bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficiency of Frequency-Rectified Piezohydraulic and Piezopneumatic Actuation
Authors: Nasser Khalil , Leo Donald J. 
Published: November 2021

Abstract
Piezohydraulic and piezopneumatic frequency rectification is analyzed with a steady-state model of work and energy transfer. In this paper, piezohydraulic actuation is defined as the use of incompressible fluid to rectify the oscillatory motion of a piezoelectric device into unidirectional motion; piezopneumatic actuation is the use of a compressible gas such as air. The steady-state analysis is based on the definition of two efficiency metrics. The mechanical efficiency is defined as the ratio of mechanical work transfered to the load to the total mechanical work performed by the actuator, and the electrical efficiency is defined as the ratio of electrical energy expended to the peak energy required. The analysis demonstrates that piezohydraulic rectification is inherently more efficient than piezopneumatic rectification due to the assumption of fluid incompressibility. The mechanical effieciency is 100% when using incompressible fluid (ideal) but drops to below 40% when using compressible gas. The maximum electrical efficiency of piezohydraulic rectification is also four times higher than that of piezopneumatic actuation (29% to 7%). The overall efficiency of the rectification process (defined as the product of the mechanical and electrical efficiencies) is an order of magnitude greater when using incompressible fluid than when using compressible gas (29% to 2.8%). Thus, frequency rectification using compressible gas will require peak energy inputs that are ten times greater than that of incompressible fluid for an equivalent amount of mechanical work output. The significant difference in peak energy requirements is attributed to the reduced coupling between the actuator and the load that occurs due to compressibility of the gas. These results represent an upper bound on the efficiency because they neglect other sources of system losses, such as material hysteresis and frictional losses within the piston and seals of the actuator.
Modeling and Control of Pantograph and Contact Wire for High Speed Train
Authors: Muenchhof Marco , Hindle Timothy , Singh Tarunraj 
Published: November 2021

Abstract
The paper focuses on the modeling and control of a catenary-pantograph system. For the catenary system, only the contact wire is considered. Initially, the case of a constant force traveling at a constant velocity along the wire is investigated and closed form solutions are derived. Next, the pantograph dynamics are considered using a simple spring-mass-damper model, where the force is no longer assumed to be constant. The need for control in this case is apparent and motivates two different control strategies. The first control strategy utilizes a feed-forward Fourier series control profile. For the second control strategy, a proportional force feed-back control is added. All control parameters are obtained using constrained optimization techniques. Stability and sensitivity issues are addressed.
Process-Oriented Tolerance Synthesis for Multistage Manufacturing Systems
Authors: Ding Yu , Jin Jionghua , Ceglarek Dariusz , Shi Jianjun 
Published: November 2021

Abstract
In multistage manufacturing systems, quality of final products is strongly affected not only by product design characteristics but also by key process design characteristics. However, historically, tolerance research has primarily focused on allocating tolerances based on product design characteristics for each component. Currently, there is no analytical approach for multistage manufacturing processes to optimally allocate tolerances to integrate product and process characteristics at minimum cost. One of the major obstacles is that the relationship between tolerances of process and product characteristics is not well understood and modeled. Under this motivation, this paper aims at presenting a framework addressing the process-oriented (rather than product-oriented) tolerancing technique for multistage manufacturing processes. Based on a developed state space model, tolerances of process design characteristics at each fabrication stage are related to the quality of final product. All key elements in the framework are described and then derived for a multistage assembly process. An industrial case study is used to illustrate the proposed approach.
Effect of Mechanical Alignment System on Assembly Accuracy
Authors: Lee Neville K. S. , Yu Grace H. , Zou Y. , Chen J. Y. , Joneja Ajay 
Published: November 2021

Abstract
Mechanical means of positioning are frequently used in mechanical assembly processes. However, very little attention has been paid to the selection of mechanical alignment systems (MAS) for assembly processes. Our analysis shows that if the MAS are not properly selected, the form errors as well surface waviness and roughness of the workpieces to be assembled can badly limit the level of accuracy achievable. A simulation-based methodology is described to study the alignment accuracy for multi-stage processes. Such cases are common, where fabrication operations are done on parts before they are assembled. The study shows that if the workpieces are aligned in the same orientation, using similar or identical MAS for the fabrication processes and assembly processes, then the effect of the form errors as well as surface waviness and roughness of the workpieces can be greatly suppressed.
Stream of Variation Modeling and Diagnosis of Multi-Station Machining Processes
Authors: Huang Qiang , Zhou Nairong , Shi Jianjun 
Published: November 2021

Abstract
Product dimensional quality is one of the most important topics in machining processes. However, limited research has been done on the dimensional control and root cause identification methodologies in multi-station machining processes. This paper will study the stream of variation (SOV) problem by developing a new type of model — State Space Model — to describe the dimensional deviation of the multistation machining processes. A process level diagnostic methodology is also developed. A case study is presented to illustrate the developed modeling and diagnostics methodology.
Feature Selection for Tool Wear Diagnosis Using Soft Computing Techniques
Authors: Goebel Kai , Yan Weizhong 
Published: November 2021

Abstract
This paper examines feature selection methods in the context of milling machine tool wear diagnosis. Given raw sensor signals acquired during experiments, a pool of features was created through calculation by several feature extraction methods. Five techniques for selecting the most discriminating features were employed. These techniques included decision trees, neural-fuzzy methods, scatter matrix, and a cross-correlation method. We used a diagnostic neural network to evaluate the five different feature selection schemes by comparing their classification rate and test errors.
Effects of Thermal Expansion on Surface Error in Metal Cutting
Authors: Wu Chung_sheng , Kuo Chuan-Hsien , Yang Wen-Jei 
Published: November 2021

Abstract
An experimental study is performed to measure thermal expansion and surface roughness of 6061 aluminum workpiece subjected to a cutting process in turning on a lathe. Four capacitance probes are used to detect changes in the air gap between the probes and the surface of the workpiece during the machining process, and after the workpiece is cooled down to the initial temperature. The signal output from the probes is filtered before being fed into a data acquisition system. Operational conditions are varied. The thermal expansion-time history of the workpiece is obtained at different locations behind the cutting point, together with the filtered surface profile of the workpiece. The effects of cutting speed, flank wear length, and workpiece diameter on thermal expansion and average surface roughness are determined. A novel approach is developed to correlate thermal expansion against surface roughness, both in dimensionless form. It is disclosed that these two quantities are linearly related on a semi-logarithmic plot, with all test data falling within upper and lower limits. A quantity analogous to the elastic modulus is defined to characterize the surface roughness of materials resulting from the cutting process in turning. This approach will suggest new directions for the study of surface roughness in machining.
An Improved Cutting Force Model Considering the Size Effect in End Milling
Authors: Yun Won-Soo , Cho Dong-Woo 
Published: November 2021

Abstract
In this paper, a mechanistic model is first constructed to predict three-dimensional cutting forces, and the uncut chip thickness is calculated by following the movements of the position of the center of a cutter, which varies with the nominal feed, cutter deflection and runout. For general implementation to a real machining, this paper presents the method that determines constant cutting force coefficients, irrespective of the cutting conditions or cutter rotation angles. In addition, this study presents the approach which estimates runout-related parameters, the runout offset and its location angle, using only one measurement of cutting forces.
For more accurate cutting force predictions, the size effect has to be considered in the cutting force model. In this paper, two approximate methods are suggested since the strict approach is practically impossible due to a measurement problem. The size effect is individually considered for narrow and wide cuts.
A Predictive Model for Helical End Milling Forces
Authors: Li Huaizhong , Zhang Wenbin , Li Xiaoping 
Published: November 2021

Abstract
A predictive model for helical end milling forces is developed using a predictive machining theory, which predicts cutting forces from input data of workpiece material properties, tool geometry and cutting conditions. In the model, each tooth of a helical end milling cutter is discretizised into a number of slices along the cutter axis to account for the helix angle effect on the cutting forces. The cutting action of each of the slices is modeled as an oblique cutting process. For the first slice of each tooth, it is modeled as oblique cutting with end cutting edge effect and tool nose radius effect, whereas the cutting actions of other slices are modeled as oblique cutting without end cutting edge effect and tool nose radius effect. The total cutting forces acting on the cutter is obtained as the sum of the forces at all the cutting slices of all the teeth. Experimental milling tests have been conducted to verify the model which showed good agreements.
Advanced Deposition Techniques for Freeform Fabrication of Metal and Ceramic Parts
Authors: Tseng Ampere A. , Tanaka Masahito 
Published: November 2021

Abstract
Two newly invented deposition techniques for the freeform fabrication of metal and ceramic parts are presented. The first deposition technique studied is one that can deposit variable sizes of filaments in a controlled manner. The second technique consists of layer deposition using an adjustable planar nozzle to generate layers directly. Laboratory scale apparatus has been built to study the behavior of filament and layer formation of these two techniques. Experiments are conducted in typical operation ranges. Analytical solutions are also developed to parametrically study the effects of changing major operational parameters as well as to provide necessary information for designing the apparatus. All results indicate that the analytical predictions agree very well with the experimental observation. Finally, recommendations on the future development of these two techniques are given.
Solid Freeform Fabrication of Metal Parts by 3D Laser Cladding
Authors: Hu Dongming , Kovacevic Radovan , Valant Mike 
Published: November 2021

Abstract
This paper presents the development of a method of three-dimensional laser cladding for Solid Freeform Fabrication (SFF). A SFF system developed at SMU (SMU-SFF) is introduced which can build 3D metal parts by cladding metal powder delivered by a nozzle mounted coaxially to a Nd: YAG laser focusing head. An on-line slicing process that uses machine vision to measure the height of the part being built is also introduced as an effective means of optimizing the cladding process. Further, to explore the effects of the laser cladding parameters on the SFF results, machine vision with a high-speed shutter camera is utilized to observe the laser cladding process. The relationships between processing parameters (laser power, scan velocity) and cladding results are then discussed.
Ultrasonic Rapid Manufacturing of Layered Objects
Authors: Doumanidis Charalabos , Gao Yuan , Johnson Norbert , Greif Robert 
Published: November 2021

Abstract
The Ultrasonic Rapid Manufacturing process is a new non-thermal rapid prototyping technique for layered fabrication of metallic or multiple-material products. The process introduced in this paper employs ultrasonic welding and contour cutting of thin material foils. Its laboratory implementation, automation and integration, and parameter optimization are described first. Next, a numerical FEA simulation of the static and dynamic stress/strain field, based on experimental calibration of the friction coefficient between the welded surfaces, is established and found in agreement with laboratory strain data. Last, the technical advantages of the process, including fabrication of dense, full-strength functional solid metal parts, multiple-material composites, and active parts with embedded intelligent components and electronic, mechatronic, optic and fluidic structures, are examined in the manufacturing industry.
Design and Analysis of Piezoelectric Actuators Produced by Solid Freeform Fabrication
Authors: Cheeseman Bryan A. , Chen Baoxing , Safari Ahmad , Danforth Stephen C. , Chou Tsu-Wei 
Published: November 2021

Abstract
Solid Freeform Fabrication (SFF) techniques permit the ready manufacture of ceramic actuators possessing unusual and complex shapes. These actuator designs allow for the optimization of material orientation, poling direction and applied potential direction, which can result in increased displacement. Examples of such designs are detailed in this paper and include a dome shaped actuator possessing tangentially alternating poling and a spiral shaped actuator.
A Gradient Based Optimization Framework for the Design of Single and Multi-Stage Metal Forming Processes
Authors: Srikanth Akkaram , Zabaras Nicholas 
Published: November 2021

Abstract
A gradient based optimization methodology is developed for the design of metal forming processes. A novel, efficient and mathematically rigorous scheme is proposed for a continuum based sensitivity analysis of metal forming processes that can be used to accurately evaluate gradients of the objective function and design constraints. In particular, a sensitivity analysis is being developed for the Lagrangian analysis of finite inelastic deformations of hyperelastic-viscoplastic materials involving frictional contact. A framework for shape as well as parameter optimization for single-stage metal forming processes was introduced in [1–4]. Weak sensitivity equilibrium equations were derived for the large deformation of the workpiece in a typical forming operation. This sensitivity kinematic problem was linearly coupled with the appropriate sensitivity constitutive and contact sub-problems. Thus a linear sensitivity problem with appropriate driving forces was identified and the analysis carried out in an infinite dimensional framework. This work on the design of single-stage forming processes is currently expanded to include the design of multi-stage forming processes which necessarily involve the computation of both shape as well as non-shape (parameter) sensitivities. The direct deformation and sensitivity deformation problems are implemented using the finite element method. The effectiveness of the proposed methodology is tested here with the solution of two practical design problems in single and two-stage forming processing.
A Study on Fundamental Mechanisms of Warp and Recoil in Hemming
Authors: Zhang Ellen , Wu Xin , Hu S. Jack 
Published: November 2021

Abstract
In this paper, the occurrence of recoil and surface warp during flat surface-straight edge hemming process is investigated. A general-purpose finite element code ABAQUS/Standard is used to simulate the hemming operations. Reverse bending, localized buckling and springback are the fundamental mechanisms that cause surface warp and recoil. Recoil and warp are not independent. One parameter called final equivalent residual warp is obtained to represent both. Feasible pre-hem ending zone is proposed based on final equivalent residual warp. The influence of the geometrical and process parameters on recoil and warp are also investigated.
Non-Linear Kinematic Hardening Identification for Anisotropic Sheet-Metals With Bending-Unbending Tests
Authors: Brunet M. , Morestin F. , Godereaux S. 
Published: November 2021

Abstract
An inverse identification technique is proposed based on bending-unbending experiments on anisotropic sheet-metal strips. The initial anisotropy theory of plasticity is extended to include the concept of combined isotropic and non-linear kinematic hardening. This theory is adopted to characterise the anisotropic hardening due to loading-unloading which occurs in sheet-metals forming processes. To this end, a specific bending-unbending apparatus has been built to provide experimental moment-curvature curves. The constant bending moment applied over the length of the specimen allows to determined numerically the strain-stress behaviour but without Finite Element Analysis Four constitutive parameters have to be identified by an inverse approach. Our identification results show that bending-unbending tests are suitable to model quite accurately the constitutive behaviour of sheet metals under complex loading paths.
Methodology to Expedite Mechanical Component Design and Analysis in Gas Turbine Engines
Authors: Nguyen Ly D. , Ku Taison 
Published: November 2021

Abstract
Advances in computer technology have enabled the utilization of sophisticated computer software to assist in mechanical design and analysis in various fields. CAD/CAM/CAE software, such as CATIA, UG (Unigraphic), CV (Computervision), ANSYS, NASTRAN, ABAQUS, Hypermesh and Tgrid, have proven to be effective tools for aiding designers and analysts. The challenges offered by these software improvements, are an efficient engineering design and analysis process, and the need for broader training of the designers and analysts conducting these processes. In the past these processes were often done sequentially and proved to be very time consuming.
At Honeywell International Inc., a methodology has been established to synchronize CATIA®, CAD-fix®, ANSYS®, Hypermesh® and Tgrid® in the design and analysis of gas turbine engine components to speed the design analysis process. This paper describes the techniques used on such complex parts as the combustor case, the front frame support and the turbine nozzle to reduce cycle time in the design and analysis process. Modeling process techniques described in this paper include the implementation of cyclic symmetric boundary conditions, data transfer between CATIA and ANSYS using CAD-fix, and mesh control and sizing through the used of Hypermesh and Tgrid.
A High-Order Solution for the Added Stability Lobes in Intermittent Machining
Authors: Corpus William T. , Endres William J. 
Published: November 2021

Abstract
An earlier work by the authors presented a solution for the added ultrahigh-speed stability lobe that has been shown to exist for intermittent and other periodically time varying machining processes. That earlier first-order solution was not clearly extendible to a higher order. A more general analytical technique presented here does permit higher-order results. The solution is developed first for the case of zero damping for which a final closed-form symbolic result can be realized up to second order. More important than improved accuracy, the higher-order nature of the result confirms that there exist multiple added lobes and permits a mathematical description of their locations along the spindle-speed axis. A solution is then derived for the structurally damped case, where the first-order case permits a final closed-form symbolic result while the second-order case requires computational evaluation. The first-order result matches perfectly the previously published one, as expected. The second-order result improves accuracy, measured relative to numerical simulation results, and, more important, permits a second added lobe to be predicted. The second added lobe tends to cut into the region of the high-speed stability peak that is predicted under traditional zero-frequency (time-averaged) analyses. The damped solutions also indicate that structural damping of the dominant mode becomes virtually unimportant at ultrahigh speeds.
Biomechanical Models of the Developing Cardiovascular System
Authors: Taber Larry A. 
Published: November 2021

Abstract
It long has been known that mechanical forces influence the development of the cardiovascular system, but how these forces interact with genes to shape the heart and blood vessels is poorly understood. Recently, biomechanical models have been used to aid researchers studying the developmental processes of growth, remodeling, and morphogenesis. This paper reviews the biology and models for each of these processes.
ER Effect in Liquid Crystal
Authors: Tsukiji Tetsuhiro , Tanabe Shinsuke 
Published: November 2021

Abstract
Liquid crystal is one of homogeneous ER (Electro-rheological) fluids in some range of temperature. In the present study the effect of electric fields on shear stress in liquid crystal is investigated using rotational viscometer. The shear stresses are measured by changing a shear rate, amplitude and frequency of electric fields. Dependence of the shear stress on electrical excitation frequency is mainly investigated. Furthermore flow visualization is conducted and relation between flow rate and pressure drop is measured when liquid crystal flows between two parallel-plate electrodes under application of electric fields. The experimental results are compared with previous ones for ER suspensions.
Dynamic Compressive Failure of Unidirectional E-Glass/Vinylester Composites
Authors: Oguni Kenji , Ravichandran Guruswami 
Published: November 2021

Abstract
Results for unidirectional fiber reinforced polymer composites (E-glass/vinylester) with 30%, 50% fiber volume fractions under dynamic uniaxial compression are presented. Specimens are loaded in the fiber direction using a servo-hydraulic material testing system for low strain rates and a Kolsky (split Hopkinson) pressure bar for high strain rates, up to 3000/s. The results indicate that the compressive strength of the composite increases with increasing strain rate. Post-test scanning electron microscopy is used to identify the failure modes. In uniaxial compression the specimens are split axially (followed by fiber kink band formation). Based on the experimental results and observations, an energy-based analytic model for studying axial splitting phenomenon in unidirectional fiber reinforced composites is extended to predict the compressive strength of these composites under dynamic uniaxial loading condition.
Robust Control of Electrohydraulically Actuated Friction Damper
Authors: Guglielmino Emanuele , Edge Kevin A. 
Published: November 2021

Abstract
This paper focusses on the Sliding Mode Control (SMC) of a servo-driven dry-friction damper employed in a force control loop for the purpose of vibration reduction. An application to a car suspension is investigated using a quarter car model.
The friction damper is a semi-active device: it can only oppose to the motion but not assist it. This inherent limitation requires particular attention in the design of the sliding surfaces. The performance of various types of sliding surface are compared, by means of computer simulation.