bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of Trabecular Bone Yield Using Nonlinear Finite Element Analysis
Authors: Niebur Glen L. , Hsia Andy C. , Chen Tony J. , Keaveny Tony M.
Published: December 2021

Knowledge of the failure properties of trabecular bone will lead to improved modeling of whole bone fracture and bone-prosthesis systems. Because trabecular bone is anisotropic, its yield properties are dependent on orientation. Defining a complete orthotropic yield criterion requires multiple material constants to be determined experimentally. As these constants can depend on both architecture and density, a large numbers of specimens would be needed to develop a complete criterion. This may not be feasible, especially for human bone, due to difficulties in obtaining suitable specimens.
The Effect of Loading Rate on the Load Sharing Between Passive and Active Subsystems of Spine: A Finite Element Analysis
Authors: Wang J. L. , Shirazi-Adl A. , Parnianpour M. , Engin A. E.
Published: December 2021

The effects of dynamic loading rate on the load sharing of passive and active subsytems of the spine were evaluated using a validated viscoelastic finite element (FE) model of a L2-L3 motion segment. Both the force controlled and hybrid force-rotation controlled simulations were performed to best simulate the in-vivo loading conditions. The stiffening response of motion segement at higher loading rate was predicted by both simulation strategies, while the interpretation of the hybrid simulations was much easier due to decoupling of the confounding interactions of load, posture and loading rate. The results collectively indicate that the loading rate markedly effects the distribution of stress/strain in the tissues and reduces the margin of safety of the spine. The results should be used in developing a better biomechanical basis for considering the role of trunk speed as a risk factor for low back disorders.
Biphasic Poroviscoelastic Model Simultaneously Predicts Axial Reaction Force and Lateral Displacement of Articular Cartilage During an Unconfined Compression-Stress Relaxation Experiment
Authors: DiSilvestro Mark R. , Zhu Qiliang , Wong Marcy , Jurvelin Jukka , Suh Jun-Kyo
Published: December 2021

Articular cartilage lining the articulating surfaces in diarthrodial joints is composed of an extracellular matrix and interstitial fluid. The complex mechanical behavior of this tissue has been successfully modeled by the linear biphasic poroviscoelastic (BPVE) model first introduced by Mak (1986). This model, a simple extension of the well-known biphasic theory first proposed by Mow et al. (1980), accounts for both fluid flow-dependent and fluid flow-independent viscoelastic mechanisms which contribute to the overall mechanical behavior exhibited by the tissue. Despite the success of the linear BPVE model for indentation (Suh and Bai, 1997), as well as that described for unconfined compression (Suh and DiSilvestro, 1997, 1998), the model’s ability to account for more than one measurable variable with a single parameter set has not been established. Therefore, the objective, of this study was to assess the ability of the linear BPVE model to account for both the axial reaction force and lateral deformation of a cylindrical plug of articular cartilage subjected to unconfined compression under a stress relaxation protocol.
Material Constants for Human Annulus Fibrosus Depend on Water Content and Reference Configuration
Authors: Klisch Stephen M. , Lotz Jeffrey C.
Published: December 2021

We apply a special theory of an incompressible mixture of an elastic solid and an inviscid fluid (Klisch and Lotz, 1998) to experimental data for healthy human annulus fibrosus tested in a stress-relaxation confined compression protocol. The material constants revealed no significant differences due to orientation (i.e., axial vs. radial, n = 16). The aggregate modulus and initial permeability constants were significantly different (n = 32) due to the choice of theory used to fit the data (i.e., that of Klisch and Lotz (1998) vs. that of Holmes and Mow (1990)) and were significantly correlated with initial water content.
The Effect of Trunk Velocity on Concentric and Eccentric Isokinetic Extension Strength of Healthy Men
Authors: Ng Joseph K.-F. , Chan William , Chung Keny , Hung Dino , Lun C. L. , Tang William , Parnianpour Mohamad
Published: December 2021

The dynamic contractile behavior of the muscle is commonly represented by the torque-velocity relation, which is an inverse hyperbolic relationship between muscular tension and the velocity of muscle action (shortening in concentric, static in isometric and lengthening in eccentric muscle actions). This relationship has been well established for extremity muscles but this study extended the range of trunk velocity (−60 to 60 °/sec) that had been used for trunk extensors in the past. The effect of velocity was significant on trunk extensor strength, while the expected plateau was not found within the speed considered.
Seat Failure in Rear Impacts
Authors: Friedman Keith , Gaston Fiona , Bish Jack , Sances Anthony
Published: December 2021

An analysis of rear end accidents involving 1377 driver and right front seat occupants was conducted examining the probability of seat performance failure as a function of crash severity and the injury severity as a function of both crash severity and seat performance. The results suggest that occupants with seat failures experience serious injury more frequently than without such failures for the same Delta-V. Intrusion into the area behind the occupant’s seat appears to be an important consideration in increasing the risk of injury.
Biomechanical Analysis of Padding
Authors: Sances Anthony , Herbst Brian , Forrest Stephen , Meyer Steven E. , Khadilkar Anil V.
Published: December 2021

Padding materials are routinely used to reduce the potential for head injury. The interior of vehicles has been identified as an area where injury can occur in the absence of padding. Head impacts with roof, pillars and support structures have been studied by Fan, Monk, and Friedman. Recent rulemaking by the National Highway Traffic Safety Administration has identified padding as a potential mechanism for reduction in head injury. Helmets utilize padding for energy management so as to reduce the potential for head injury. (Meyers, Becker). The occurrence of diffuse axonal injury with direct impacts and translational accelerations have been evaluated by Nishimoto. Mclean has suggested that brain injury does not occur without head impact.
Design of a Sports Knee Prosthesis
Authors: DiAngelo Denis J. , Evans Charles E.
Published: December 2021

Typical walking prostheses maintain stability during stance with a knee locking mechanism; i.e., a frictional device (mechanical brake) or free rotating knee joint (single pinned or multi-link system) held in a hyper-extended orientation (de Vries, 1995). Attempts to jog with a walking prosthesis are difficult and unsafe. A previous gait study of a “pogo-stick” A/K jogging prosthesis found that the device provided alternating periods of support and non-support between the amputated and non-amputated sides, but required greater energy expenditure from the intact limb and induced larger impact loads (DiAngelo et al., 1989). A computer modeling technique was used to design a multi-link above-knee (A/K) prosthesis that provided continuous, controlled knee flexion during weight bearing and free knee rotation during swing. Aspects of the design were improved energy expenditure, symmetrical gait, and reduced impact loading. Biomechanical data for the computation model was obtained from a gait study of an A/K amputee jogger. The objective of the study was to develop prosthetic knee that provided continuous knee flexion throughout weight bearing and free rotation during swing.
Through-Tool Coolant Drilling of Aluminium/SiC Metal Matrix Composite
Authors: Barnes S. , Pashby I. R.
Published: December 2021

Through-tool coolant has been applied to the drilling of a 2618 aluminium alloy reinforced with 18% silicon carbide (SiC) particles. Titanium nitride coated, K10, solid carbide drills were used to investigate the effect of the coolant application method on the performance of the drilling operation. Through holes were drilled in a 24 mm thick workpiece material without the application of any coolant, with the conventional application of coolant and with the coolant applied through-the tool. Cutting forces were measured during the drilling trials in addition to the wear on the drills, the extent of the entry and exit burrs produced on the workpiece and the quality of the holes produced. The results obtained provided strong evidence that the conventional application of coolant was having no beneficial effect on the cutting operation compared to dry drilling. However, there was very little evidence of an increase in drill wear which some workers suggest is associated with the formation of an abrasive slurry when using coolant with MMCs. Nevertheless, examination of the used drills in the scanning electron microscope confirmed abrasion as the primary wear mechanism. The results showed mat even at the low coolant pressures, through-tool cooling gave a significant improvement in tool wear, cutting forces, surface finish and the height of the burrs produced. Consequently, the recommendations from this work are that through-tool coolant can result in a marked improvement in performance when drilling MMCs and that conventional cooling has virtually no effect on the machinability of this material compared with dry drilling.
Nonlinear Modeling of 3D Open-Cell Foams
Authors: Wang Yu , Cuitiño Alberto M.
Published: December 2021

In this article, we present a hyperelastic model for light and compliant open cell foams with an explicit correlation between microstructure and macroscopic behavior. The model describes a large number of three dimensional structures with regular and irregular cells. The theory is based on the formulation of strain-energy function accounting for stretching which is the main deformation mechanism in this type of materials. Within the same framework, however, bending, shear and twisting energies can also be incorporated. The formulation incorporates nonlinear kinematics which traces the evolution of the structure during loading process and its effects on the constitutive behavior, including the cases where configurational transformations are present leading to non-convex strain-energy functions. Also nonlinear material effects at local or beam level are introduced to accommodate a wide range of different material behaviors. Since the micromechanical formulation presented here has explicit correlation with the foam structure, it preserves in the constitutive relation the symmetries or directional properties of the corresponding structures, including the cases of re-entrant foams which exhibit negative Poisson’s ratio effects. The model captures the central features exhibit by these materials. Predictions of the model for macroscopic uniaxial strain are presented in this article.
A New X-Actuator Design for Controlling Wing Bending and Twisting Modes
Authors: Ye R. , Ding J. H. , Tzou H. S.
Published: December 2021

Recent development of smart structures and structronic systems has demonstrated the technology in many engineering applications. Active structural control of aircraft wings or helicopter blades (e.g., shapes, flaps, leading and/or trailing edges) can significantly enhance the aerodynamic efficiency and flight maneuverability of high-performance airplanes and helicopters. This paper in to evaluate the dual bending and torsion vibration control effects of an X-actuator configuration reconfigured from a parallel configuration. Finite element (FE) formation of a new FE using the layerwise constant shear angle theory is reviewed and the derived governing equations are discussed. Bending and torsion control effects of plates are studied using the FE method and also demonstrated via laboratory experiments. FE and experimental results both suggest the X-actuator is effective to both bending and torsion control of plates.
Dynamic Modeling of an Innovative Piezoelectric Actuator for Minimally Invasive Surgery
Authors: Edinger Benjamin , Frecker Mary , Gardner John
Published: December 2021

A small piezoelectric inchworm actuator has been designed for use with a monolithic compliant end-effector in minimally invasive surgery procedures. A dynamic model of the inchworm actuator has been developed using SIMULINK. Utilizing the equations of motion for the inchworm actuator, the dynamic characteristics of the piezoelectric stack material, and the known compliance of the gripper, a force measurement model has been developed which extracts resisting force information from the piezoelectric signal. The focus of this paper is on the development of the dynamic model and the results of a simulation study that will be used to develop optimal driving signals for the inchworm actuator. Simulation results include the predicted displacement capabilities and settling time of the inchworm actuator over a range of driving frequencies.
Development of Piezoelectrically Actuated Elastodynamic Flapping Micro-Aerial Vehicles
Authors: Cox Adam , Monopoli Daniel J. , Goldfarb Michael , Garcia Ephrahim
Published: December 2021

A discussion of the principles involved in small-scale flight is presented here. In addition, several novel mechanisms have been developed in an attempt to mechanically emulate flapping flight on the meso-scale. Wings are being developed which will exploit particular material properties to emulate the dynamic characteristics of insect wings. The flapping mechanisms developed in this paper use piezoelectric unimorph actuators integrated with compliant, solid-state flexure based mechanisms. Four and five bar linkages are used to convert the linear unimorph output into a single degree-of-freedom rotational flapping motion. Due to their capacitive nature, piezoelectric actuators generally dissipate less power than traditional actuation methods such as electromagnetic motors. Piezoelectric actuators possess a high power density and are capable of high force output. They are frequently used to induce structural resonances, making them suitable for use in these devices. The dynamics of these systems rely on the mechanics of flexure mechanisms, the mechanical and electrical behavior of the piezoelectric elements, and the aerodynamic interaction of the wings and the air, resulting in a complex, nonlinear problem.
Active Vibration Control of a Space Truss Using PZT Stack Actuator
Authors: Song Gangbing , Vlattas John , Johnson Scott E. , Agrawal Brij N.
Published: December 2021

This paper presents design, implementation and experimental results of active vibration control of Naval Postgraduate School (NPS) Space Truss using a piezoelectric ceramic stack actuator. The NPS space truss represents a flexible spacecraft structure which may support interferometer, antenna, and other vibration-sensitive instrumentation. To simulate the effects of a spacecraft disturbance on the truss, a proof mass actuator is incorporated on the structure to excite the truss. To reduce the vibrations caused by the proof mass actuator, an active strut member is installed along a diagonal of the base bay of the truss. The active strut element consists of a piezoelectric ceramic actuator stack, a force transducer, and mechanical interfaces. An integral plus double-integral force controller is designed to suppress vibration of the truss. Experimental results demonstrate that the active piezoceramic strut actuator can effective reduce truss vibration.
A New Technology for Three-Dimensional Cell Culture: The Hydrodynamic Focusing Bioreactor
Authors: Tsao Yow-Min D. , Gonda Steve R.
Published: December 2021

The Hydrodynamic Focusing Bioreactor (HDFB) developed by NASA at the Johnson Space Center provides a unique hydrofocusing capability that simultaneously enables a low-shear culture environment and a unique hydrofocusing-based “herding” of suspended cells, cell aggregates, and air bubbles. The HDFB is a rotating dome-shaped cell culture vessel with a centrally located sampling port and an internal rotating viscous spinner attached to a rotating base. The vessel and viscous spinner can rotate at different speeds and in either the same or different directions. Adjusting the differential rotation rate between the vessel and spinner results in a controllable hydrodynamic focusing force. The resultant hydrodynamic force suspends the cells in a low-shear fluid environment that supports the formation of delicate three-dimensional tissue assemblies. Both suspension and anchorage-dependent cells have been successfully cultured.
Recent Development in Process Control for Aluminum Cold Rolling: Features of the Fata Hunter’s hSystem®
Authors: Cattelino Pier Michele , Licata Corrado , Rèpaci Luigi
Published: December 2021

Aim of the present paper is to highlight Fata Hunter’s hSystem®, emphasizing its self adaptive capabilities, process simulation and control together with simulation techniques which allowed the system developers to set up and fine tune the whole automation package.

In the framework of the implementation of the automation package, and especially of level 2, particular attention has been put upon cold rolling process modelization. To this aspect the second part of this paper has been dedicated.
Improvement in Coiling Temperature Control of Soft Cooling Pattern
Authors: Yang Chia Ching , Chen Dong Ping , Chang Fu Hsiang , Chen Jui Kun , Hsieh Chin Mu
Published: December 2021

The coiling temperature control problem for soft cooling pattern was investigated in this study. It has been found that the abnormal coiling temperature control behavior was caused by the use of incorrect preset value of spray efficiency modifier and non-linearity in the spray efficiency when the cooling pattern was overridden. To solve this problem, a cooling pattern model is hence established. By calculating the ratio of cooling rate for soft cooling pattern, both the spray efficiency modifier as well as the equivalent spray quantity compensation multiplier for cooling pattern override has been derived. The coiling temperature control and model adaptation program was then revised by adding the compensation multiplier in case of cooling pattern override. After the revision of spray efficiency modifier and coiling temperature control program, it was noted that the coiling temperature control of soft cooling pattern was significantly improved.
A Versatile Thermal-Mechanical Model for Twin-Roll Casting
Authors: Tseng A. A. , Chaidilokpattanakul C. , Chen J. S.-J.
Published: December 2021

Twin-roll casting has been widely used for producing thin strips and sheets. In twin-roll casting, molten metal is fed into the gap of a pair of counter-rotating, water-cooled rolls. In this paper, the development of a semi-analytical model of the thermal-mechanical behavior is presented. A mechanical model is coupled with thermal models to predict roll pressure distribution and roll separating force. To demonstrate its versatility and reliability, the results predicted by this model are compared with experimental data available in the literature and good agreements have been found between this modeling results and experimental observation. Also, for given operating conditions and material properties, the closed-form relationship between productivity and strip thickness has been established.
Alternative Estimation of Optimal Frequency Using the Wave Speed for Metal Droplet Generation in Freeform Fabrication
Authors: Zhao B. S. , Lee M. H. , Tseng A. A.
Published: December 2021

A linear instability characteristic equation is developed to analyze wave propagation along a cylindrical liquid jet. It is pointed out by the solution of the equation that a perturbation to the jet propagates in either a stable or an unstable manner. In the case of stable propagation the wave speed is dispersive and is not equal to the jet velocity. In the case of unstable propagation, wave speed is equal to the jet velocity and the perturbation amplitude grows with the propagation. Optimal frequency of perturbation is obtained by the determination of the maximum growth rate of disturbance with the derived equation. Experimental result is in good agreement with the predicted value in the generation of uniform droplets.
Fit Quality Evaluation and Fit Capability Analysis
Authors: Zhang Y. , Fang X. Daniel
Published: December 2021

A new measure for evaluating fit quality of mating parts via Fit Capability Indices (FCIs) is introduced as an interface between fit quality and process control of the mating parts. Fit Capability Analysis method is discussed based on the relationship between FCIs and Process Capability Indices (PCIs). A new statistical tolerancing approach for assuring predetermined fit quality is developed on the basis of fit quality evaluation measures and fit capability analysis, which can be used as a guideline to process design and process monitoring of the mating parts.
Probe Imaging Vision Coordinate Measuring System Using a Single Camera
Authors: Zhang Zhijiang , Yu Yingjie , Che Rensheng
Published: December 2021

The study describes a new vision coordinate measuring system-probe imaging vision coordinate measuring system using a single camera. In this system, a hand-held probe is used to contact the measured surface, some of which may be hidden from the view of camera. By analyzing the changes in the images of some known characteristic points on the hand-held probe 3-D coordinate measurement is realized. This paper proposes a measurement system model and an iteration technique to find its solution. Furthermore, the validity of the proposed measuring system is confirmed by experiments.
Material Properties as Indicators of Machining Behavior
Authors: Stevenson Robin
Published: December 2021

This paper demonstrates that the material properties developed using conventional material test procedures can be consistent with those developed during machining. However if extensive extrapolation is required to develop the high strain/high strain rate/high temperature data characteristic of machining, it is important to ensure that no change in deformation mechanism occurs over the extrapolation range. If such a mechanism change does occur the extrapolated data will be invalid.
A Model for the Tribo-Contact and Heat Distribution When Turning With Coated Carbide Inserts
Authors: Grzesik Wit , Nieslony Piotr
Published: December 2021

The orthogonal machining process when end turning medium carbon and austenitic stainless steels with cemented WC-Co tools coated with single-layer (TiC), two-layer (TiC/TiN), and three-layer (TiC/Al2O3/TiN) hard thin films was investigated. Extensive experimental investigations including the thermal, mechanical and tribological responses of the tribo-contact between the coating-substrate system and the chip, under different cutting conditions, were carried out. The study sheds light on the cutting forces, the interface temperatures and the tribo-contact conditions, including the fxictional heat flux conducting into either the chip or the insert, the mean coefficient of sliding friction and the contact loads exerted on the tool rake face. Finally, it was demonstrated how the intrinsic coating properties control the heat flux flowing into both components of such a closed tribo-system and the mechanical stresses on the contact area.
Profile Measurement of a Curved Workpiece by the Fuzzy Control of Sensor Positioning
Authors: Shiraishi Masatake , Yang Gongjun
Published: December 2021

A laser displacement sensor which has a resolution of 0.5 μm was used to determine the measurement of a curved workpiece profile in turning. This sensor is attached to a specially designed stage and is operated by three motors which are controlled by a fuzzy control algorithm. The experimental results show that the measuring system can be applied to workpieces having inclination angles of up to around 45°. The proposed measuring system has a practical measuring accuracy to within ten micrometers.
Development of a Grating Interferometer With Application to HDD Servo-Track Writing
Authors: Garner Harry D. , Lee Kok-Meng , Guo Lin
Published: December 2021

The development of a grating interferometer with application to the angular measurement of a hard disk drive actuator arm for application to the servo-track writing process is presented. A brief discussion of the operating principle of the grating interferometer is presented. This principle is then extended to the case of the measurement of the angular displacement of a hard disk drive actuator arm. A vector based diffraction technique has also been developed as a tool for visualization and analysis of the grating interferometer design. Finally, experimental setups and results from an implementation of the grating interferometer design are presented and discussed.
Coil Winding Tension Control
Authors: Hong Shane Y. , Jun SeongChan , Bordner Mark , Fair Roderick , Weatherbie Chris
Published: December 2021

This paper analyzes the current coil-winding machine to determine the wire tension occurring at various locations along the winding apparatus. The goal is to make possible design improvements for better wire tension control at the armature to prevent wire breakage and to enable high-speed winding. A typical commercial winding machine was analyzed. The computer simulation result suggests design modification is needed. Three new design concepts are presented. In the new designs, the path of the flier end pulley is no longer fixed. This allows the flier arm to deflect in response to tension fluctuations to achieve a more uniform tension during the winding process.
Residual Stress and Sub-Surface Flow in Finish Hard Turned AISI 4340 and 52100 Steels: A Comparative Study
Authors: Ramesh Anand , Thiele Jeffrey D. , Melkote Shreyes N.
Published: December 2021

This paper presents the results of an experimental study intended to compare the surface integrity of finish hard turned AISI 4340 and 52100 steels (57 Rc). Specifically, the paper addresses residual stresses, white layer formation and workpiece sub-surface plastic flow in hard turning of AISI 4340 by varying the feed rate and the tool cutting edge geometry. The results are compared with those obtained for AISI 52100 steel under identical conditions in a previous study (Thiele and Melkote, 1999a-b). In contrast to AISI 52100, no white layers were produced in AISI 4340 when cutting at low feed rates with a chamfered tool. Also, unlike AISI 52100, no clear evidence of an over-tempered layer was found in AISI 4340 steel under all conditions studied. Surface residual stresses in AISI 4340 steel were more compressive than AISI 52100 steel, whereas the magnitude and depth of the peak compressive residual stress tended to be greater for AISI 52100 steel. These observations are attributed to the different mechanical, thermal, and metallurgical responses of the two hardened steel alloys to machining, and are in part due to the significant difference in the carbon content of the two alloys.
Fixture Configuration Design Based on Topology Optimization
Authors: Liu Jinling , Hu S. Jack , Yuan Jingxia
Published: December 2021

This paper proposes a new approach to fixture configuration optimization. This approach is based on the concept of topology optimization of mechanical structures. Unlike existing techniques of fixture configuration optimization, this approach yields the optimal fixture topology by optimizing the fixture material distribution in a design domain, which surrounds the workpiece to be supported. Two methods, discrete density method and continuous density method, are used to optimize fixture topology. Application examples are given to validate these methods and to further illustrate the idea of fixture topology optimization. Compared with existing fixture configuration optimization techniques, the approach presented in this paper optimizes the fixture topology, rather than the number and/or placement of locators.
Modeling of Hydraulic Systems for Hardware-in-the-Loop Simulation: A Methodology Proposal
Authors: Ferreira Jorge A. , de Oliveira João E. , Costa Vitor A.
Published: December 2021

The present paper proposes a methodology to organize model libraries of electro-hydraulic components. This methodology holds in the association of an object oriented modeling, equation based, language for model structure description, with a graphical formalism suitable for the dynamic behavior description of reactive hybrid systems. That is, a recent general purpose language for physical modeling, called Modelica, is used to develop object-oriented libraries of models for different physical domains; the hierarchical description of the dynamic behavior of each model is obtained by means of the Statecharts formalism.

With the method proposed, complex models are built by model interconnection schemes; it is possible to organize the models for different complexity levels adapting them for distinct simulations (real-time or off-line), by refining their behavior using the Statecharts graphical formalism.

The developed hydraulic models, once compiled into C-code, are assembled as a whole application, and executed by a digital signal processing card (DSP). The simulation task is based on hardware-in-the-loop techniques in such a way that the “virtual” hydraulic application is controlled by real hardware.
Research on a New Type of Flow Control System of Hydraulic Elevators With Car Speed Feedback
Authors: Xu Bing , Yang Huayong
Published: December 2021

This paper introduces an innovation design of flow control system for hydraulic elevators with car speed feedback. By measuring pulse signal emitted by photoelectric encoder mounted on the elevator car, a single-chip computer controls the electrohydraulic proportional integrated flow valve, then drives the elevator car by a hydraulic cylinder. With this set of single-chip computer control system, good speed performance of the elevator can be achieved. Furthermore, it has strong robustness against the disturbance of oil temperature variation, mechanical friction and other disturbance factors. In order to obtain better ride comfort and soft start of the elevator, PID control algorithm is also proposed. Some mathematical models both for static and dynamic states have been established, consequently simulation results are found to be in close agreement with the experimental results.
Innovative Design in Quality Engineering
Authors: Bzymek Zbigniew M. , Billatos Samir B.
Published: December 2021

Industry is currently evaluating hundreds of applications to innovate their products. The Theory of Inventive Problem Solving (TIPS) can help industry achieve this goal. It provides principles of standard thinking called inventive standards that are based on a limited number of physics phenomena and mathematics theories. Applying these principles of thinking would avoid generating undesirable solutions and approach desirable ones. The theory is very powerful and almost unlimited. The basic concept of TIPS is understanding the process of describing a product that would then leads to its development. It is best applied when there are strong conflicts that the designer has to resolve. For example, to design a tailor needle, we have to solve the eye conflict. The needle’s eye should be small enough to secure comfortable sewing and big enough to put the thread through. The objective of this paper is to discuss TIPS, describe its five levels of inventive tasks and develops a systematic procedure for its application. A case study is described that details the application from the conceptual design stage to the final inventive design stage.
Parametric Study of Reactive Melt Infiltration
Authors: Nelson Emily S. , Colella Phillip
Published: December 2021

Reactive melt infiltration is viewed as a promising means of achieving near-net shape manufacturing with quick processing time and at low cost. Since the reactants and products are, in general, of varying density, overall conservation of mass dictates that there is a force related to chemical conversion which can directly influence infiltration behavior. In effect, the driving pressure forces may compete with the forces from chemical conversion, affecting the advancement of the front. We have developed a two-dimensional numerical code to examine these effects, using reaction-formed silicon carbide as a model system for this process. We have examined a range of initial porosities, pore radii, and reaction rates in order to investigate their effects on infiltration dynamics.
Entropy: Part II — Thermodynamics and Perfect Order
Authors: Gyftopoulos Elias P.
Published: December 2021

Part II of this two-part paper refutes the beliefs about the statistical interpretation of thermodynamics, and the association of entropy with disorder that are summarized in Part I. The refutation of the statistical approach is based on either a nonstatistical unified quantum theory of mechanics and thermodynamics, or an almost equivalent, novel, nonquantal exposition of thermodynamics. Entropy is shown to be: (i) valid for any system (both macroscopic and microscopic, including one-particle systems), and any state (both thermodynamic or stable equilibrium, and not stable equilibrium); (ii) a measure of the quantum-theoretic pliable shape of the molecules of a system; and (iii) a monotonic indicator of order. In contrast to statistics which associates a thermodynamic equilibrium macrostate with the largest number of compatible microstates, the second law avers that, for each set of values of energy, volume, and amounts of constituents of either a macroscopic or a microscopic system, there exists one and only one thermodynamic or stable equilibrium state. So, even if Boltzmann’s definition were used, a thermodynamic equilibrium state is one of perfect order.
The New Theoretical Approach of Vortex Phenomenon
Authors: Kotelnikov Valeri I.
Published: December 2021

In this paper I present the results of my studies on a new explanation of the vortex (Ranque-Hilsch) tube’s phenomenon. It is new way of understanding this process. The vortex tube was discovered in 1930 by French physicist Georges Ranque. Hilsch was the first American engineer to develop this phenomenon into practical, effective cooling solutions for industrial applications and theoretical modeling and calculations.

Currently, the use of conventional vortex pipes is limited in engineering application because of their low thermodynamic efficiencies. Problems associated with these thermal limitation include the separation of gaseous condensate, the separation of liquified air, and more. Still, some technological studies on heat energy generation using new techniques and heat transformation devices should be conducted.

This paper addresses the subject of the Ranque-Hilsch vortex tube’s phenomenon explanation based on a vortex-exited oscillation. There is no previous work reported in the literature desdribing the temperature splitting model by wave generating process. The study was motivated by the heating and cooling phenomenon that occurs in the Ranque-Hilsch vortex tube.
Design Considerations and Modeling of a Hybrid Energy System
Authors: Ding J. J. , Al-Jumaily A. M. , Tapp B. A.
Published: December 2021

The design and modeling issues are discussed in detail regarding a project to develop a stable hybrid energy system. The energy system will be used to supply power for lighting pathways between buildings on the campus of an educational institution. The system must be cost-effective, self sustained, and make full utilization of the wind, solar and hydro potentials that are available locally. The planned system was modeled and analyzed by making use of computer simulations based on the data collected over the past three years. This paper presents the modeling of the hybrid system over a global 12-month period by using a computer simulation software Stella II. Within this period the battery charging and energy consumption will complete a full cycle at a macro level. The analyses and modeling will be used together to provide a rationale for a proposal to be made to the local government departments and agencies to implement the energy system on campus. An additional outcome from implementing this hybrid energy system will be the benefit for engineering educational purposes.
Operation Diagnosis of a Combined Cycle Based on the Structural Theory of Thermoeconomics
Authors: Correas Luis , Martínez Ángel , Valero Antonio
Published: December 2021

Diagnosis of the performance of energy was theoretically developed based on the Structural Theory (Valero, Serra and Lozano, 1993), and traditionally Thermoeconomics have usually been applied to the design of power plants and comparison between alternatives. However, the application of thermoeconomic techniques to actual power plants has always to face the generally poor quality of measurement readings from the standard field instrumentation as an unavoidable first step. The proposed methodology focuses on measurement uncertainty estimation and performance calculation by means of data reconciliation techniques, in order to obtain the most confident plant balance upon the available instrumentation.

The formulation of the Structural Theory has been applied to a combined cycle, where the Fuel-Product relationships at the component level must be optimally defined for a correct malfunction interpretation. This set of relationships determines the ability to diagnose and the level of the diagnostics obtained.

The paper reports the application of the methodology to a 280 MW rated combined cycle, where performance diagnosis is illustrated with results from a collection of actual operation data sets. The results show that data reconciliation yields sufficient accuracy to conduct a thermoeconomic analysis, and how the estimated impact on fuel correlates with physical causes. Hence the feasibility of thermoeconomic analysis of plant operation is demonstrated.
Sensitivity of Natural Gas HCCI Combustion to Fuel and Operating Parameters Using Detailed Kinetic Modeling
Authors: Flowers Daniel , Aceves Salvador , Westbrook Charles K. , Smith J. Ray , Dibble Robert
Published: December 2021

This paper uses the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to analyze natural gas HCCI combustion in an engine. The HCT code has been modified to better represent the conditions existing inside an engine, including a wall heat transfer correlation. Combustion control and low power output per displacement remain as two of the biggest challenges to obtaining satisfactory performance out of an HCCI engine, and these are addressed in this paper.

The paper considers the effect of natural gas composition on HCCI combustion, and then explores three control strategies for HCCI engines: DME (dimethyl ether) addition, intake heating and hot EGR addition. The results show that HCCI combustion is sensitive to natural gas composition, and an active control may be required to compensate for possible changes in composition. The three control strategies being considered have a significant effect in changing the combustion parameters for the engine, and should be able to control HCCI combustion.
The Minimum Separation Work for Desalination Processes
Authors: Çerçi Yunus , Çengel Yunus A. , Wood Byard
Published: December 2021

A general relation is obtained for the minimum work input requirement for desalination processes using the second-law of thermodynamics. The relation developed can be used to determine the minimum work input for any salinity of the incoming water, and the recovery ratio. It is also shown that there is a lower and an upper limit for the minimum work, corresponding to recovery ratios of 0% and 100%, respectively. The minimum work input per unit mass of fresh water produced is determined for various salinities of incoming water, and the salinities of fresh water produced, and the results are tabulated and plotted. It is shown that the minimum work is a strong function of salinity, and increases with salinity and the recovery ratio. It is also shown that the minimum work input requirement remains fairly constant for recovery ratios of up to about 80%; the minimum work increases drastically at high recovery ratios; and an optimum value of recovery ratio exists to minimize the power consumption of actual desalination plants. But the value of this optimum recovery ratio decreases with increasing salinity of the incoming saline water. The results presented in this paper can be used as a basis to evaluate the performance of actual desalination plants.
Exergy as a Direct Measure of Environmental Impact
Authors: Sciubba Enrico
Published: December 2021

This paper describes an original approach to the evaluation of the influence of environmental pollution reduction measures on the energetic balance of conversion processes and systems. The quantifier taken to represent this influence is based on an extended representation of the exergy flow diagram of the process. The approach constitutes both a synthesis and a substantial extension of two different methods recently proposed by several independent Research Groups [6,8,15,30], with the purpose of providing Process Designers a general framework to include into their Design Procedures the engineering effects of effluents clean-up. The method presented here provides indeed such a coherent and consistent framework for evaluating environmental externalities, and at the same time constitutes a rational and theoretical basis which can be used to assess present and future pollution reduction technologies and policies. The paper begins with a brief summary of the existing state-of-the-art of environmental accounting techniques is given. It is then argued that some of the issues which are difficult to address with the present Thermoeconomic theory of value can be resolved in a straightforward manner by Extended Exergy Accounting (“EEA” in the following) methods. The importance of selecting the proper control volume (the portion of the biosphere affected by the system) and the correct time scale (the time span which the analysis must cover) are also discussed, and it is shown that their choice strongly affects the outcome of any environmental analysis. As an example of application, a standard cogeneration process is discussed in some detail, albeit at a rather general level.
Effective Yielding Characterization of Ductile Matrix Composites Containing Aligned Spheroidal Particles
Authors: Sun L. Z. , Ju J. W.
Published: December 2021

The effective yielding characterization of ductile matrix composites containing randomly located yet unidirectionally aligned elastic spheroidal reinforcements is investigated. The ensemble-volume averaging procedure is employed to micromechanically derive the effective yield function of composites based on the probabilistic spatial distribution of aligned spheroidal particles and the particle-matrix interaction. The proposed effective yield surfaces of composites are shown to be convex. The initial effective yield criterion of composites under axisymmetric loading is specifically discussed.
Ultrasonic Detection of Fatigue Cracks by Thermoelastic Modulation
Authors: Yan Zhongyu , Nagy Peter B.
Published: December 2021

Pulsed infrared laser irradiation was used to positively identify small fatigue cracks on the surface of fatigue damaged 2024 Al and Ti-6Al-4V specimens. The resulting transient thermoelastic deformation perceptibly changes the opening of partially closed surface cracks without affecting other scatterers, such as surface grooves, corrosion pits, coarse grains, etc., that might hide the fatigue crack from ultrasonic detection. We found that this method, which is very effective in 2024 aluminum alloy, must be modified in order to successfully adapt it to Ti-6Al-4V titanium alloy, where significant thermo-optical modulation occurs even from straight corners or open notches. This spurious modulation is caused by direct thermal modulation of the sound velocity in the intact material rather than thermal stresses via crack closure. It was found that the modified thermo-optical modulation method can increase the detectability of hidden fatigue cracks in 2024 Al and Ti-6Al-4V specimens by approximately one order of magnitude.
Mixed Mode Stress Singularities in Anisotropic Composites
Authors: Yin Wan-Lee
Published: December 2021

Multi-material wedges composed of fully anisotropic elastic sectors generally show intrinsic coupling of the anti-plane and in-plane modes of deformation. Each anisotropic sector has three complex conjugate pairs of material eigensolutions whose form of expression depends on five distinct types of anisotropic materials. Continuity of the displacements and the tractions across the sector interfaces and the traction-free conditions on two exterior boundary edges determine an infinite sequence of eigenvalues and eigensolutions of the multi-material wedge. These eigensolutions are linearly combined to match the traction-boundary data (generated by global finite element analysis of the structure) on a circular path encircling the singularity. The analysis method is applied to a bimaterial wedge near the free edge of a four-layer angle-ply laminate, and to a trimaterial wedge surrounding the tip of an embedded oblique crack in a three-layer composite. Under a uniform temperature load, the elasticity solution based on the eigenseries yields interfacial stresses that are significantly different from the asymptotic solution (given by the first term of the eigenseries), even as the distance from the singularity decreases to subatomic scales. Similar observations have been found previously for isotropic and orthotropic multi-material wedges. This raises serious questions with regard to characterizing the criticality of stress singularity exclusively in terms of the asymptotic solution and the associated stress intensity factors or generalized stress intensity factors.
Postbuckling and Growth Behavior of Face-Sheet Delaminations in Sandwich Composites
Authors: Kadomateas George A.
Published: December 2021

A bending load on a sandwich beam consisting of two fiber-reinforced sheets (skins) separated by a low stiffness core is equivalent to a compressive force on one face and a tensile force on the other. Should an interface crack between the layers of the composite face-sheet or between the core and the composite face-sheet exists on the compressively loaded face, local buckling and subsequently growth of this interface crack (delamination) may occur. This may also naturally occur under pure compression. In this study, the buckling, postbuckling and delamination growth behavior is studied through a procedure that is based on the large deflections of the delaminated layer. First, the solution is derived for the postbuckled states by using the elastica theory to model the large deflections of the thin delaminated layer and the sandwich beam theory (for unsymmetric sections) that includes transverse shear, to model the (relatively modest) deflections of the rest of the structure. This postbuckling solution is subsequently used to study the growth of the mixed mode interface crack through an energy release rate approach. The consequences of the elastic mismatch between core and face sheet are discussed and illustrative results are presented for several sandwich construction configurations.