bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Packaging Solution for High Density FCCSP Molding Warpage
Authors: Liu Shuai-Lin , Ye Ward , Wang Yu-Po , Wang Long-Yuan , Lin Fred 
Published: January 2020

Abstract
In recent years, the IC industry continues to drive demand in the consumer market, and more global sales of smart-phones, smart-watches and tablets have continued to grow. In order to continuously enhance high performance computing, the consumer products pursued began to integrate HBM (High Bandwidth Memory) and AI (Artificial Intelligence) to strong and powerful mainstream market.
With the shrinking use space pursued by consumer products, it is necessary to continuously develop lighter and thinner products, and under such product conditions, it seems that the risks and difficulties of advanced packaging technology will be expected. Due to the ministration application, the warpage issue is the most influential factor in the following development of packaging technology. In this paper, we would like to overcome the poor strip warpage, not only to choose the EMC material form CTE property, but to think about improving the warpage from the machine process. The residual stress generated by the molding process of thermosetting resins exerts serious influences upon the mechanical properties, so we use Laser area beam processing to reheat the EMC and use the vacuum suction to reshape the warpage deformation. In this case, we verify the laser radiation time and peak temperature control of different strip types (including molded, thermal taped and ball attached molded strip) and EMC wafer form. We succeed to improve the maximum strip warpage from 17 um to 1um; wafer form from 13um to 3.5um. This laser beam reshape technology is proven to solve the warpage significantly for high density assembly.
A Convenient and Reliable Method of Manufacturing Inclined Bulk Graphite for Measuring Thermal Conductivity With TDTR
Authors: Zhao Yu , Yu Hongyang , Sha Jingjie , Chen Yunfei 
Published: January 2020

Abstract
In this work, in order to study the thermal transport along arbitrary direction in bulk graphite, we develop a simple and convenient method to manufacture inclined bulk graphite applying Focused Ion beam (FIB). Then, we measure the thermal conductivity of inclined bulk graphite with the time-domain thermoreflectance (TDTR) technique and the measured results show that our processing method is reliable. Based on the TDTR measurement of inclined bulk graphite with a tilt angle of 90°, the in-plane thermal conductivity is on the order of 2030 Wm−1 K−1 and the cross-plane thermal conductivity is on the order of 5.5 Wm−1 K−1 at room temperature, which is close to the previously reported results. Our processing and measurement methods provide a new perspective on the study of the intrinsic mechanism of anisotropic thermal transport in anisotropic layered materials.
Optimizing Material Parameters for Better Formability of DQ Steel Pipe
Authors: Memon Shabbir , Mohammed Obaidur Rahman , Koppisetty D. V. Suresh , Lankarani Hamid M. 
Published: January 2020

Abstract
As Pipelines are subjected to bursting failure, the prediction of the burst capacities of corroded pipelines is of significant relevance to the pipeline industry. The Single mode deformation processes, most commonly used in laboratory evaluations like tensile test, may not realistically predict formability performance. Therefore, limit strains tests that use multiple deformation stages would better simulate actual material performance hence bulge test is widely used in pipeline industry for analyzing formability. The tube bulge test is an advanced testing material in which the tube is placed in a die cavity and is sealed from both the ends, the water is injected from the hole inside the sealing punch and hydraulic pressure is increased and the tube gets deformed at the center. The objective of this work is to utilize Taguchi coupled finite element computational methodology to determine the optimum material parameters to attain better formability without necking-splitting failure. To evaluate the dependence of the slope of the forming limit diagram on the material parameters, the simulation under various combinations of strain-hardening exponent (n), plastic strain ratio (r) and thickness of tube (t) is carried out and using thickness gradient criterion, the occurrence of necking i. e. forming limit strains during tube bulging is examined. By observing the optimum condition obtained for maximum plain strain it is concluded that higher the n, r and t more the limit strains will be. It is also observed that among n, r and t, n is the most prominent factor contributing on limit strains followed by r and t. The verification of optimum process parameters obtained through Taguchi technique is carried out using additive model and it is found that the observed value is well in agreement with the predicted value, the extra validation simulation is carried out to validate the Taguchi results.
An Assessment of the Validity of Quasi-Steady Analysis of Pressure Relief Valves
Authors: Doyle Christopher , Dempster William , Taggart Steven 
Published: January 2020

Abstract
In this paper, the validity of the commonly used quasi-steady design approach to pressure relief valves (PRV) is examined by comparing detailed steady state conditions of valve behavior directly with transient conditions. To achieve this, a PRV conforming to ASME VIII standards was modelled using the commercial computational fluid dynamics (CFD) package ANSYS FLUENT to account for transient fluid-structure interaction processes. Detailed steady state CFD simulations were conducted using quasi-steady assumptions and compared to high fidelity transient moving mesh simulations to allow the piston forces to be examined. The results indicated that noticeably different magnitudes can occur between steady state and transient simulations; highlighting the possibility of significant differences occurring between quasi steady designed valves and their ultimate performance. In this paper, a single operating condition is examined, using air at 10.3 barg, for a 5231BX refrigeration valve supplied by the Henry Group to highlight the main issues. Analysis has indicated that the differences in performance are generated by temporal, short lived vortices at the piston surface which influences the bulk flow features as the disc accelerates and decelerates; altering the net disc forces when compared to steady state conditions.
Genetic Algorithm Based Topology Optimization of Heat Exchanger Fins Used in Aerospace Applications
Authors: Mekki Bashir S. , Langer Joshua , Lynch Stephen 
Published: January 2020

Abstract
Topology Optimization (TO) in the design of structural components is commonly used and well explored. However, its usage in the design of complex thermo-fluid equipment used in aerospace applications is limited and relatively new. This is because the coupling between the fluid dynamics, heat transfer, and the shape is complex and nonlinear. Furthermore, the resulting geometry from a TO analysis is often very complex and difficult to manufacture due to the free forms that can occur. With the advent of Additive Manufacturing (AM), however, it has become possible to directly manufacture complex geometries. This study develops a new Genetic Algorithm (GA) based TO combined with Computational Fluid Dynamics (CFD) to produce optimized fin shapes for heat exchangers used in aerospace applications. To implement this approach, a rectangular shaped baseline fin geometry was created using voxel representation. An initial population is generated by mutating the baseline fin a random number of times. The CFD package OpenFOAM is then used to evaluate the performance of each design, after which the optimization algorithm is applied. The GA sorts the designs using a composite fitness function that is comprised of the overall heat transfer and pressure drop, and generates new generations based on mutation and carryover of top performing designs. The study also explores the sensitivity of the GA to the various GA parameters as well as the effect of varying flow Reynolds number. In general, as Reynolds number increases, the percent improvement in the optimum relative to the baseline increases, with potentially a 60% performance improvement. Overall, the approach enables generation of novel freeform designs that may open new performance space for heat transfer applications.
Joining Techniques for Novel Metal Polymer Hybrid Heat Exchangers
Authors: Kuntumalla Gowtham , Meng Yuquan , Rajagopal Manjunath , Toro Ricardo , Zhao Hanyang , Chang Ho Chan , Sundar Sreenath , Salapaka Srinivasa , Miljkovic Nenad , Shao Chenhui , Ferreira Placid , Sinha Sanjiv 
Published: January 2020

Abstract
In the United States, over 50% of the unrecovered energy from industrial processes is in the form of low-grade heat (&lt; 220°C). Materials and maintenance costs of common heat exchangers are typically too high to justify their usage. Polymers, though more affordable, are usually unsuitable for HX applications due to their low thermal conductivity (∼0.2 W/mK). Here, we show that metal-polymer hybrids may be attractive from both performance and cost perspectives. The use of polymers further increases the resistance to corrosion by sulfuric and carbonic acids often present in flue gases. An ongoing work explores different configurations of layered polyimide-copper macroscale hybrids for heat exchanger applications using numerical simulations. This paper explores a manufacturing pathway for producing such layered hybrid tubes that involves directly rolling and bonding tapes made of polymer and copper foil into tubes. A critical problem in the fabrication process is the bonding of metal and polymers. We explore approaches involving adhesives (epoxy, acrylic and silicone) for metal/polymer interfaces and direct welding (ultrasonic) for metal/metal interfaces that can be integrated into the manufacturing process. We report characterizations of the thermomechanical properties of these joining processes. This work paves the way for realizing cost-effective manufacturing of heat exchangers for low grade waste heat recovery.
Assessment of Parkinson’s Disease Tremor and Correlation Analysis With Applied Signal Processing
Authors: Zhu Na , Miller Nathaniel S. 
Published: January 2020

Abstract
Accurate measurement and assessment of Parkinson’s disease (PD) tremor is important for patients, clinicians, and researchers to track changes in disease progression and the effectiveness of therapeutic interventions. This study measured resting, postural, and kinetic tremor from patient’s most-affected hand with accelerometers and gyrometers, thus the linear and rotational motions in the x, y, z directions were obtained. Data were collected when patients were both ON and OFF their anti-PD medications. A bandpass filter was applied to extract raw tremor information and several signal processing algorithms were used to analyze the data in both time and frequency domains, including the correlations between motions at different directions. The results of medication effectiveness on PD tremor and the correlational analyses will be discussed.
Simulation of Body Force Impact on the Assembly Process of Aircraft Parts
Authors: Lupuleac Sergey , Smirnov Aleksandr , Churilova Maria , Shinder Julia , Zaitseva Nadezhda , Bonhomme Elodie 
Published: January 2020

Abstract
The manufacturing technology of some aircraft parts involves rotation of parts in assembly jig during the integration process. As the jig rotates, the gravity acting on the parts changes its direction. It can affect the residual gap between parts joined with temporary fasteners and lead to eccentricity of drilled holes for rivets. A numerical approach for simulation of airframe assembly process with account of this effect is discussed in the paper. The approach is based on reformulation of contact problem in terms of quadratic programming and introduction of special correction terms in the force vector. The developed approach is applied to evaluation of effect of assembly rotation on the contact quality.
Tribological Properties of Ammonium Protic Ionic Liquids As Additives in Polyalphaolefin for Steel-Steel Contact
Authors: Guo Hong , Iglesias Patricia 
Published: January 2020

Abstract
Around 23% of the world’s energy consumption results from rubbing contacts, in which 20% is used to overcome friction and 3% is due to wear and the consequent failure. The implementation of lubricants and effective lubricant additives are indispensable to reduce friction and wear of rubbing materials. Protic Ionic Liquids (PILs), which are easily obtained by proton transfer from a Brønsted acid to a Brønsted base, have shown great potential to be used as lubricants due to their structures and tunable properties. In this study, two kinds of novel PILs, bis(2-hydroxyethylammonium) succinate (DSu) and tri-[bis(2-hydroxyethylammonium)] citrate (DCi), were synthesized and tested as lubricant additives. The tribological behavior of the two PILs is studied as additives in 1 wt. % to a base synthetic lubricant (PAO) for steel-steel contact under different temperatures (room temperature and 100°C) and normal loads (3 N and 4 N) using a ball-on-flat reciprocating tribometer. When 1 wt. % of any PILs is added into PAO, friction is reduced compared to that with neat PAO at all temperatures and loads studied, and good anti-wear performance is also obtained under the higher temperature studied. Particularly, 1 wt. % DCi +PAO shows the best high-temperature tribological behavior under 4N, with friction and wear reductions of 33% and 35%, respectively.
Comparison of Dummy and Human Body Models in Automotive Side Impact Collisions According to the Regulatory Standards
Authors: Koppisetty D. V. Suresh , Hawaldar S. S. Akhil , Lankarani Hamid M. 
Published: January 2020

Abstract
Side-Impact car accidents are the second leading cause of fatalities in the United States. Regulatory standards have been developed for occupant protection in side impact car accidents using dummies or Anthropomorphic Test Devices (ATDs). Although the regulations are based on the use of ATDs, there might be differences between an actual human crash performance and that of a dummy crash performance. In recent years, technology has improved in such a way that crash scenarios can be modeled in various computational software. The human dynamic responses can be examined using active human body models including a combination of rigid bodies, finite elements, and kinematic joints, thus making them versatile to use in all crash test scenarios. In this study, the nearside occupants are considered as per regulatory standards set by National Highway Traffic Safety Administration (NHTSA). Vehicle side-impact crash simulations are carried out using LS-DYNA finite element (FE) software, and the occupant response simulations are obtained using MADYMO. Because the simulation of an entire FE model of a car and occupant is quite time-consuming and computationally expensive, a prescribed structural motion (PSM) technique has been utilized in this study and applied to the side-door panel with an occupant positioned in the driver seat of the car in MADYMO. Regular side-impact deformable barrier and pole test simulations are performed with belted and unbelted occupant models considering two different target vehicles namely — a mid-size sedan and a small compact car. Responses from the dummy and the human body models are compared in order to quantify differences between the two in side impacts. The results from this study indicate that human body model behavior is generally similar to that of dummy model in terms of kinematic responses. However, the corresponding injury parameters of the human model are typically higher than that of the dummy model.
Contact Analysis of Gear Trains Using Linear Complementarity Based Compliant Contact Model
Authors: Pathak Mangesh , Rakshit Sourav 
Published: January 2020

Abstract
The current computation models for gear contact analysis and wear prediction are mostly based on finite element analysis which consumes much computation time and effort. In this work, we adopt an alternative approach for gear contact analysis using linear complementarity. This approach was successfully applied to a pair of rigid spur gears and a planetary gear train (gears are considered as rigid bodies) in our previous work. In this paper, we extend our linear complementarity model to consider local deformation caused due to contact between gear teeth in mesh. Thus obtained linear complementarity model is applied to a pair of spur gears and a planetary gear train. A linear complementarity solver computes the contact forces between meshing teeth of gears. From the contact forces, sliding wear in gear teeth is predicted. Archard’s wear model is used for the wear prediction. Using this model, the contact forces are uniquely determined for the examples considered. The results of linear complementarity and finite element model for a pair of spur gears are compared. The linear complementarity model consumes much less computation time than the finite element model.
Developing of a Simscape Multibody Contact Library for Gothic Arc Ball Screws: A Three-Dimensional Model for Internal Sphere/Grooves Interactions
Authors: Bertolino Antonio Carlo , Jacazio Giovanni , Mauro Stefano , Sorli Massimo 
Published: January 2020

Abstract
The Simscape Multibody software is a set of libraries and mechanical modeling and simulation tools for use with Simulink®. For what concerns the contact library, currently it contains only the models to describe impacts between simple geometries, such as spheres, cylinders and planes. When this environment is intended to be used to simulate the 3D dynamics of a system with a complex geometry, such as a ball screw, the built-in blocks are not sufficient. This paper presents a new contact library, containing blocks specifically designed to handle the contacts between a sphere and the two gothic arc helical grooves of a ball screw, as well as the interaction between adjacent spheres. The developed blocks are exploited to create a first case study dynamic model of a single nut not preloaded ball screw in presence of internal backlash. The results highlight the superiority of this multibody approach with respect to the quasi-static or lumped parameters models in terms of extracted information and understanding of the internal mechanics.
Effect of Pore Density on Jet Impingement Onto Thin Metal Foams Under Intermediate Crossflow Scheme
Authors: Madhavan Srivatsan , Sambamurthy Vivek Subramaniam , Singh Prashant , Ekkad Srinath 
Published: January 2020

Abstract
Array jet impingement heat transfer onto thin metal foams of different pore densities has been experimentally investigated in the current study. Aluminum foams with high porosity (93%) and different pore densities of 5, 20 and 40 ppi are subjected to array jet impingement under an intermediate crossflow exit scheme. The jets are arranged such that the streamwise jet-to-jet spacing is x/dj = 8 and spanwise jet-to-jet spacing is y/dj = 4. Jet to target plate spacing was maintained at z/dj = 6 where ‘z’ is the distance between the jet plate and the target surface on which metal foams were installed. A steady state heat transfer technique has been used to obtain local heat transfer coefficients along the streamwise direction. It is observed that heat transfer enhancement levels increase as pore density increases. An enhancement of 50–100% over the baseline case of impingement onto smooth surface is obtained over the flow range tested (3000 &lt; Redj &lt; 12000). At a constant pumping power of 40 W, an enhancement of 26–33% is obtained for the different pore densities tested.
High Voltage Energy Harvesting From Embedded PVDF Harvester Inspired From Metamaterial Design
Authors: Saadatzi Mohammadsadegh , Saadatzi Mohammad Nasser , Banerjee Sourav 
Published: January 2020

Abstract
In the current study, a novel multi-frequency, vibration-based Energy Harvester (EH) is proposed, numerically verified, and experimentally validated. The structural design of the proposed EH is inspired from an inner-ear, snail-shaped structure. In the past decade, scavenging power from environmental sources of vibration has attracted a lot of researchers to the field of energy harvesting. High demands for cleaner and renewable energy sources, limited sources of electrical energy, high depletion rates of nonrenewable sources of energy, and environmental concerns have urged researchers to investigate new structures called Metamaterial energy harvesters to harness electrical potential. The proposed EH is a metamaterial structure which has a Polyvinylidene Difluoride (PVDF) structure incapsulated in an aluminum frame and follows the physics of a mass-in-mass Phononic crystal structure. The PVDF snail-shaped structure is encapsulated inside a silicone matrix with a specific material property. This EH reacts to the environmental vibrations and the encapsulating silicone entraps the kinetic energy within its structure. The EH unit cell behaves as a negative mass in the vicinity of its resonance frequencies. In this paper, the dynamic behavior of the proposed EH is numerically modeled in COMSOL Multiphysics and, subsequently, validated experimentally using a unit cell fabricated in-house.
Synthesis of Flexure Based Translational Springs
Authors: Chattopadhyay Abhijit Ashish , Zhou Hong 
Published: January 2020

Abstract
Translational springs are employed to generate desired force-displacement relationships. Conventional translational springs utilize elastic deformations of coiled spring strips to fulfill their functions. The one-dimensional motion of a conventional translational spring is produced by the three-dimensional deformation of its coiled spring strip, which is bending plus twisting of the coiled spring strip. Different from conventional translational springs, flexure based translational springs usually have simple planar monolithic structures, and are convenient to manufacture and maintain. The translation of a flexure based translational spring is from the two-dimensional elastic or recoverable deformations of its planar flexible members. The flexure based translational springs synthesized in this research are required to endure large input translations. Because of large deformation and geometric nonlinearity, flexure based translational springs face difficulties that include parasitic drift, spring stiffness deviation, and high stress in the deformed springs. The research of this paper is motivated by surmounting these difficulties. Flexure based translational springs with different arrangements are synthesized to eliminate parasitic drifts and have desired spring rates and reasonable maximum stress.
Automatic Design in Matlab Using PDE Toolbox for Shape and Topology Optimization
Authors: Sun Yilun , Xu Lingji , Yang Jingru , Lueth Tim C. 
Published: January 2020

Abstract
In this paper, we present a novel concept of using Matlab’s Partial Differential Equation (PDE) Toolbox to achieve shape and topology optimization during the automatic mechanical design process. In our institute, we are developing a toolbox called Solid Geometry (SG) Library in Matlab to achieve automatic design of medical robots and mechanisms. The entire design process is performed in one developing environment without additional data input and output. And those robots and mechanisms can be quickly manufactured by different kinds of 3D printers. Recently, we have also integrated the shape and topology optimization techniques into our automatic design process by using the PDE Toolbox of Matlab for finite element analysis because of its high efficiency and compactness. For optimization algorithms, we have already implemented two bionic structural optimization methods called Computer Aided Optimization (CAO) and Soft Kill Option (SKO) to optimize the stress distribution in the structure. Since the complicated material layout in the optimization results can be easily realized by the 3D printing technology, the mechanical performance of our medical robots and mechanisms can be greatly improved with the work presented in this paper.