Predicting Deformation and Strain Behavior in Circuit Board Bend Testing

2012 ◽  
Author(s):  
Ronen Aniti
Keyword(s):  
Circuit Board ◽  
Bend Testing ◽  
Strain Behavior

The IC in the Flexible Hybrid Electronics Technology: Flexibility and Bend Testing

2017 ◽  
Vol 2017 (1) ◽  
pp. 000103-000108 ◽  
Author(s):  
Val R. Marinov
Keyword(s):  
Flexural Strength ◽  
Empirical Test ◽  
Critical Issue ◽  
Test Method ◽  
Circuit Board ◽  
Radius Of Curvature ◽  
Bend Testing ◽  
Die Geometry ◽  
Silicon Chips ◽  
Semi Empirical

Abstract Flexible Hybrid Electronics (FHE) can be described as thinned, flexible silicon chips packaged on flexible circuit board (FCB) with printed conductors and passives. The flexibility of ICs can be achieved only if the thickness of the silicon is reduced to 50μm or less. The bend testing of the ultra-thin dies is a critical issue in the FHE technology as it allows to establish the fundamental relationships between the die flexural strength, die geometry, and the methods for thinning and dicing the silicon. The conventional bend tests are not adequate for testing ultra-thin dies. Presented is a semi-empirical test method, which allows for the estimation of the flexural strength of the highly compliant ultra-thin dies. The limiting Radius of Curvature (RoC) is an important parameter for the FHE device since it accounts for the bending characteristics of the entire FHE device, not only the IC. Presented is a simple analytical approach that allows to estimate the minimum RoC for an FHE assembly.

Blue Stream Collapse Test Program

2005 ◽  
Author(s):  
D. DeGeer ◽  
C. Timms ◽  
V. Lobanov
Keyword(s):  
Black Sea ◽  
Wall Thickness ◽  
Large Diameter ◽  
External Pressure ◽  
Combined Loading ◽  
The Black Sea ◽  
Pipe Material ◽  
Test Program ◽  
Bend Testing ◽  
Strain Behavior

The Blue Stream pipeline is a gas transmission line delivering natural gas from the Russian grid. across the Black Sea, to Turkey. The submarine portion of this pipeline consists of a pair of 24-inch diameter, 31.8 mm wall thickness, API grade X65 pipelines running almost 400 km along the floor of the Black Sea. Over one half of the submarine pipeline lies at a water depth of more than 2000 metres, with the deepest portion of the line reaching a depth of 2150 metres. First gas was supplied through the lines in February of 2003. There were numerous engineering obstacles facing this technically challenging pipeline undertaking. including a lack of heavy-wall, large diameter pipe experimental data to support the pipeline design. Recognizing this need, PeterGaz commissioned a collapse test program during the preliminary engineering phase of the project to generate these data and to gain a better understanding of pipe behavior under combined loading conditions. Numerous full-scale tests were performed on prototype pipe samples, including external pressure testing, combined external pressure and bend testing, and bend testing. Hundreds of material coupon tests were also performed to characterize material stress strain behavior around the circumference of the pipe, through the wall thickness of the pipe, and before and after UOE manufacturing. Tests were also performed to quantify the strength recovery of thermally treated pipe material resulting from the pipe coating process. This paper presents the results of this experimental work and provides some comparisons to collapse predictions.

Bending Simulation of BGA SMT Assemblies and Application to System Level Drop Simulation

2005 ◽  
Author(s):  
Doug Carroll ◽  
Marc Zampino ◽  
Kinzy Jones
Keyword(s):  
Solder Joint ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Circuit Board ◽  
System Level ◽  
Bending Test ◽  
Beam Model ◽  
Strain Behavior ◽  
Order Of Magnitude ◽  
Dynamic Bending

This paper will examine the displacement and strain behavior of solder joints during static and dynamic bending. Simulation has shown that four point dynamic bending test result in a higher accumulation of plastic strain than static bending at equivalent board strains. This is important as the yielding and failure of lead-free solder joints occurs primarily at the joint package interface. Solder joint strains are on the order of magnitude higher than printed circuit board (PCB) bending strains at the edge of the package. Additionally, a method for using solder joint stretch has been developed for measuring joint response. Utilizing the concept of solder stretch, a technique for using equivalent beam models for the solder joints in a system level drop will be introduced. Results for three different beam model strategies will be given. The results show these techniques are valid and their use will greatly increase the ability to determine package impact reliability during the design stages.

Environmental microscopy of capillary stress-induced strain behavior in ambient-pressure aerogels

1996 ◽  
Vol 54 ◽  
pp. 850-851
Author(s):  
Sudeep M. Rao ◽  
Joshua Samuel ◽  
Sai S. Prakash ◽  
C. Jeffrey Brinker
Keyword(s):  
Silica Aerogel ◽  
Ambient Pressure ◽  
Drying Shrinkage ◽  
Pore Filling ◽  
Silica Network ◽  
Strain Behavior ◽  
Partially Saturated ◽  
Capillary Stress ◽  
Wetting Liquid ◽  
Aerogel Films

Ambient pressure silica aerogel thin films have recently been prepared by exploiting reversible drying shrinkage caused by derivatization of the internal gel surface. Aerogels have porosities of upto 99.9% and due to the small size of the pores (few nanometers), large capillary stresses are produced in gels that are partially saturated with a wetting liquid. As a result of these capillary stresses, the flexible silica network undergoes strain which has been observed using environmental microscopy. This technique allows variation of the equilibrium vapor pressure and temperature, and a simultaneous monitoring of the deformation of the unconstrained film thickness. We have observed >600% deformation during the pore-filling and pore-emptying cycles. In this presentation, we discuss the unique stress-strain behavior of these films.Ref.: Sai S. Prakash, C. Jeffrey Brinker, Alan J. Hurd & Sudeep M. Rao, "Silica aerogel films prepared at ambient pressure by using surface derivatization to induce reversible drying shrinkage", Nature. Vol. 374, 30 March, 1995, 439-443.

Effect Of Elevated Temperatures On Complete Concrete Deformation Diagrams

2019 ◽  
pp. 9-14
Keyword(s):  
Experimental Data ◽  
Elastic Modulus ◽  
Elevated Temperatures ◽  
Peak Load ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Compression Tests ◽  
Strain Behavior ◽  
Different Temperatures ◽  
Deformation Diagrams

The analysis of the previous results of the study on concrete stress-strain behavior at elevated temperatures has been carried out. Based on the analysis, the main reasons for strength retrogression and elastic modulus reduction of concrete have been identified. Despite a significant amount of research in this area, there is a large spread in experimental data received, both as a result of compression and tension. In addition, the deformation characteristics of concrete are insufficiently studied: the coefficient of transverse deformation, the limiting relative compression deformation corresponding to the peak load and the almost complete absence of studies of complete deformation diagrams at elevated temperatures. The two testing chambers provided creating the necessary temperature conditions for conducting studies under bending compression and tension have been developed. On the basis of the obtained experimental data of physical and mechanical characteristics of concrete at different temperatures under conditions of axial compression and tensile bending, conclusions about the nature of changes in strength and deformation characteristics have been drawn. Compression tests conducted following the method of concrete deformation complete curves provided obtaining diagrams not only at normal temperature, but also at elevated temperature. Based on the experimental results, dependences of changes in prism strength and elastic modulus as well as an equation for determining the relative deformation and stresses at elevated temperatures at all stages of concrete deterioration have been suggested.

Characteristics of Radiated Emission from a Printed Circuit Board with a Slit

2012 ◽  
Vol 132 (6) ◽  
pp. 404-410 ◽  
Author(s):  
Kenichi Nakayama ◽  
Kenichi Kagoshima ◽  
Shigeki Takeda
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Radiated Emission

Development of High Permeability Core Materials for Embeddable Inductors in Flexible Organic Substrates

2003 ◽  
Vol 769 ◽  
Author(s):  
C. K. Liu ◽  
P. L. Cheng ◽  
S. Y. Y. Leung ◽  
T. W. Law ◽  
D. C. C. Lam
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Circuit Board ◽  
Organic Substrates ◽  
Circuit Boards ◽  
High Permeability ◽  
Electrical Measurements ◽  
Different Temperatures ◽  
Spiral Inductors ◽  
Ceramic Tape

AbstractCapacitors, resistors and inductors are surface mounted components on circuit boards, which occupy up to 70% of the circuit board area. For selected applications, these passives are packaged inside green ceramic tape substrates and sintered at temperatures over 700°C in a co-fired process. These high temperature processes are incompatible with organic substrates, and low temperature processes are needed if passives are to be embedded into organic substrates. A new high permeability dual-phase Nickel Zinc Ferrite (DP NZF) core fabricated using a low temperature sol-gel route was developed for use in embedded inductors in organic substrates. Crystalline NZF powder was added to the sol-gel precursor of NZF. The solution was deposited onto the substrates as thin films and heat-treated at different temperatures. The changes in the microstructures were characterized using XRD and SEM. Results showed that addition of NZF powder induced low temperature transformation of the sol-gel NZF phase to high permeability phase at 250°C, which is approximately 350°C lower than transformation temperature for pure NZF sol gel films. Electrical measurements of DP NZF cored two-layered spiral inductors indicated that the inductance increased by three times compared to inductors without the DP NZF cores. From microstructural observations, the increase is correlated with the changes in microstructural connectivity of the powder phase.

Ultra-Small Reader/Writer with Multiple Contactless Interfaces on a Flexible Circuit Board

2009 ◽  
Vol E92-B (9) ◽  
pp. 2992-2995
Author(s):  
Hideaki YAMAMOTO ◽  
Minoru IKEDA ◽  
Yasuhiro HOSODA
Keyword(s):  
Circuit Board
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