Design and Performance of Hand-Struck Tools Using High Performance Polymers

2003 ◽  
Author(s):  
J. L. Glancey ◽  
P. Popper ◽  
T. Nasr ◽  
P. Truitt ◽  
M. Orgovan ◽  
...  
Keyword(s):  
High Performance ◽  
Field Tests ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Force Transmission ◽  
Transmission Characteristics ◽  
High Performance Polymers ◽  
Lumped Parameter ◽  
And Performance

One of the oldest tools in the world, the hand-struck chisel, has been improved with the addition of a polymer cap. The cap enhances the safety and ergonomic features without compromising chisel cutting performance. During the development of this new design, a lumped-parameter model was used to quantify force transmission characteristics, and select a suitable polymer-reinforced nylon (Minlon™). In addition, a finite element model together with laboratory and field tests were used to demonstrate that the addition of the polymer cap significantly reduces chisel vibration and noise. Additional long term tests confirmed the cutting effectiveness and durability of the capped chisel.

scholarly journals Evaluation of a Cold-Mixed High-Performance Polyurethane Mixture

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Sun Min ◽  
Yufeng Bi ◽  
Mulian Zheng ◽  
Sai Chen ◽  
Jingjing Li
Keyword(s):  
Energy Consumption ◽  
High Performance ◽  
Greenhouse Gas Emission ◽  
Asphalt Mixture ◽  
Temperature Stability ◽  
Water Stability ◽  
High Temperature Stability ◽  
Forming Mechanism ◽  
And Performance

The energy consumption and greenhouse gas emission of asphalt pavement have become a very serious global problem. The high-temperature stability and durability of polyurethane (PU) are very good. It is studied as an alternative binder for asphalt recently. However, the strength-forming mechanism and the mixture structure of the PU mixture are different from the asphalt mixture. This work explored the design and performance evaluation of the PU mixture. The PU content of mixtures was determined by the creep slope (K), tensile strength ratios (TSR), immersion Cantabro loss (ICL), and the volume of air voids (VV) to ensure better water stability. The high- and low-temperature stability, water stability, dynamic mechanical property, and sustainability of the PU mixture were evaluated and compared with those of the stone matrix asphalt mixture (SMA). The test results showed that the dynamic stability and bending strain of the PU mixture were about 7.5 and 2.3 times of SMA. The adhesion level of PU and the basalt aggregate was one level greater than the limestone, and basalt aggregates were proposed to use in the PU mixture to improve water stability. Although the initial TSR and ICL of PU mixture were lower, the long-term values were higher; the PUM had better long-term water damage resistance. The dynamic modulus and phase angles (φ) of the PU mixture were much higher. The energy consumption and CO2 emission of the PU mixture were lower than those of SMA. Therefore, the cold-mixed PU mixture is a sustainable material with excellent performance and can be used as a substitute for asphalt mixture.

Nondestructive Evaluation of Parts With Degenerate Modes Using Pseudorepeated Roots

2004 ◽  
Vol 126 (3) ◽  
pp. 498-508 ◽  
Author(s):  
Brandon J. Jellison ◽  
Harold R. Kess ◽  
Douglas E. Adams ◽  
David C. Nelson
Keyword(s):  
Raw Materials ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Mass Distributions ◽  
Lumped Parameter ◽  
Fabrication Procedure ◽  
Modes Of Vibration ◽  
Systemic Problems ◽  
Vibration Tests ◽  
Degenerate Modes

The modes of vibration of manufactured parts can be good indicators of the overall quality of the manufacturing process. That is, deviations in the modal frequencies or modal vectors of mechanical parts can help to identify outlier or systemic problems in the raw materials or fabrication procedure. A novel method for characterizing nonuniformities in homogeneous symmetric parts using pseudorepeated modal frequencies is discussed in this paper. It is demonstrated that the spacing between pseudorepeated roots in dominantly symmetric manufactured parts is a direct indicator of nonuniformities (i.e., inclusions, voids) in the stiffness or mass distributions. Smaller differences between split-peaks indicate less nonuniformity, and hence, higher quality parts. A simple fourth-order lumped parameter model is used to elaborate on this technique analytically, a representative finite element model is used to further this development, root locus techniques are used to study the sensitivity to nonuniformities, and acceleration response data from impact vibration tests on deep drawn hemispherical shells are used to verify the approach experimentally.

scholarly journals The Development of a Tympanic Membrane Model and Probabilistic Dose-Response Risk Assessment of Rupture Because of Blast

2020 ◽  
Vol 185 (Supplement_1) ◽  
pp. 234-242
Author(s):  
Anthony E Iyoho ◽  
Kevin Ho ◽  
Philemon Chan
Keyword(s):  
Tympanic Membrane ◽  
Dose Response ◽  
Injury Risk ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Unintended Effects ◽  
Response Curves ◽  
Membrane Rupture ◽  
Lumped Parameter ◽  
Dose Response Curves

ABSTRACT Introduction There is no dose-response model available for the assessment of the risk of tympanic membrane rupture (TMR), commonly known as eardrum rupture, from exposures to blast from nonlethal flashbangs, which can occur concurrently with temporary threshold shift. Therefore, the objective of this work was to develop a fast-running, lumped parameter model of the tympanic membrane (TM) with probabilistic dose-dependent prediction of injury risk. Materials and Methods The lumped parameter model was first benchmarked with a finite element model of the middle ear. To develop the dose-response curves, TMR data from a historic cadaver study were utilized. From these data, the binary probability response was constructed and logistic regression was applied to generate the respective dose-response curves at moderate and severe eardrum rupture severity. Results Hosmer-Lemeshow statistical and receiver operation characteristic analyses showed that maximum stored TM energy was the overall best dose metric or injury correlate when compared with total work and peak TM pressure. Conclusions Dose-response curves are needed for probabilistic risk assessments of unintended effects like TMR. For increased functionality, the lumped parameter model was packaged as a software library that predicts eardrum rupture for a given blast loading condition.

Non-linear dynamic simulation of mechanical periodicity of end-diastolic volume of left ventricle under the influence of baroreflex

2006 ◽  
Vol 220 (3) ◽  
pp. 357-366 ◽  
Author(s):  
Q Wang ◽  
S Xu ◽  
D Chen ◽  
M Collins
Keyword(s):  
Left Ventricle ◽  
Vascular System ◽  
Element Model ◽  
Baroreceptor Reflex ◽  
Lumped Parameter Model ◽  
Linear Dynamic ◽  
End Diastolic Volume ◽  
Lumped Parameter ◽  
Non Linear ◽  
Mechanical Periodicity

Mechanical periodicity (MP) of the end-diastolic volume (EDV) of the left ventricle (LV) is closely associated with cardiovascular pathophysiology. On the basis of the Starling's law of the LV and Burattini and Gnudi's four-element model of the vascular system, and considering baroreceptor reflex, a non-linear dynamic lumped-parameter model is proposed. This simulates the MP phenomena of the EDV by solving a series of one-dimensional discrete non-linear dynamic equations. The results demonstrate that excessive deviations of some physiological parameters often induce MP - the unstable phenomena of EDV - and verify that the effects of baroreceptor reflex enhance the ability of the human physiological system to maintain stability.

Design and Performance of an Expressway Constructed Over Peat by Preloading

1972 ◽  
Vol 9 (4) ◽  
pp. 447-466 ◽  
Author(s):  
Laval Samson ◽  
Pierre La Rochelle
Keyword(s):  
Field Tests ◽  
Field Observations ◽  
The North ◽  
Laboratory Investigations ◽  
And Performance ◽  
Remarkable Agreement ◽  
Oedometer Tests ◽  
Compressibility Characteristics ◽  
Made In

This paper presents the complete record of the laboratory investigations and field observations made in conjunction with the construction of expressway embankments built by preloading over a muskeg. The peat deposit, located on the north shore of the Saint-Laurent River, was initially 10–19 ft (3.0–5.8 m) thick and is underlain by sand. Settlements of the highway fills ranging from 5 to 11 ft (1.5 to 3.3 m) were measured during construction.Laboratory and field tests were performed before and during construction. Field vane tests made at the end of the preloading stage indicated a considerable gain in the shear strength as a result of consolidation. Compressibility characteristics of the peat measured in the laboratory are compared with the field behavior.Periodical field level observations were taken during the 4 years after the removal of the temporary surcharge and have shown that the highway embankments heaved 2–3 in. (5.0–7.5 cm) over a period of 12 months at a gradually decreasing rate. The rebound was followed by long-term secondary settlements totaling 0.5–1.5 in. (1.3–3.8 cm) over the following 3 years of observations. Analysis of the settlement records shows that preloading has been beneficial in reducing the coefficient of secondary compression of the peat. Preloading was simulated in the laboratory by means of oedometer tests on peat samples; both the laboratory results and the field observations revealed a remarkable agreement between the duration of the surcharge stage and the time for rebound to be complete after removal of the surcharge.

scholarly journals Analysis of Fly Fishing Rod Casting Dynamics

2011 ◽  
Vol 18 (6) ◽  
pp. 839-855
Author(s):  
Gang Wang ◽  
Norman Wereley
Keyword(s):  
Finite Element ◽  
Initial Boundary ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Lumped Parameter Model ◽  
Parameter Method ◽  
Line System ◽  
Fly Fishing ◽  
Lumped Parameter ◽  
Rigid Rod

An analysis of fly fishing rod casting dynamics was developed comprising of a nonlinear finite element representation of the composite fly rod and a lumped parameter model for the fly line. A nonlinear finite element model was used to analyze the transient response of the fly rod, in which fly rod responses were simulated for a forward casting stroke. The lumped parameter method was used to discretize the fly line system. Fly line motions were simulated during a cast based on fly rod tip response, which was used as the initial boundary condition for the fly line. Fly line loop generation, propagation, and line turn-over were simulated numerically. Flexible rod results were compared to the rigid rod case, in which the fly tip path was prescribed by a given fly rod butt input. Our numerical results strongly suggest that nonlinear flexibility effects on the fly rod must be included in order to accurately simulate casting dynamics and associated fly line motion.

scholarly journals High performance leadership in unusually challenging educational circumstances

2015 ◽  
Vol 3 (1) ◽  
pp. 28-49 ◽  
Author(s):  
Andy Hargreaves ◽  
Alma Harris
Keyword(s):  
High Performance ◽  
Educational Achievement ◽  
Limited Resources ◽  
Short Term ◽  
Past Performance ◽  
High Performing ◽  
The Face ◽  
Oecd Pisa ◽  
And Performance

This paper draws on findings from the results of a study of leadership in high performing organizations in three sectors. Organizations were sampled and included on the basis of high performance in relation to no performance, past performance, performance among similar peers and performance in the face of limited resources or challenging circumstances. The paper concentrates on leadership in four schools that met the sample criteria.  It draws connections to explanations of the high performance ofEstoniaon the OECD PISA tests of educational achievement. The article argues that leadership in these four schools that performed above expectations comprised more than a set of competencies. Instead, leadership took the form of a narrative or quest that pursued an inspiring dream with relentless determination; took improvement pathways that were more innovative than comparable peers; built collaboration and community including with competing schools; and connected short-term success to long-term sustainability.

The Mechanism on Prediction of Transient Maximum Amplitude for Tuned and Mistuned Blisks

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Luohui Ouyang ◽  
Hai Shang ◽  
Hua Chen ◽  
Qingzhen Bi ◽  
Li-Min Zhu
Keyword(s):  
Damping Ratio ◽  
Maximum Amplitude ◽  
Element Model ◽  
Forced Response ◽  
Lumped Parameter Model ◽  
Fundamental Parameter ◽  
Reduced Order ◽  
Lumped Parameter ◽  
Engine Order ◽  
Acceleration And Deceleration

Abstract Blisks are subjected to frequent acceleration and deceleration, which leads to a transient forced response; however, there is limited understanding of this response. In this work, the mechanism on prediction of transient maximum amplitude is found. An analytical link is proposed between the transient maximum amplitude and a fundamental dimensionless parameter which combines the damping ratio, natural frequency, acceleration, and engine order of the system to reveal the mechanism of the transient maximum amplitude. Therefore, the transient maximum amplitudes of tuned and mistuned blisks are predicted analytically. First, a lumped parameter model is used to study the mechanism of the transient maximum amplitude for a tuned blisk, and an approximated analytical expression is derived between the fundamental parameter and the transient amplification factor of a 1DOF (degree-of-freedom) model. The relationship is also applicable to a reduced order, tuned finite element model (FEM). Second, the mechanism of the transient response for a mistuned blisk is studied in the decoupled modal space of the blisk, based on the 1DOF transient relationship. The transient maximum amplitude in a reduced order, mistuned FEM is predicted. Two lumped parameter models and a FEM are employed to validate the prediction.

scholarly journals Characterization of Giant Magnetostrictive Materials Using Three Complex Material Parameters by Particle Swarm Optimization

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1416
Author(s):  
Yukai Chen ◽  
Xin Yang ◽  
Mingzhi Yang ◽  
Yanfei Wei ◽  
Haobin Zheng
Keyword(s):  
Classical Method ◽  
Lumped Parameter Model ◽  
Complex Material ◽  
Material Parameters ◽  
Magnetostrictive Materials ◽  
Lumped Parameter ◽  
Giant Magnetostrictive Materials ◽  
Power Transducer ◽  
And Performance ◽  
The Stability

Complex material parameters that can represent the losses of giant magnetostrictive materials (GMMs) are the key parameters for high-power transducer design and performance analysis. Since the GMMs work under pre-stress conditions and their performance is highly sensitive to pre-stress, the complex parameters of a GMM are preferably characterized in a specific pre-stress condition. In this study, an optimized characterization method for GMMs is proposed using three complex material parameters. Firstly, a lumped parameter model is improved for a longitudinal transducer by incorporating three material losses. Then, the structural damping and contact damping are experimentally measured and applied to confine the parametric variance ranges. Using the improved lumped parameter model, the real parts of the three key material parameters are characterized by fitting the experimental impedance data while the imaginary parts are separately extracted by the phase data. The global sensitivity analysis that accounts for the interaction effects of the multiple parameter variances shows that the proposed method outperforms the classical method as the sensitivities of all the six key parameters to both impedance and phase fitness functions are all high, which implies that the extracted material complex parameters are credible. In addition, the stability and credibility of the proposed parameter characterization is further corroborated by the results of ten random characterizations.

Can high rates of passive volcanic gas emissions induce reservoir depressurization at Ambrym volcano (Vanuatu)?

2021 ◽  
Author(s):  
Tara Shreve ◽  
Raphaël Grandin ◽  
Marie Boichu
Keyword(s):  
Ground Deformation ◽  
Lumped Parameter Model ◽  
Magma Ascent ◽  
Large Reservoir ◽  
Gas Emissions ◽  
Volcanic System ◽  
Lumped Parameter ◽  
Gas Geochemistry ◽  
The Impact

<p>Satellite-based UV spectrometers can constrain sulphur dioxide (SO<sub>2</sub>) fluxes at passively degassing volcanoes over decadal time scales. From 2005 to 2015, more than 15 volcanoes had mean passive SO<sub>2 </sub>fluxes greater than 1 kiloton per day. Although the processes responsible for such high emission rates are not clearly established, this study aims to investigate the impact of strong degassing on the pressurization state of volcanic systems and the resulting ground deformation. One possible result of high degassing rates is the depressurization of the region where the melt releasing gas is stored, which may result in subsidence at the Earth’s surface. Passive degassing may depressurize pathways between deep and shallow magma storage regions, resulting in magma ascent and possibly eruption.</p><p>A lumped-parameter model developed by Girona et al., 2014 couples the mass loss by passive degassing with reservoir depressurization in an open volcanic system. However, this model has yet to be tested using real measurements of gas emissions and ground deformation. In our study, we focus on Ambrym volcano, the past decade’s top passive emitter of volcanic SO<sub>2</sub>, which exhibits intriguing long-term subsidence patterns and no obvious pressurization preceding eruptive periods. We compare subsidence rates measured by InSAR to the system’s average daily SO<sub>2</sub> flux, focusing on a subsidence episode spanning 2015 to 2017 that is not clearly linked to magma removal from the system. Using realistic input parameters for Ambrym’s system constrained by petrology and gas geochemistry, a range of reservoir volumes and conduit radii are explored. Large reservoir volumes (greater than 30 km<sup>3</sup>) and large conduit radii (greater than 300 m) are consistent with depressurization rates obtained from geodetic modelling of InSAR measurements using the Boundary Element method. By comparing these values of reservoir volume and conduit radius with those estimated from geodesy, gas geochemistry, and seismology, we test the applicability and discuss uncertainties of the aforementioned lumped-parameter physical model to interpret the long-term subsidence at Ambrym volcano as a result of sustained passive degassing.</p>

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