bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large Eddy Simulation of Isotropic Decaying Turbulence With Structured and Unstructured Grid Finite Volume Methods
Authors: Dailey Lyle D. , Simons Todd A. , Pletcher Richard H. 
Published: July 2023

Abstract
The performance of finite volume methods to obtain the large eddy simulation of homogeneous, isotropic, decaying turbulence in structured and unstructured grids has been studied. This simple flow was used for preliminary analysis of finite volume methods before application to more complex geometries. Both the Smagorinsky subgrid-scale model and the dynamic subgrid-scale model were evaluated.
The study has shown that both the structured and unstructured grid approaches work well with the Smagorinsky model. As expected, the structured grid scheme was slightly more accurate than the unstructured grid scheme. The dynamic model has also been shown to work well with the structured and unstructured grids.
Two- and Three-Dimensional Laminar Flows Between Disks Corotating in a Fixed Cylindrical Enclosure
Authors: Iglesias Immaculada , Humphrey Joseph A. C. 
Published: July 2023

Abstract
A numerical investigation is performed for the constant-property laminar flow of air in the space between a pair of disks clamped coaxially on a central hub and corotating in a stationary cylindrical enclosure. Both two- and three-dimensional flow conditions are examined in relation to the interdisk spacing, H, and the disk angular velocity, Ω. Two interdisk spacings are considered, corresponding to aspect ratios Γ = 0.186 and 0.279 [with Γ = H/(R2 + a – R1), where R2 is the disk radius, a is the disk rim-enclosure wall clearance, and R1 is the hub radius]. A range of rotational speeds encompassing the transition from axisymmetric two-dimensional steady flow to non-axisymmetric three-dimensional unsteady flow is considered for various values of the Reynolds number, Re (with Re = ΩR22/v, where v is the kinematic viscosity of air). Axisymmetric calculations are first performed for both aspect ratios in the range 3,858 ≤ Re ≤ 23,150. Fully three-dimensional calculations are then performed for the configuration with Γ = 0.186 and Re = 23,150, and for the configuration with Γ = 0.279 and Re = 7,715, 15,430, and 23,150. The axisymmetric calculations performed with Γ = 0.186 confirm many known features of the flow, including the transition from a steady flow to an oscillatory periodic regime. This occurs at about Re = 23,150 for a configuration with a/H = 0, and at about Re = 14,670 for one with a/H = 0.28 and a finite disk thickness (b/H = 0.2). Three-dimensional calculations performed for Γ = 0.186 with a/H = 0 and Re = 23,150 reveal a circumferentially periodic flow pattern with eight foci of intensified axial component of vorticity. The axisymmetric calculations performed with Γ = 0.279 yield a novel, non-unique steady solution for the velocity field that is asymmetric with respect to the interdisk midplane. No experimental verification of this finding exists to date, but similar situations are known to arise in the context of anomalous modes of the Taylor-Couette flow. Relaxing the axisymmetry constraint allows this flow to evolve to an oscillatory three-dimensional regime of increasing irregularity with increasing rotational speed. In this case, the number of foci of intensified axial vorticity varies with time, ranging from six at Re = 7,715 to between six and eight at Re = 23,150.
A Computational-Experimental Development of Vortex Generator Use for a Transitioning S-Diffuser
Authors: Wendt Bruce J. , Dudek Julianne C. 
Published: July 2023

Abstract
The development of an effective design strategy for surface-mounted vortex generator arrays in a subsonic diffuser is described in this report This strategy uses the strengths of both computational and experimental analyses to determine beneficial vortex generator locations and sizes. A parabolized Navier-Stokes solver, RNS3D, was used to establish proper placement of the vortex generators for reduction in circumferential total pressure distortion. Experimental measurements were used to determine proper vortex generator sizing to minimize total pressure recovery losses associated with vortex generator device drag. The best result achieved a 59% reduction in the distortion index DC60, with a 0.3% reduction in total pressure recovery.
Determination of Temperatures and Heat Fluxes on Surfaces of Multi-Domain Three-Dimensional Electronic Components
Authors: Martin Thomas J. , Dulikravich George S. 
Published: July 2023

Abstract
A new algorithm that uses the boundary element method (BEM) has been developed for determining steady thermal boundary conditions on surfaces of three-dimensional solids where such quantities are unknown. Given temperature and heat flux on surfaces where such data is readily available, the algorithm computes, non-iteratively, the temperature field within the entire object and any unknown thermal boundary conditions on the surfaces where thermal boundary values are unavailable. An inverse BEM computer program has been developed and was successfully tested on several simple geometries where the analytic solutions of the well-posed problem were known. Our non-iterative algorithm for inverse determination of unknown thermal boundary conditions is very fast and highly flexible in treating complex three-dimensional geometries including interior cavities, mixed thermal boundary conditions and multiple domains with different thermal properties. Besides surface input data, this algorithm accepts also temperatures and heat fluxes at isolated interior points as input data.
High Resolution Thermal Design Tools for Air-Cooled Electronics Components and Systems
Authors: Przekwas Andrzej J. , Athavale Mahesh M. , Ho Yin-H. 
Published: July 2023

Abstract
The packaging trends for the latter part of the 1990’s appear to suggest that advanced computing and military application multi-chip modules (MCMs) will generate tremendous heat loads. Advanced, accurate design tools will be needed to evaluate new cooling concepts entailing complex geometries and complex physics, and which are capable of solving large scale numerical problems. This paper presents a high resolution computational model for thermal design of high density electronic packages. Details of numerical model for strongly implicit conjugate heat transfer are discussed. A novel high accuracy numerical wall scheme has been presented to resolve near wall shear stresses and wall heat fluxes. Three electronics cooling problems have been selected to validate the computer code on complex geometry configurations. These configurations are: an SMT module with fully resolved leadframe, 256 pin heat sink and a 20 module MCM with 74 fin heat sink. Results of the computational study are compared with available experimental data. In all three cases very good agreement with experiment has been achieved.
Optimization of Solder Joint Fatigue Life Using Product Model-Based Analysis Models
Authors: Cimtalay Selçuk , Peak Russell S. , Fulton Robert E. 
Published: July 2023

Abstract
Product Model-Based Analysis Models (PBAMs) have been presented as highly automated analysis modules for designer usage. Previous examples such as solder joint fatigue PBAMs have shown how explicit design-analysis associativity linkages enable seamless interfaces to solution tools (e.g., finite element analysis systems). These examples focused on using PBAMs for design verification, where a criteria such as fatigue life was checked given one design state as an input.
This paper presents a technique which utilizes PBAMs for design optimization. An example is given which maximizes solder joint fatigue life by iteratively changing PBAM inputs (the design variables) based on PBAM outputs (the analysis results). Benefits of the technique include the modular and flexible addition of an optimization agent to existing analysis modules.
Design of Automotive Body Structure for Roof Crush
Authors: Mahmood H. F. , Baccouche M. R. 
Published: July 2023

Abstract
This paper investigates the parameters that influence the design and analysis of automotive structures subject to roof crush loading. Influence of components such as roof bows, A-pillars, B-pillars, roof side rails, windshield header, and windshield glass on the load carrying capacity of the green house structure is discussed. Several analysis of the roof model were carried out to simulate the effect of roof bows, windshield glass, windshield header, and roof side rail span. The results of this analysis are discussed in terms of components contribution to the strength and stability of the greenhouse structure. The mode of collapse of the 3D roof structure is analyzed and the formulation of the plastic hinges and maximum collapse moment is discussed.
Results from a non-linear finite beam element system code are presented in this paper. Axial and bending strengths, sequences of failure, and modes of collapse from this code are discussed at both the component and system level. Also presented in this paper is a summary of engineering guidelines and recommendations for designing roof structure components to carry roof crush load.
Crush Behavior of Spot Welded Hat Section Components With Material Comparison
Authors: Omar Tarek A. , Kan Cing-Dao , Bedewi Nabih E. 
Published: July 2023

Abstract
The computer aided design of vehicle steel alloy structures is well understood and fairly reliable. Finite element (FE) models for crash analysis, in both frontal and side impact, can be developed with high degrees of fidelity, and are playing a major role in automotive design today. The substitution of aluminum alloys in the load bearing components has added a level of complexity in the FE modeling. Issues related to validation of material constitutive models, failure modes, fracture and general material modeling have to be addressed in these new materials.
This paper describes the results of a study conducted to investigate and compare the crush performance of mild steel and aluminum alloy in main frontal load bearing vehicle components. Finite element models of spot-welded hat section stub columns were created and numerically simulated using the non-linear dynamic code LS-DYNA3D. Recommendations are provided for both FE models and simulation parameters in order to obtain an accurate and fair representation of the real test. Much of the analysis is obtained on optimization of results with respect to computation time. The crush behavior of hat section stub columns was studied under quasi-static and dynamic loading rates and then validated against published experimental results. Two different steel alloys and two different aluminum alloys have been used in the analysis. The strain rate effect has been considered for the steel alloys under two crushing rates of 8 m/s and 12 m/s. The mathematical modeling of resistance spot-welding joints in aluminum was also considered. Parameters as energy absorption, peak crush load capacity, and the crush distance are used to compare the crush behavior of steel and aluminum alloys in the main load bearing components.
Analytical Studies of Airbag System Design for Side Impacts
Authors: Wang J. T. , Deng Y.-C. , Ressler G. E. 
Published: July 2023

Abstract
In this paper, we present an analytical study of design optimization of side airbag systems with respect to three chosen driver-side-like prototype inflators. An airbag/SID model has been developed in CAL3D. This model was used with a CAL3D design optimization program to identify airbag designs that met all FMVSS 214 requirements, assuming the feasibility of developing such a system in hardware. The results of this study were then used to guide the experimental work of side airbag system development.
A Numerical Correlation for the Solidification of Liquid Metal Droplets Impacting Onto a Substrate
Authors: Tong Albert Y. , Holt Brendon R. 
Published: July 2023

Abstract
The problem of normal incidence impact with solidification of a spherical liquid metal droplet onto a rigid planar substrate is studied. The Navier-Stokes equations are solved using a finite-volume formulation with a fixed grid. The free surface of the droplet is tracked by the Volume of Fluid (VOF) method. The surface tension on the droplet surface is evaluated by a Continuum Surface Force (CSF) model. The energy equation which includes both convection-diffusion heat transfer and a mushy-region for the phase change (solidification) is modeled by using an enthalpy-based formulation. The method developed provides a comprehensive model of the dynamic and thermal aspects of the impact process. A parametric study has been performed. The effects of several parameters on the spread of the droplet on the substrate are determined. The information is used to develop, via dimensional analysis, a relationship between non-dimensional numbers and the spread factor. A correlation that predicts the spread factor as a function of some non-dimensional numbers is obtained which can serve as a design tool for liquid metal jetting applications. The correlation agrees with the experimental data available in the literature suggesting that the basic impact mechanics have been captured in the numerical model.
A Technique for Measuring Volume and True Density of the Solid Matrix of Cartilaginous Tissues
Authors: Gu W. , Lewis B. , Lai W. M. , Ratcliffe A. , Mow V. C. 
Published: July 2023

Abstract
Cartilage and intervertebral disc (IVD) are examples of charged hydrated soft tissues consisting of three phases: a water phase, a solid phase (e.g., the collagen-proteoglycan matrix) and an ion phase (e.g., NaCl). It has been known for many years that the mechanical and swelling behaviors of these tissues are affected by their water content. For example, both theoretically and experimentally, we know that the hydraulic permeability and the aggregate modulus are related to the tissue porosity, density, and fixed charge density [1–6]. These intrinsic tissue properties will also influence other mechanical behaviors of the tissue, such as creep and stress-relaxation. To quantify these types of functional dependence, a triphasic constitutive law was developed to describe the mechanical and physicochemical behaviors of charged-hydrated soft tissues [6]. In this theory, it was postulated that the Helmholtz free energy functions depend on the apparent densities of the constituents which are related to the porosity of the tissue and true density of the constituents. However, the true porosity (water volume per unit volume of tissue) and the true density of the solid matrix (solid mass per unit volume of solid) have never been measured Thus the objective of this investigation is to develop an accurate method to measure the volumes of such tissues and of its solid matrix. From these measured volumes the true porosity and true density of the solid matrix can be calculated.
Finite Element Analysis of the Role of Dynamic Perfusion and Optical Properties in Laser Coagulation of Biological Tissue
Authors: Kim Beop-Min , Rastegar Sohi , Jacques Steven L. , Thomsen Sharon , Motamedi Massoud 
Published: July 2023

Abstract
Laser coagulation of highly vascular biological tissue such as prostate or liver includes coupled optical and thermal processes [1]-[2] which may not be accurately modeled if temperature dependence of tissue properties are not taken into consideration. The objective of this study is to investigate the effect of dynamically varying blood perfusion rate and tissue optical properties during heating on the final depth of lethal thermal damage using a nonlinear finite element method (NFEM).
Transient Impact Response of the Body During a Fall on the Outstretched Hand
Authors: Chiu James , Robinovitch Stephen N. 
Published: July 2023

Abstract
The distal radius is the most commonly fractured bone in the human body. Over 90% of such fractures are caused by falls onto the outstretched hand [1]. However, few biomechanics studies have explored the risk for distal radius fracture associated with a fall onto the upper extremity, or the reduction in fracture risk provided by wrist guards or energy absorbing floors.
Mechanical Strain Environment Controls New Bone Formation During Distraction Osteogenesis
Authors: Richards Mark , Weiss Jeffrey A. , Alsberg Eben , Shibuya Takaaki , Schaffler Mitchell B. , Goldstein Steven A. , Goulet James A. 
Published: July 2023

Abstract
An animal model of distraction osteogenesis was used to investigate the effects of altered stresses and strains on tissue development, differentiation, and repair. Osteotomies were performed at 0 and 45 degrees to create different mechanical environments within the distraction gap. Finite element simulations of functional loading and actual distractions indicated significant changes in the gap deformation field. These differences correlated with significant decreases in new bone volume and changes in trabecular architecture for the 45-degree case.
Control of Mixing With Micro Injectors for Combustion Application
Authors: Tseng Fan-Gang , Linder Christian , Kim Chang-Jin , Ho Chih-Ming 
Published: July 2023

Abstract
In this paper, we propose to use micro injectors to control mixing of flow for combustion enhancement. The principle and development of the micro injectors are described. Ejection of droplets (8 μm in diameter) from the micro injectors has been detected with a pulse train of 53 mA current, 1 kHz frequency, and 1/30 duty cycle. In parallel, an air jet experiment has been performed to control the shedding frequency of the air jet with perpendicularly injected droplets by utilizing a commercial inkjet printhead (HP 51604A) as the source of droplets. The results demonstrated the ability for the injected droplets to change the flow’s characteristic frequency from the natural shedding one to the forcing (injection) one.
Monatomic and Polyatomic Gas Flow Through Uniform Microchannels
Authors: Shih Jack C. , Ho Chih-Ming , Liu Jianqiang , Tai Yu-Chong 
Published: July 2023

Abstract
The phenomenon of flow through a small channel with dimensions of 4000μm × 40μm × 1.2μm is examined. The microchannel is manufactured by incorporating procedures originally designed to fabricated integrated circuit chips. Chip packaging is done to connect the micropressure transducers on the chip to a data acquisition system for pressure distribution measurements. Mass flow rate on the order of 10−12kg/s is measured using an accumulation scheme. Helium and nitrogen gases are used in the study. Flow is modeled using the Navier-Stokes equation together with the slip boundary condition.
Micro Manipulation Based on Micro Physics: Micro Pyramids on Endeffector Surface for Attractive Force Reduction
Authors: Arai Fumihito , Andou Daisuke , Nonoda Yukio , Fukuda Toshio 
Published: July 2023

Abstract
Micro manipulation is required for assembling and maintenance of micro machines and their parts. As the handling objects are miniaturized, attractive forces such as van der Waals force, surface tension force and electrostatic force between micro objects and gripper surface become dominant in the air, and they work as adhesive forces. We cannot neglect such adhesive forces in micro manipulation. We should consider the physical phenomena in the micro world for micro manipulation. So, we propose reduction methods of adhesive forces. Surface roughness of the endeffector surface is effective to reduce the van der Waals force. We propose to make the micro pyramids on endeffector surface by the micromachining techniques. We designed and made a prototype of the micro gripper with the endeffector whose surface is covered with the micro pyramids. Micro pyramids were effective for van der Waals force reduction.
Fabrication of Surface-Micromachined Polysilicon Microactuators Using HF Gas-Phase Etching Process
Authors: Lee Jong Hyun , Park Kyung Ho , Lee Chun Su , Baek Jong Tae , Kim Chang-Jin , Yoo Hyung Joun 
Published: July 2023

Abstract
The newly developed HF GPE (gas-phase etching) process is introduced as an effective release method for polysilicon surface micromachining. With no liquid involved during any of the steps for releasing, unlike other reported release techniques, the HF GPE process produces polysilicon microstructures with virtually no process-induced stiction problem. We demonstrate the effectiveness of this new technique by fabricating various polysilicon structures including electrostatic comb drivers. They consist of doped polysilicon as the structural thin film and TEOS (tetraethylorthosilicate) as the sacrificial layer. The troublesome moisture effect, persisting in earlier attempts, is solved by using anhydrous HF gas and CH3OH vapor. The HF GPE process is further tuned for high etch rate, as high as 10 μm/hr, which is comparable to the wet etching. Measurement of the residual-stress gradient through the thickness of the polysilicon layer is also reported.
An Approach to Macromodeling of MEMS for Nonlinear Dynamic Simulation
Authors: Ananthasuresh G. K. , Gupta Raj K. , Senturia Stephen D. 
Published: July 2023

Abstract
The method of linear normal mode summation is utilized here to construct reduced order macromodels to perform the nonlinear dynamic analysis of microelectromechanical devices and systems (MEMS). The validity of the approach is illustrated with the example of a doubly clamped beam under electrostatic actuation. Using the reduced order macromodel, it is possible to observe nonlinear effects such as the frequency shift due to a DC bias voltage, and the amplitude-dependence of resonance frequency. The undamped dynamic pull-in voltage is found to be about 9% less than the quasi-static pull-in voltage. The dynamic simulation results of the macromodel are compared with those of the complete model, and it is noted here that linear normal modes provide an adequate basis to carry out the dynamic analysis with enormous computational advantage while not losing accuracy. The simulation results are also validated with the experimentally measured data for the dynamic and static pull-in voltages, and the time to pull in at voltages beyond the pull-in voltage.