary
Keyword(s):  
Optimal Design ◽  
Kinetic Energy ◽  
Design Procedure ◽  
Particle Swarm Algorithm ◽  
Jaya Algorithm ◽  
B Spline ◽  
Spline Curve ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Cubic Spline Curve

Abstract This paper presents the optimal design procedure of a flywheel using a cubic B-spline curve. The flywheel plays a vital role in storing kinetic energy in modern machines. The kinetic energy evaluates the performance of the flywheel. In order to improve the kinetic energy of a flywheel, a shape optimization model of the flywheel, with maximization of kinetic energy, is formulated using a cubic spline curve under the constraints of the mass of flywheel, and the maximum value of Von Mises stresses at all points along the radial direction. The Von Mises stresses at all points are determined using the two-point boundary value differential equation. The control points of the cubic B-spline curve are taken as design variables. Then the formulated problem is solved using particle swarm algorithm (PSO), genetic algorithm (GA), and Jaya algorithm. The proposed approach is applied to the flywheel of an agricultural thresher machine. It is found that the Jaya algorithm gives better results compared to the other algorithms. The optimized shape of the flywheel is simulated using MSC ADAMS software.

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