Shock Angle Variation on High-G Impact Reliability of Electronics Potted Assemblies

In this research, super-low specific speed centrifugal pump ( ns = 25, Chinese units: ns = 3.6 nQ1/2/ H3/4) is studied. The effect of the front streamline wrapping angles variation (135°, 139° and 145°) of the turbine on energy performance is considered. The pressure pulsation, interior and exterior noise characteristics and the performance of the impeller are thoroughly evaluated both experimentally and numerically. The pump has been modeled by means of computational fluid dynamics code of commercial software ANSYS CFX 11.0 to estimate energy performance and pressure pulsation. Boundary element method and finite element method are used to investigate the interior and exterior noise characteristics of the centrifugal pump by varying the front sweep angle. The front sweep angle variation was found to have insignificant influence on centrifugal pump performance characteristics. However, it influences fluid hydrodynamics around the volute tongue. In addition, the decreasing of the front streamline sweep angle slightly reduces the sound pressure level for the exterior acoustics, but the radiation distribution of the acoustic field does not change. In its turn, the modified trailing edge of the blades can reduce the peak value of the superposition decreasing the pressure pulsations at the blade passing frequency and its harmonic frequencies.

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Impact reliability estimation of lead free solder joint with IMC layer

Thin Solid Films ◽

10.1016/j.tsf.2009.02.039 ◽

2009 ◽

Vol 517 (14) ◽

pp. 4255-4259 ◽

Cited By ~ 12

Author(s):

Jong-Min Kim ◽

Seung-Wan Woo ◽

Yoon-Suk Chang ◽

Young-Jin Kim ◽

Jae-Boong Choi ◽

...

Keyword(s):

Solder Joint ◽

Reliability Estimation ◽

Lead Free ◽

Lead Free Solder ◽

Free Solder ◽

Impact Reliability

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Investigating the Effect of Interface Morphology in Adhesively Bonded Composite Wavy-Lap Joints

Journal of Composites Science ◽

10.3390/jcs5010032 ◽

2021 ◽

Vol 5 (1) ◽

pp. 32

Author(s):

Roya Akrami ◽

Shahwaiz Anjum ◽

Sakineh Fotouhi ◽

Joel Boaretto ◽

Felipe Vannucchi de Camargo ◽

...

Keyword(s):

Mechanical Behavior ◽

Composite Structures ◽

Failure Modes ◽

Mechanical Performance ◽

Tensile Load ◽

Lap Joints ◽

Load Level ◽

Displacement Curve ◽

Interface Morphology ◽

Angle Variation

Joints and interfaces are one of the key aspects of the design and production of composite structures. This paper investigates the effect of adhesive–adherend interface morphology on the mechanical behavior of wavy-lap joints with the aim to improve the mechanical performance. Intentional deviation from a flat joint plane was introduced in different bond angles (0°, 60°, 90° and 120°) and the joints were subjected to a quasi-static tensile load. Comparisons were made regarding the mechanical behavior of the conventional flat joint and the wavy joints. The visible failure modes that occurred within each of the joint configurations was also highlighted and explained. Load vs. displacement graphs were produced and compared, as well as the failure modes discussed both visually and qualitatively. It was observed that distinct interface morphologies result in variation in the load–displacement curve and damage types. The wavy-lap joints experience a considerably higher displacement due to the additional bending in the joint area, and the initial damage starts occurring at a higher displacement. However, the load level had its maximum value for the single-lap joints. Our findings provide insight for the development of different interface morphology angle variation to optimize the joints behavior, which is widely observed in some biological systems to improve their performance.

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SIMULATION OF THE DYNAMICS OF CASSAVA STEM CUTTINGS ON AN INCLINED WOOD SURFACE

Journal of Natural Sciences Engineering and Technology ◽

10.51406/jnset.v14i2.1758 ◽

2018 ◽

Vol 14 (2) ◽

pp. 85-97

Author(s):

I A OLA ◽

O O AREMU ◽

A A ADERINLEWO ◽

E S.A AJISEGIRI ◽

P O AIYEDUN ◽

...

Keyword(s):

Wood Surface ◽

Great Influence ◽

Stem Cuttings ◽

Flow Properties ◽

Angle Variation ◽

Predictive Parameters ◽

Major Transition ◽

Cassava Stem ◽

The Tropics ◽

Precision Machines

Development of precision machines to handle some of the field activities involved in the cultivation of cassava is a highly welcomed project among young enterprising farmers who are keen in resolving the posterity of their wellbeing as a big time farmer. Mechanization of cassava in the tropics is grossly hampered by lack of extensive knowlegde on the behaviour, physical properties of cassava stems and parameters that have great influence on the handling of the stems during cultivation, hence the limita-tion of advancing the present semi-automatic planter to fully automated one is still a mirage in the tropics. This paper presents the flow properties of cassava cuttings that can lend it to proper handling in a metering machine. A variable inclined wood surface rig with an ejection outlet was used to study the properties of the stem. Measured cassava stem predictive parameters; diamater, lentgh,weight; angle variation on the rig; response parameters; percentage ejected, percentage sliding through, forces acting on stems were obtained. The results from the study could be used to predict acurately the exact dynamics of a given stem isolated from the bulk of stem cuttings stacked in the metering hopper. Models to predict the flow properties of the stems were obtained; further simulation of the dynamics was embarked upon using MATLAB software. A major transition zone of stem characteris-tics per pecentage sliding to ejection occurred within the range of angles of 150 -300. This might be a favourable angular zone for isolating the stems from the bulk mass while the effectively isolated stems can be metered appropriately by another mechanism in the process of developing a metering device for cassava stem cuttings.

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Interface Energy-driven Indium Whisker Growth on Ceramic Substrates

10.21203/rs.3.rs-250820/v1 ◽

2021 ◽

Author(s):

Shuai Li ◽

Yushuang Liu ◽

Peigen Zhang ◽

Yan Zhang ◽

Chengjie Lu ◽

...

Keyword(s):

Whisker Growth ◽

Interface Energy ◽

Mitigation Strategy ◽

Max Phase ◽

Number Density ◽

Ceramic Substrates ◽

Liquid Indium ◽

Reliability Of Electronics

Abstract The mechanism behind spontaneous growth of metal whiskers is essential to develop lead-free whisker mitigation strategy for the sake of long-term reliability of electronics, and has been sought for several decades. However, a consensus about it still lacks, and a host of factors influencing the phenomenon have been investigated, but the role of interface energy has not been paid adequate attention. In this study, the whisker growth propensities of ball-milled Ti2InC/In and non-MAX phase TiC/In and SiC/In are comparatively studied in the terms of the wettability, thermal behavior and crystal structures. The wetting angles of indium with Ti2InC, TiC, and SiC (144.4°, 155.7°, and 142.2°, respectively) are large and quite close, indicating the poor wettability between liquid indium and the three ceramics. The thermal behaviors of all the three systems have obvious changes after ball milling. The number density of indium whiskers on ball-milled Ti2InC are significantly greater than those on the TiC and SiC substrates, which is explained based on interface energy and the crystal structure difference of the ceramic substrates.

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