bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of the Core and Shell on the Mechanical Response of Aging Vertebral Body
Authors: Overaker David W. , Langrana Noshir A. , Cuitiño Alberto M.
Published: January 2022

A 3D cellular solid model was used for the trabecular core of a whole vertebral body model to study the load bearing role of the two components: shell and core. Age related changes in the trabecular architecture were considered and the effects of osteoporosis on the load sharing behavior was addressed.
Load Sharing Comparison of a Rigid vs. a Hinged Device in the Stabilized Lumbar Motion Segment: A Finite Element Study
Authors: Goel Vijay K. , Konz Regina J. , Chang Hsiung-Tsai , Grosland Nicole M. , Grobler Leon J. , Chesmel Kathleen D.
Published: January 2022

This study investigated the dynamic load-sharing ability of a rigid versus a hinged pedicle screw-rod system using finite element analysis. A three-dimensional finite element model (FEM) of an intact L3-L4 motion segment was used in the investigation. The model was modified to incorporate both the rigid screw-rod device and the hinged screw-rod device. Both models were run for 800 N compression, 10 N-m flexion, and 10 N-m of extension. The loads through the nucleus of the intervertebral disc and the corresponding loads through the device were determined for each case. Additionally, the axial displacement of L3 and the flexion rotation of L3 with respect to L4 were determined. Both screw-rod devices provided stability to a destabilized spinal segment. However, the rigid device system allowed for slightly greater flexion rotation. Furthermore, the hinged pedicle screw-rod system offers a design more likely to promote increased load sharing without sacrificing construct stability, as compared to an equivalent rigid system.
Surface Response of Isokinetic Lower-Extremity Joint Strength: Towards the Evaluation of Dynamic Human Performance
Authors: Khalaf Kinda A. , Parnianpour Mohamad , Karakostas Tasos
Published: January 2022

The dynamic strength surface response was modeled for the ankle, knee, and hip joints of twenty normal subjects Such representation may be used as a “performance capacity envelope” to comprehensively characterize an individual’s dynamic joint strength performance. Potential applications cover a wide spectrum ranging from rehabilitation to ergonomic and biomechanical applications.
Kinematic Characterization and Radiographic Evaluation of Elbow Joint Rotation
Authors: Bottlang Michael , Marsh J. L. , Brown T. D.
Published: January 2022

Since the elbow is the articulation that most closely resembles a perfect hinge joint in the human, a number of operative techniques have emerged that impose an artificial hinge to the elbow joint. Currently these include total elbow arthroplasty, articulated external fixation, and distraction arthroplasty (Morrey, 1993). While the success of these treatment modalities highly depends on precise replication of the normal elbow motion by the imposed artificial hinge, there remain conflicting reports on physiologic elbow joint kinematics. Furthermore, no detailed analysis of radiographic landmarks describing the location of the elbow axis is available to date. Such data would allow more precise alignment of the artificial hinge with the elbow rotation axis in an operative setting.
A Cadaveric Foot Model for Posterior Tibial Tendon Dysfunction
Authors: Otis James C. , Kenneally Sharon M. , Hansen Matthew L. , Deland Jonathan T.
Published: January 2022

Posterior tibial tendon dysfunction (PTTD) is a significant foot disorder in which the posterior tibial tendon becomes inflamed and painful and loses its integrity. As a result, the posterior tibialis muscle/tendon unit becomes dysfunctional and, over the long term, the foot acquires a flatfoot deformity. Ideally, one would like to treat the problem early on and prevent the deformity from occurring. However, treatment to restore muscle balance in the foot in the early stages of the disorder have met with minimal success with patients eventually requiring fusions to treat the deformity and relieve pain. Currently no adequate models exist for studying the efficacy of treatment. A cadaveric foot model has been developed which simulates the muscle imbalance. The model can be used to investigate the biomechanical efficacy of surgical treatments used in early stage disease, prior to the occurrence of deformity. The model utilizes medial arch strain and talonavicular joint rotation as outcome measures.
Static and Fatigue Response Measurement of Various Fixation Systems Under Combined Loads
Authors: Patenaude O. , Shirazi-Adl A. , Dammak M. , Zukor D. J.
Published: January 2022

In arthritic joints, prostheses are used to replace degenerated articular surfaces thereby relieving the pain and gaining the near-normal function of the joint. The long-term performance of joint replacement systems depends, amongst others, on the short-term fixation stability of the prostheses. Excessive motions at the bone/porous-surfaced metal interface are generally recognized as a crucial factor to limit bone proliferation into surface pores of implants, resulting in fibrous ingrowth. Recent studies have identified relative micromotions of ∼20–40μm to be compatible with the bone ingrowth while larger motions are associated with less stable bone ingrowth and the formation of the fibrous tissue around the implant [1–3]. In recent years, periprosthetic osteolysis due to the wear debris produced from the implant bearing surfaces has been identified as the leading problem in total joint arthroplasty. To reduce the wear debris, substantial research studies have been and are being performed on the development of surface treatments and new materials for more resistant bearing surfaces. Despite the current general recognition of particulate debris as the principal cause of implant failures, the synergy between the implant motion and wear debris mechanism in the formation of periprosthetic fibrous membranes has only recently been stressed [4]. To provide initial and long-term stability of tibial components, the existing implant designs utilize a wide range of configurations with different number of screws and posts. We have compared the static fixation response of a metal plate resting on a polyurethane block with or without screws and posts under single symmetric/eccentric axial compression loads of up to 1000N [5], In an artificial knee joint, the transmitted articular forces are often inclined generating shear and torsional load components as well. Moreover, the fatigue response was not considered. To overcome these shortcomings of our earlier studies, the current work was set to: -measure the fixation response of a metal plate on top of a polyurethane block for designs with two bone screws or two smooth-surfaced posts under an inclined eccentric load resulting in 1000N axial compression and 250N shear force (the single plate with no fixation cannot be tested due to the destabilizing effect of the shear force which exceeds the frictional resistance); -measure the response of the plate fixated with a novel smooth-surfaced post with adjustable inclinations of nil, 1.5°, and 3°; and -investigate the fatigue response of various fixation systems under repetitive eccentric inclined for up to 4000 cycles at 1 Hz frequency.
Finite Element Analysis of Contact Stresses in Metal-Plastic Total Knee Replacement
Authors: Chu Taiming , Chen Jing , Pappas Michael
Published: January 2022

Clinical observation indicates that the polyethylene wear in replacement knee with metal to plastic articulation is a significant problem. The case studies (Knezevich et al., 1993) reinforce the concept that the design of the knee components is critical to minimize polyethylene wear and thus reduce the chances of subsequent failure. Many factors affect wear. They are, for example, contact surface configuration, material, surface finishing, loads, motion, temperature, lubrication, contaminants and previous use conditions. Among them, the essential factor is the contact surface configuration (Pappas, 1986). From the design viewpoint, avoiding high wear rates in a metal polyethylene articulation prosthesis is equal to avoiding a high contact stress in excess of the fatigue strength of the polyethylene. The aim of this study is to investigate the contact stress distribution on the tibial (bearing) component at different walking positions using the finite element method. Results can help to predict the wear potential of the tibial component.
A Viscoelastic Model for Finite Deformation of Soft Tissue
Authors: Hovey Chad B. , Kaplan Matthew L. , Heegaard Jean H.
Published: January 2022

The ubiquitous presence of soft tissue in the human body has provided significant motivation for researchers to model its behavior. Specifically, soft tissue models for cartilage have been extensively developed. The biphasic (Mow et al., 1984) model has provided a foundation for the understanding of cartilage behavior, grounded in a solid-fluid interaction point-of-view. Phenomenological approaches have also been made, borrowing developments from viscoelasticity and applying those models to biomechanics. Woo et al. (1980) discussed the viscoelastic properties of cartilage in the context of a quasi-linear theory.
Porohyperelastic Finite Element Models for Large Arteries Subjected to Cyclic Pressure
Authors: Simon B. R. , Liu J. , Kaufmann M. V. , Cordaro N. , Nichol J. , Baldwin A. L.
Published: January 2022

Recent research in vascular mechanics has addressed deformation and mobile fluid flux in the arterial wall using poroelastic finite element models (FEMs) of undrained and steady-state conditions. However, arteries are subjected to pulsatile pressures and axial tethering. Very little attention has been given to cyclic (pulsatile) arterial wall response. We will use our porohyperelastic (PHE) theory, material properties, and the ABAQUS FE program (Version 5.6) to simulate coupled structural-fluid transport in intact and de-endothelialized rabbit aortas subjected to “normal” as well as “hypertensive” idealized cardiac pressure cycles.
Finite Element Simulation of Stresses in Healing Cartilage Defects
Authors: Weiss Jeffrey A. , Moulis Patricia M. , Ayliffe H. Edward , Rosenberg Thomas D. , Cooley Vernon J.
Published: January 2022

Damage to the articular cartilage is an exceedingly common problem affecting the joints of millions of people. When the injury does not penetrate the subchondral bone, the outcome of biological healing is poor and eventually leads to the degeneration of the articular surface. In young patients, small focal defects are often treated using marrow-stimulation techniques, including subchondral drilling (Tippet, 1996), microfracture (Tippet, 1996) and abrasion arthroplasty (Johnson, 1996). In these procedures, the torn or compromised cartilage is removed to expose the underlying bone and a rim of healthy cartilage is defined surrounding the defect hole. This is followed by drilling, puncturing or abrading the underlying bone to stimulate an inflammatory response and/or generate a blood clot within the defect. Clinical results suggest that the relative success of these procedures (i.e. the extent and quality of defect fill-in) depends on the level of strain experienced by the healing tissue during the early period following the procedure. Although the state of compressive and shear strain within and around the chondral defect is presumed to depend on the size and location of the defect, the relationship between these factors is not well documented. A finite element model of the medial compartment of the knee was constructed to examine the effect of defect size and location on predicted strains within and around the defect.
Direct Measurements of Hydraulic Permeability Coefficients of Cartilaginous Tissues
Authors: Gu W. Y. , Mao X. G. , Rawlins B. A.
Published: January 2022

Fluid is a major component of cartilaginous tissues. Its transport is primarily governed by the hydraulic permeability coefficient of the tissue. The hydraulic permeability coefficient is important to the understanding of the transport processes of interstitial water and ions [e.g., Gu et al, 1993] and the viscoelastic behavior of the tissue [e.g., Mow et al, 1980; Setton et al, 1993]. However, the hydraulic permeability coefficients of these tissues are extremely low and difficult to quantify precisely. Studies in the literature report on the determination of the hydraulic permeability of these tissues directly by measuring fluid flux corresponding to the applied pressure difference in a permeation experiment [Edwards, 1967; Mansour and Mow, 1976; Mansour and Matsumoto, 1998; Maroudas and Bullough, 1968; McCutchen, 1962] or indirectly by curvefitting experimental data from confined compression or indentation tests using the biphasic theory[e.g., Athanasiou et al, 1991; Best et al, 1994; Drost et al, 1995; Houben et al, 1997, Iatridis et al, 1997; Mak et al, 1987; Mansour and Matsumoto, 1998; Mow et al, 1980; Setton et al, 1993]. Recently, Gu and co-workers (1998) reported that the permeability coefficient of human anulus fibrosus determined directly was one order of magnitude greater than that determined indirectly [e.g. Best et al, 1994, Drost et al, 1995, Houben et al, 1997, Iatridis et al, 1997]. To address this discrepancy, we investigated the hydraulic permeability coefficients of human lumbar anulus fibrosus and bovine articular cartilage using a new technique developed by Gu and co-workers (1998). The hydraulic permeability coefficient of human anulus fibrosus was compared to that of bovine articular cartilage measured under the same testing conditions.
Biomechanical Effects of Intra-Specimen Variations in Trabecular Thickness: A Three-Dimensional Finite Element Study
Authors: Yeh Oscar C. , Keaveny Tony M.
Published: January 2022

Underlying the importance of trabecular architecture on whole bone strength, osteoporosis has recently been defined as “a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk” [1]. Architectural measures, such as the fabric tensor and connectivity, can explain 20%–30% of the inter-specimen variance in modulus of trabecular bone [2–4]. It has also been observed that apparent density alone does not fully differentiate clinically between atraumatic fracture and non-fracture subjects [5] and that bone strength is not increased in response to fluoride treatments despite an increase in bone mass [6], both suggestive of the role of architecture on the mechanical properties of trabecular bone. Most previous studies on architecture have focused on inter-specimen variations in architecture, whereas intra-specimen variations have received little attention. Thus, the intra-specimen variation in trabecular thickness is considered in this study as an additional candidate parameter for assessing osteoporosis and the effectiveness of drug treatments.
Surgical Simulation of Tendon Transfers to Augment Lower Extremity Function With Functional Neuromuscular Stimulation
Authors: Zhao Weifeng , Triolo Ronald J. , Wibowo Michael , Bhadra Niloy
Published: January 2022

A musculoskeletal model was used to study tendon transfer surgery in order to decouple hip extension and knee flexion in lower extremity FNS applications. Effects of tendon transfer location and shortening length were quantitatively examined based on the resulting moment-generating capacity. Simulation results have shown that moment arm is not sensitive to the transfer locations. Appropriate shortening is the key to counteract the tendon slack caused by the transplantation and to achieve maximal hip extension strength.
Application of Nonlinear Stability Analyses to Study Human Standing/Balance
Authors: Wood Aaron J. , Reisinger Kim D.
Published: January 2022

Nonlinear dynamics analyses are utilized to explore some of the basic dynamics and stability of human standing/balance. Phase plane portraits, plots of angular velocity versus angular displacement, present kinematics of the system in a compact form and provide insight into the dynamics of the system. Poincaré maps depict the transient and steady-state motion, and provide information about the stability of the system. Five young adults with no known gait pathologies participated in this study. A motion analysis system and force plates were utilized to capture the displacements of each body segment and joint, and the shifting of body weight between feet. Participants were required to stand comfortably with one foot on each force plate. Phase plane portraits were constructed for each joint in each of the sagittal, frontal and transverse planes. Poincaré maps were constructed by identifying a shift in weight onto one foot and sampling the corresponding joint velocities at those times.
Accumulation of Microdamage With Increasing Strain in Bovine Trabecular Bone
Authors: Arthur Tara L. , Gibson Lorna J.
Published: January 2022

Microcracks are present in normal human bone, and microcracks are thought to be a stimulus for bone remodeling. When there is an imbalance between microcrack creation and repair, microdamage can accumulate and result in bone fracture.

Seventeen specimens were tested in monotonic compression to one of six total strain levels. Chelating fluorochromes were used to label cracks and distinguish between microdamage created before and during testing. Histology specimens were observed under epifluorescence for microdamage in the form of microcracks. The number of cracks, sum of the crack lengths, and frequency distribution were recorded for each specimen. Microdamage accumulated non-linearly with increasing total strain on the specimen, but the mean crack length remained the same with increasing damage.
Structure-Function Relationships for a Coralline Hydroxyapatite Bone Substitute
Authors: Haddock Sean M. , Debes Jack C. , Keaveny Tony M.
Published: January 2022

Coralline hydroxyapalite (Pro-Osteon 500, Interpore International, Irvine, CA) is an artificial bone substitute that has been approved by the FDA since 1993. Despite previous in vitro and animal studies on the mechanical behavior of coralline hydroxyapatite [1–3], its mechanical properties are not well understood. Further, the relationship between the microstructure and mechanical properties of coralline hydroxyapatite is unknown. Knowledge of this relationship is important in determining the optimal clinical use of this bone substitute.
Rheological Properties of Bovine Liver Tissue
Authors: Liu Zizhen , Bilston Lynne
Published: January 2022

Characterizing the rheological properties of liver tissue, especially within the linear viscoelastic region, is useful for investigating the behaviour of the tissue under mechanical loads. This paper reports three types of experiments of rheological properties of liver tissue that were carried out recently, including strain sweep oscillation, shear stress relaxation and strain controlled oscillation. These experiments were designed to investigate the following: a) the domain of linear viscoelasticity of liver tissue, b) the time dependent behavior of liver tissue, and c) the dynamic storage modulus and loss modulus. Fresh bovine liver tissues were used for the experiments. All the liver tissues were bathed in a 0.9% sodium chloride solution immediately after harvesting. The test samples were cut to a disk of diameter 20–30mm with 1.5–2.5mm thick. Several strain sweep oscillation tests were performed to measure the sample behavior at stepwise changing strain amplitude at 1 Hz frequency. The results showed that the linear viscoelastic limit of bovine liver tissue is of the order of 0.2% strain. The shear stress relaxation test indicated that there is no apparent long-term elastic modulus reached before 3000 seconds within the linear viscoelastic region. The dynamic storage modulus and loss modulus were obtained in the frequency range of 0.001–20 Hz.
Prediction of Postural Balance by Means of Zero Moment Point (ZMP)
Authors: Goswami Ambarish
Published: January 2022

Zero moment point (ZMP) is well-known in the robotics literature as an indicator of postural stability and has been successfully used to control anthropomorphic biped robots. In this paper we review the basics of ZMP, explain its behavior by means of planar point-mass models and full 3D extended rigid-body models, and show how it can be applied in the study of postural balance in the human.

ZMP is an easily understandable, intuitive, easy-to-use, and physically meaningful criterion for the prediction of balance in dynamic locomotion systems. ZMP may be defined as a point on the ground where the resultant rolling moment on the foot reduces to zero. In order for the foot not to roll, the point should be constrained within the footprint. We relate the foot moment with the dynamics of the body segments and derive the expression of ZMP. We demonstrate that the position of ZMP also indicates the magnitude of rolling moment and the direction of the impending roll. Being a dynamic criterion, ZMP is a function of the position, velocity and the acceleration of the body segments and is shown to be a general concept from which the center of pressure (CP) and the horizontal projection of center of mass (HCM) may be extracted as special cases.
A Method to Determine the Effect of the Individual Rotator Cuff Muscles to Dynamic Joint Stability of the Shoulder
Authors: Kim Kyu-Jung , Lee Seok-Beom , An Kai-Nan , Morrey Bernard F.
Published: January 2022

The prevalence of rotator cuff disease among the elderly population and the greatest incidence of acute dislocations will continue to provide challenging patient management decisions. Stability of the shoulder is critical to successful upper extremity function. The GH joint is stabilized by passive capsuloligamentous restraints as well as by active dynamic stabilizers through concavity compression. The compression of the convex humeral head (HH) into the concave glenoid fossa (GF) counteracts against translational shear forces (Matsen et. al 1994). The major compressive load across the joint is provided by the action of the surrounding musculature, especially the rotator cuff. The muscles may generate both compressive and shear force components as well as moments. The purpose of this study is to describe a new testing methodology of how to estimate the contribution of individual rotator cuff muscles to the dynamic stability of the GH joint at a given joint position.
Microcoaxial Electrode for Local Nitric Oxide Measurement in Biological Systems
Authors: Kitamura Yoshiichiro , Uzawa Tomoyuki , Oka Kotaro , Komai Yutaka , Ogawa Hiroto , Kobayashi Hirosuke , Takizawa Naosada , Tanishita Kazuo
Published: January 2022

A new nitric oxide (NO) selective electrode was developed. The tip diameter of the NO electrode is less than 10 μm. A working and a reference electrodes are located coaxially at the tip of the NO electrode. A stable NO donor SNAP (S-nitroso-N-acetyl-DL-penicillamine) and a putative NO scavenger hemoglobin (Hb) was used to examine the response of the electrode. Considering the instantaneous concentration of NO secretion previously reported in biological systems, 0.1, 1 μM NO solution was used to calibrate the electrode.

From the result of the test of the electrode with SNAP and Hb, we confirmed this microcoaxial NO electrode can detect NO released from SNAP directly and continuously. From the result of calibration of the electrode, good linearity was examined in sub-molar concentration range. It is expected to detect local NO concentration in biological systems with a high space resolution.
Circumferential Strain Around Femoral Cylinders due to Simulated Press-Fit Loading
Authors: Brown Christopher U. , Kish Vincent L. , Norman Timothy L.
Published: January 2022

An experimental model was developed to apply radial forces around a uniform cylinder of femoral bone to determine the short term strain response. Eight strain gages were applied at equal intervals around the circumference of the cylinder. No significant differences exist between the circumferential strain magnitudes of each cortical region, however, there is a trend for a difference between the posterior region and the other regions. Further analysis needs to be done to elucidate the relationship that may exist between the strain and the bone morphology and composition of the cortical regions.
Transient Discharge of Entrained Air From a Wound Roll
Authors: Keshavan M. B. , Wickert J. A.
Published: January 2022

As magnetic tape or other web-like material is wound onto a roll, air moving with the incoming stream and the roll becomes forced into the converging wedge at the stream’s point of tangency. The spiral-shaped air bearing so formed can extend many wraps into the roll’s interior. When the roll is subsequently brought to rest, the entrained air discharges from it, and the roll’s radius gradually decreases until all adjacent tape layers have come into direct contact. In the present paper, a model is developed for this transient discharge process, and for the rate at which the roll stabilizes following steady-state winding. Predictions of the model are compared with results from laboratory experiments in which the roll’s radius is measured through laser interferometry during the steady entrainment, and transient discharge, stages of winding. Parametric effects of the tape’s tension, speed, width, and surface roughness are specifically addressed with a view towards reducing the time required for the roll to stabilize.
Estimation of Distributions of Contact Stressess and Displacements Using Regularization Schemes
Authors: Kubo Shiro , Ohji Kiyotsugu
Published: January 2022

Estimation of tractions and displacements on inaccessible boundaries, such as contact areas of solids, can be regarded as an inverse boundary value problem. In this study finite-element based inverse analysis schemes with regularization were applied to the estimation of the distributions of tractions and displacements on contact areas. The finite element equation was rewritten in terms of unknown boundary values on the contact area using over-prescribed boundary values. This equation was solved for the boundary values on the contact area. Like many other inverse problems, this inverse problem was severely ill-conditioned and the estimated distributions were very sensitive to the over-prescribed boundary values used in the estimation. To overcome the ill-posedness of this boundary value inverse problem, the function expansion method and Tikhonov regularization were introduced in the finite element-based inverse analysis scheme. The number of terms in the function expansion and the smoothing parameter in Tikhonov regularization were regarded as regularization parameters in the inverse analysis. To determine the optimum value of these regularization parameters, the estimated error criterion and the AIC were introduced. The usefulness of the finite element-based inversion scheme was examined by numerical simulations. It was found that the distributions of tractions and displacements can be estimated reasonably even from noisy observations by using the finite-element based inverse analysis schemes with regularization. The optimum value of the regularization parameters can be estimated by the estimated error criterion or by the AIC.
Linear Buckle Analysis for Partially Buckled Webs
Authors: Loen Mark V.
Published: January 2022

Web processing requires that the web is stretched under tension between two processing rolls. When the processing rolls are misaligned or moved relative to each other, a web deflection is introduced which causes the web stress to change. Small roll misalignments or movements may cause large web stresses, yielding, and failure.

The web stress distribution and deflection can only be found if the buckled and unbuckled portions of the web are determined. This paper presents the assumptions and analytical method needed to find the boundary edge between the buckled and unbuckled portions of the web. Also, the method for analyzing the unbuckled portion of the web to determine the web end deflection, end rotation, and maximum stress is included.
Robust Damage-Mitigating Control of Mechanical Structures: Experimental Verification on a Test Apparatus
Authors: Zhang Hui , Ray Asok
Published: January 2022

The goal of damage-mitigating control is to achieve high performance of operating machinery without overstraining the mechanical structures and the potential benefit is an increase in the component service life with no significant loss of performance. This paper presents the design of a test apparatus, the synthesis of a damage-mitigating control system, and the results of experimentation where the objective is to demonstrate the concept of fatigue damage reduction as an extension of multivariable robust feedback control. The test apparatus is built upon a three-degree-of-freedom, two-input three-output mechanical structure. The methodology of the damage-mitigating control synthesis is built upon the principles of: (i) frequency-domain identification of the plant dynamics and modeling of uncertainties in the state-space setting; and (ii) robust control based on the H∞ approach by taking both plant dynamic performance and material degradation of structural components into consideration. Case studies on the test apparatus indicate that fatigue life of specimens can be substantially extended with no appreciable degradation in the dynamic performance of the mechanical system.
Enhancing Subjective Sensitivity to Vibrotactile Stimuli
Authors: Murray Anne M. , Klatzky Roberta L. , Khosla Pradeep K.
Published: January 2022

We demonstrate through a set of psychophysical experiments that the miniature voice coils we have selected for our vibrotactile glove design are capable of producing discriminablc vibrotactile information to a user. We examine three ways of modifying the vibration of the voice coil, by varying: 1) the amplitude of a sinusoidal signal at the optimal frequency (250–300Hz); 2) the frequency of a sinusoidal signal at the maximum (suprathreshold) amplitude; and 3) both the amplitude and the frequency of a sinusoidal signal. Through this work, we have found that a user’s sensitivity is significantly enhanced (at least 111%, p < 0.001) by modulating both the amplitude and the frequency of a sinusoidal signal. The increase in sensitivity may result in better discrimination of less intense stimuli. If this vibrotactile glove were used to convey touch and grip force information, this sensitivity enhancement could enable a user to control smaller grip forces better.
Human Perception of Friction in Haptic Interfaces
Authors: Lawrence Dale A. , Pao Lucy Y. , Dougherty Anne M. , Pavlou Yiannis , Brown Shane W. , Wallace Stephen A.
Published: January 2022

Resistance to motion in haptic interfaces causes unwanted corruption of rendered data. Quantifying perceptual thresholds of this friction is important as a quality measure and design metric for these devices. Key difficulties in determining these perceptual thresholds are identified, and a strategy based on modeling activation in psychophysical channels is proposed to overcome these difficulties. An experiment is conducted to determine sensory thresholds for a particular haptic interface using pairs of friction-reducing force controllers to vary levels of residual friction presented to users. Results indicate the need for detailed channel-specific activation models of the type proposed.
Improved Uncertain Transfer Function Synthesis and Analysis Using Bond Graphs and Transmission Matrices
Authors: Wilson Bruce H. , Eryilmaz Bora
Published: January 2022

Various robust control applications require the value set of an uncertain transfer function, G(s, q), which is the complex-plane region {G(jω,q): q ∈ Q} where q is a vector of uncertain parameters. When the transfer function can be decomposed into a tree structure with disjoint sets of uncertain parameters, the value set synthesis process is simplified. A recently published bond-graph-based technique provides the means to synthesize a tree-structured transfer function (tstf). However, the method is difficult to use when the sensor-actuator pair is not collocated or nearly collocated. The present work overcomes this limitation by employing bond graph transmission operators to couple the input/output variables. Using the operators, we provide a method to synthesize a tstf, regardless of the separation of the sensor-actuator pair. A comprehensive example demonstrates transfer function synthesis using the operators. The technique provided here significantly augments the class of systems for which tstfs can be readily synthesized.
Mechatronics: A Thread in the Mechanical Engineering Undergraduate Curriculum
Authors: Murray William R. , Garbini Joseph L.
Published: January 2022

Mechatronics is the synergistic combination of mechanical, electrical, and computer technologies in the design of complex products and processes. Recent rapid growth of mechatronics as an area of engineering has given rise to a significant demand for mechatronics engineers. At the university level, engineering programs have emerged that help meet this need by producing engineering graduates who are capable, well-rounded mechatronics designers.

One such program is the multi-course guided curriculum in mechatronics that is available to students in their senior year in the Mechanical Engineering Department at the University of Washington. Described in this paper are that mechatronics program as a whole, the curriculum into which it fits, the individual constituent courses, and our observations after offering this program for two years.
Discretizors and Interpolators for Five-Axis CNC Machines
Authors: Sarma Radha , Rao Aarthi
Published: January 2022

Discretization and interpolation of curves are two frequently adopted practices when machining complex curves using computer numerically controlled (CNC) machines. Both practices stem from the need to sample curves at discrete time intervals corresponding to the sampling period of the CNC machine. This paper proposes new techniques for discretization and interpolation that account for the change of tool orientations in five-axis machining. Firstly, the method for discretization proposed in this paper is based on sampling the curves such that specified contour, feedrate, and orientation errors are not exceeded. Secondly, the interpolator proposed in this paper will be able to avoid excessive angular velocities arising from sampling the curves based on the feedrate alone.
Stability and Control of Linear Motor Feed Drives for the End Milling Process
Authors: McNab Robert J. , Tsao Tsu-Chin
Published: January 2022

Linear motor direct drive actuators are implemented as feed drives for the end milling machining process. An H∞ optimal feedback controller is designed and analyzed for performance, stability, and robust stability. A simplified cutting process model is presented for use in system stability analysis. Because of uncertainty in the cutting process model and the multivariable nature of the system when cutting is taking place, a μ analysis approach is taken to establish stability boundaries for the machine parameters. Experimental results verifying the cutting process model, examining the feedback controller performance, and verifying the accuracy of the robust stability analysis are presented.
Open Architecture Based Framework in Integrated Precision Machining System
Authors: Lee Yoon , Dornfeld David A. , Wright Paul K.
Published: January 2022

This paper introduces a current effort in the application of an open architecture (OA) control system in precision machining at Berkeley’s Laboratory for Manufacturing Automation (LMA). In the first part of this paper, issues in precision machining relative to the application of OA control systems and a higher level framework for conceptualizing the integration of a precision manufacturing process using an existing OA manufacturing scheme is proposed. In the second part, the first level of implementation of an open architecture controller system on a single point diamond turning machine is presented.
Developments in Nonlinear Control System Synthesis Research
Authors: Garg Devendra P.
Published: January 2022

The control of nonlinear systems presents a particularly challenging problem for engineers since the dynamics of such systems is inherently complex. The principle of superposition does not hold, and the dynamic response is generally initial condition specific. In 1978, the ASME’s Dynamic Systems and Control Division had published a monograph entitled Nonlinear System Analysis and Synthesis: Vol. 1 - Fundamental Principles (Edited by J. Karl Hedrick and Henry M. Paynter), which consisted of five chapters. The titles and authors of the first four chapters, respectively, were Some Fundamental Principles of Nonlinear Systems by Andrew U. Meyer; Stability of Nonlinear Systems by Kumapati S. Narendra; Nonlinear System Response: Classical Techniques for Unforced Response by Henry M. Paynter; and Nonlinear System Response: Quasi-Linearization Methods by J. Karl Hedrick. The author of the present paper has had a long standing interest in the controller synthesis research [see, for example, References 01–08]. He was also the contributor of the fifth and final chapter entitled Nonlinear Controller Synthesis, in that monograph. A number of innovative approaches have been developed for controller synthesis since the publication of the ASME monograph, particularly under the sponsorship of National Science Foundation’s Dynamic Systems and Control Program. This paper traces some of the recent developments in the area of nonlinear control system synthesis. These developments are illustrated with a few specific examples of techniques advanced during the course of research sponsored by NSF.
A 2D Biomechanical Model of the Human Tongue
Authors: Payan Yohan
Published: January 2022

This study aims to evaluate the impact of anatomical, morphological and biomechanical properties of one of the main articulator, namely the tongue, onto the kinematic properties of speech movements. For this, a 2D biomechanical Finite Element model of the tongue was developed. It integrates four extrinsic muscles and three intrinsic ones. This model is controled according to the Equilibrium Point Hypothesis, proposed by Feldman (1966, 1986). The deformations of the model are computed, in order to simulate Vowel-to-Vowel transitions. The articulatory patterns synthesized with this model are then compared to data collected on a male native speaker of French. Emphasis is put on the potential influence of biomechanical tongue properties on to measurable kinematic features.
Improving the Performance of a Geophone Through Capacitive Position Sensing and Feedback
Authors: Barzilai Aaron , VanZandt Tom , Kenny Tom
Published: January 2022

This paper reports on the improved performance of a geo-phone obtained by measuring the displacement of its proof mass capacitively rather than inductively and operating the sensor as a closed loop system. A measurement of the displacement of the proof mass rather than the velocity measurement made with a conventional geophone provides better low frequency performance. As a result, a geophone can be considered for use in a broader array of applications. A capacitive geophone can operate in either an open loop or closed loop mode. This paper describes a closed loop geophone system with a frequency response similar to the state of the art Streckeisen seismometers.
On-Line Identification of Model Parameters for a Liquid Fuel Film Present in the Induction System of a Gasoline Engine
Authors: He Chuan , Chalhoub Nabil G.
Published: January 2022

Optimal efficiency of the three-way catalytic converter can only be achieved if the air-to-fuel ratio (AFR) is kept at the stoichiometric level. However, large excursions of the AFR have been observed during transient operations of port injection engines. These excursions are induced by the intake manifold filling, fueling strategy, wall-wetting and sensor dynamics. Therefore, to have tight control over the AFR, both air and fuel flows in the induction system must be accurately known.

This work focuses on the fuel transport characteristics within the induction system. It considers a first order fuel film model whose parameters are constantly updated by an on-line system identification scheme. A nonlinear engine model used herein as a test bed to assess the performance of the identification algorithm. The digital simulation results demonstrate the capability of the proposed approach in enhancing the accuracy of the fuel puddle model.
Learning From Operating Experience at the Department of Energy
Authors: Rollow T. A. , Marchese A. R. , Day R. E.
Published: January 2022

The Office of Environment Safety and Health (EH) within the Department of Energy (DOE) has a program for the analysis of facility operations. Tools used in this study include measures of safety, called “performance indicators,” which reports occurrences, and the identification of underlying causes of both desirable and undesirable events, referred to as “lessons learned.” The overall goal of the study is the development and continual improvement of a comprehensive integrated safety management system.
Safety Factors Relating to Monitored Compactor Operating Parameters
Authors: Etherton J. R. , Moore P. H. , Harris J. R. , Zeng S.
Published: January 2022

Recent NIOSH fatality investigations have shown that workers risk amputation and crush injury while attempting to clear jammed material from the loading chambers and feed chutes of operating baling and compacting equipment. A recent NIOSH study suggests that signals generated by strain gage transducers could be used to warn of impending jams. Strain gages placed at locations on the machine’s frame experiencing large deformations preceding jams would be used to trigger a visual or audible alarm. A system safety analysis using FaultrEASE software was conducted to describe the sources of variation in operating conditions that could confound the transducer response of the proposed safety device. Monitoring will require adequate signal conditioning to adjust for the effects of temperature differentials, vibration, electromagnetic interference, and other factors present in the indoor and outdoor operating environments typical for these machines.

An experimental study was also conducted. Readings were collected from strain gages bonded to an integral horizontal compactor container. Readings were taken once a day as the compactor was normally being filled. Independent variables included: gage site; gage length; relative amount of compactor fill; and gage orientation. The dependent variable was strain gage voltage response under normal compactor cycling. The strains that were indicated were clearly biaxial and dynamic. Varying gage length and location produced significantly different responses. Substantial changes in gage response were recorded as material volume increased in the container. Mechanical blocking of the platen and proper lockout/tagout should remain the primary control of hazardous energy to prevent baling-equipment-related amputation and crushing injury.
Risk Analysis and Bicycling Injuries
Authors: Ayres T. , Kost G. , Schmidt R. , Werner S. , Young D.
Published: January 2022

Risk analysis offers a powerful set of tools for evaluating product design and safety issues. In this paper, we use appropriate risk analysis techniques to examine the extent, nature, and source of injury risk associated with bicycles in the United States.
Passenger Rail Vehicle Dynamic Performance: Tests and Analysis Correlations
Authors: Samavedam Gopal , Gomes John , Warren Peter , Tsai Thomas
Published: January 2022

Passenger rail vehicles have to operate on a variety of track geometries: tangent, curved and spirals connecting tangents to constant radius curves. The maximum levels of vertical and lateral misalignment and the maximum amount of crosslevel variation that can be safely negotiated are important in safety evaluations.

The overall objective of this paper is to show that experimental characterization with detailed simulation can accurately predict the dynamic response of passenger rail vehicles in safe and unsafe operational regimes. The validation of the simulation tool is a part of the safety assessment methodology. Computer simulations of the vehicle dynamic response were formulated to incorporate the track flexibility.
Dominance Zone for J-A2 Characterization of Crack-Tip Fields and Size Requirements for Fracture Testing
Authors: Chao Yuh J. , Zhu X. K.
Published: January 2022

Using the J2 flow theory of plasticity and within the small-strain framework, full-field finite element solutions are obtained for both deep and shallow crack geometries of single edge notch bar under pure bending [SEN(B)] and central cracked panel in uniform tension [CC(T)]. These crack-tip stresses are compared with those in the HRR singularity fields and the J-A2 three-term asymptotic solutions at the same level of applied J. The comparison indicates that the size of the region dominated by the J-A2 three-term solution is much larger than that of the HRR field around the crack tip. Except for deep crack SEN(B) in low hardening material (e.g. n = 10 ) under fully plastic conditions, the numerical results near the crack tip in both SEN(B) and CC(T) match very well with the J-A2 three-term solutions in the area of interest 1 < r / (J / σ0) < 5 from well-contained to large scale plasticity. The implications of these results on the minimal specimen size requirements essential to a two-parameter fracture testing based on the J-A2 three-term asymptotic solution are then discussed.
Discrepancies Between High Temperature Fatigue Life Prediction Models
Authors: Moftakhar Abbas A.
Published: January 2022

One feature of creep fatigue data is the large amount of scatter present, even for test specimens taken from the same heat of material and tested under nominally identical conditions. This has led to considerable discrepancies between methods proposed during the last 40 years for fatigue life prediction of high temperature components. Presently, there is no general agreement on optimum approaches.

The inadequacy of the Manson-Coffin law for high temperature use is discussed. The frequency modified fatigue life model and the strain range partitioning method, two popular extensions of the Manson-Coffin law for high temperature use, are studied. Major differences in terms of mechanistic interpretations and mathematical formulations between these two models are investigated. Also, difficulties in the realistic application of these methods are studied and some simplified solutions are proposed.

The time-dependent damage rule of the ASME Boilerand Pressure Vessel Code is studied for its application to notched components and issues such as creep rupture under compressive stress, creep rupture time of notched components, and cyclic creep rupture curves vs. static creep rupture curves are discussed. Difficulties in the calculation of the time fraction term of this method are investigated for notched components and a simplified solution is proposed.
Theory of Box-Type Sandwich Shells With Dissimilar Facings Subjected to Thermomechanical Loads
Authors: Birman Victor , Simitses George J.
Published: January 2022

The present paper outlines a theory of sandwich box-type composite shells designed to withstand a combination of thermal loading, internal pressure, torsional and axial loads. A cross section of the shell represents a rectangular box with curved cylindrical sections at the corners. The facings of the shell are dissimilar to maximize their efficiency, according to the loads acting on each facing. This approach enables a designer to optimize the structure by maximizing the load-carrying capacity or minimizing the weight. The formulation includes the following developments:

1. Global theory of a sandwich shell composed of rectangular and cylindrical sections. Equations of motion are formulated based on a first-order shear deformable version of Sanders’ shell theory.

2. Theory for local deformations and stresses in the facings. The facing is treated as a thin geometrically nonlinear plate or shell on an elastic foundation using von Karman’s approach. The elastic foundation represents a support provided by the opposite facing.

3. An outline of an enhanced micromechanical constitutive formulation based on the incorporation of the effect of the thermomechanical coupling on the material properties and temperature.