Shock Isolation in Finite-Length Dimer Chains With Linear, Cubic and Hertzian Spring Interactions

2013 ◽  
Author(s):  
Eric Smith ◽  
Al Ferri
Keyword(s):  
Numerical Simulations ◽  
Numerical Investigation ◽  
Finite Length ◽  
Hertzian Contact ◽  
Mass Ratio ◽  
Transmitted Force ◽  
Mass Ratios ◽  
Shock Isolation ◽  
Isolation Systems

A numerical investigation to mitigate the effects of shock in finite 1:1 dimer chains is performed. Dimer chains consist of alternating light and heavy masses. Changing the mass ratio has provided interesting results in previous research. In particular, in the case of Hertzian contacts with zero-preload, certain mass ratios have revealed minimal levels of transmitted force. This paper examines this phenomena from the perspective of utilizing it in practical isolation systems. The zero-preload Hertzian contact case is contrasted with chains connected by linear or cubic springs. Through numerical simulations, tradeoffs are examined between displacement and transmitted force.

Shock Isolation in Finite-Length Dimer Chains With Linear, Cubic, and Hertzian Spring Interactions

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Eric Smith ◽  
Aldo Ferri
Keyword(s):  
Numerical Simulations ◽  
Finite Length ◽  
Hertzian Contact ◽  
Mass Ratio ◽  
Transmitted Force ◽  
Parametric Studies ◽  
Shock Isolation ◽  
Isolation Systems ◽  
Chain Lengths ◽  
Isolation Performance

This paper investigates the use of finite 1:1 dimer chains to mitigate the transmission of shock disturbances. Dimer chains consist of alternating light and heavy masses with interconnecting compliance. Changing the mass ratio has provided interesting results in previous research. In particular, in the case of Hertzian contacts with zero-preload, certain mass ratios have revealed minimal levels of transmitted force. This paper examines this phenomenon from the perspective of utilizing it in practical isolation systems. The zero-preload Hertzian contact case is contrasted with chains connected by linear or cubic springs. Through numerical simulations, tradeoffs are examined between displacement and transmitted force. Parametric studies are conducted to examine how isolation performance changes with mass ratio, stiffness, and different chain lengths.

scholarly journals Two Contact Binaries with Mass Ratios Close to the Minimum Mass Ratio

2021 ◽  
Vol 922 (2) ◽  
pp. 122
Author(s):  
Kai Li ◽  
Qi-Qi Xia ◽  
Chun-Hwey Kim ◽  
Shao-Ming Hu ◽  
Di-Fu Guo ◽  
...  
Keyword(s):  
Gyration Radius ◽  
Mass Ratio ◽  
Mass Ratios ◽  
Contact Binaries ◽  
Contact Binary ◽  
Low Mass ◽  
Ratio Limit ◽  
Low Mass Ratio ◽  
Diagram Analysis

Abstract The cutoff mass ratio is under debate for contact binaries. In this paper, we present the investigation of two contact binaries with mass ratios close to the low mass ratio limit. It is found that the mass ratios of VSX J082700.8+462850 (hereafter J082700) and 1SWASP J132829.37+555246.1 (hereafter J132829) are both less than 0.1 (q ∼ 0.055 for J082700 and q ∼ 0.089 for J132829). J082700 is a shallow contact binary with a contact degree of ∼19%, and J132829 is a deep contact system with a fill-out factor of ∼70%. The O − C diagram analysis indicated that the two systems manifested long-term period decreases. In addition, J082700 exhibits a cyclic modulation which is more likely resulting from the Applegate mechanism. In order to explore the properties of extremely low mass ratio contact binaries (ELMRCBs), we carried out a statistical analysis on contact binaries with mass ratios of q ≲ 0.1 and discovered that the values of J spin/J orb of three systems are greater than 1/3. Two possible explanations can interpret this phenomenon. One explanation is that some physical processes, unknown to date, are not considered when Hut presented the dynamic stability criterion. The other explanation is that the dimensionless gyration radius (k) should be smaller than the value we used (k 2 = 0.06). We also found that the formation of ELMRCBs possibly has two channels. The study of evolutionary states of ELMRCBs reveals that their evolutionary states are similar with those of normal W UMa contact binaries.

Vibration Isolation From Harmonic Disturbances Through Use of Internally Rotating Masses

2015 ◽  
Author(s):  
Eric Smith ◽  
Al Ferri
Keyword(s):  
Kinetic Energy ◽  
Vibration Isolation ◽  
Harmonic Excitation ◽  
Impulsive Loading ◽  
Qualitative Behavior ◽  
Single Degree Of Freedom ◽  
Transmitted Force ◽  
A Chain ◽  
Isolation Systems ◽  
Parameter Values

This paper considers the use of a chain of translating carts or housings having internally rotating eccentric masses in order to accomplish vibration isolation. First a single degree-of-freedom system is harmonically excited to uncover the qualitative behavior of each rotating mass. The simple model is then expanded into a chain of housings, containing rotating eccentric masses, which are interconnected with springs. The internal rotating eccentric masses are damped along their circular pathway by means of linear viscous damping. Due to the lack of elastic or gravitational constraint on the rotating eccentric masses, they provide a nonlinear inertial coupling to their housings. Previous research has shown that such systems are capable of reducing shock or impulsive loading by converting some of the translational kinetic energy into rotational kinetic energy of the internal masses. This paper examines the potential for vibration isolation of a chain of such systems subjected to persistent, harmonic excitation. It is seen that the dynamics of these systems is very complicated, but that trends are observed which have implications for practical isolation systems. Using simulation studies, tradeoffs are examined between displacement and transmitted force for a range of physical parameter values.

scholarly journals Charge-to-mass ratio of individual blowing-snow particles

1998 ◽  
Vol 26 ◽  
pp. 207-211 ◽  
Author(s):  
D. S. Schmidt ◽  
J. D. Dent ◽  
R. A. Schmidt
Keyword(s):  
Negative Charge ◽  
Electrostatic Force ◽  
Average Charge ◽  
Blowing Snow ◽  
Mass Ratio ◽  
Mass Ratios ◽  
Snow Storm ◽  
Individual Particles ◽  
Large Charge ◽  
Snow Samples

Determining the electrostatic force acting on saltating snow particles requires knowledge of the electric field in the saltation region and the charge on the particle. To date, measurements of average charge-to-mass ratios for blowing-snow samples have been made but Schmidt and Schmidt (1993) have indicated these may underestimate charge-to-mass ratios for individual particles due to a mixture of positive and negative charge in the samples. This paper reports on measurements of charge-to-mass ratio for individual blowing-snow particles during a moderate blowing-snow storm in southwestern Wyoming. We measured charge-to-mass ratios as large as -208μC,kg-1, significantly higher than the -10μC kg-1measured by Latham and Montagne (1970) and -50μCkg-1measured by Wishart (1970). This large charge-to-mass ratio was accompanied by a distribution of positive and negative charge on the particles, supporting the conclusions of Schmidt and Schmidt (1993).

A New Fabrication Process for Microstructures With High Area-to-Mass Ratios by Stiffness Enhancement

2018 ◽  
Author(s):  
Zhongjing Ren ◽  
Jianping Yuan ◽  
Xiaoyu Su ◽  
Hao Sun ◽  
Richard Galos ◽  
...  
Keyword(s):  
Joule Heating ◽  
Mechanical Systems ◽  
Silicon Layer ◽  
Fabrication Process ◽  
Structural Parameter ◽  
Mass Ratio ◽  
Micro Electro Mechanical Systems ◽  
Thickness Increase ◽  
High Area ◽  
Mass Ratios

A new fabrication process for stiffness-enhanced microstructures with high area-to-mass ratios is presented in this paper. In order to acquire an enhanced stiffness without ruining the structural parameter of area-to-mass ratio, multilayered metallic microstructures are proposed and fabricated by surface and bulk fabrication processes from Micro-Electro-Mechanical Systems (MEMS) technologies. Microstructures based on beams with symmetrically deposited metals are physically built and tested on wafers. A sacrificial silicon layer is used to form gaps between bimetal layers and the microstructures can be deployed vertically when heated due to the effect of thermal mismatch between different materials. The results show a dramatic thickness increase when actuated by Joule heating, and thus a great bending stiffness enhancement.

scholarly journals High Mass Ratio Contact Binaries: Recent Evolution into Contact?

1989 ◽  
Vol 107 ◽  
pp. 348-349
Author(s):  
Bruce J. Hrivnak
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Primary Component ◽  
High Mass ◽  
Mass Ratio ◽  
Origin And Evolution ◽  
Momentum Loss ◽  
Angular Momentum Loss ◽  
Mass Ratios ◽  
Contact Binaries

Recent theories of the origin and evolution of contact binaries suggest that the two stars evolve into contact through angular momentum loss (AML; Mochnacki 1981, Vilhu 1982). When in contact, the system then evolves toward smaller mass ratio through mass transfer from the secondary to the primary component (Webbink 1976, Rahunen and Vilhu 1982). Most contact binaries have mass ratios of 0.3 to 0.5.

scholarly journals Response of spring wheat to NPK and S fertilization. The content and uptake of macronutrients and the value of ionic ratios

2018 ◽  
Vol 16 (1) ◽  
pp. 1059-1065 ◽  
Author(s):  
Hanna Klikocka ◽  
Marek Marks ◽  
Bożena Barczak ◽  
Bogdan Szostak ◽  
Anna Podleśna ◽  
...  
Keyword(s):  
Field Experiment ◽  
Grain Yield ◽  
Spring Wheat ◽  
Positive Response ◽  
Dry Mass ◽  
Mass Ratio ◽  
P Content ◽  
Mass Ratios ◽  
S Application ◽  
S Fertilizers

AbstractThe aim of the study was to evaluate the effect of nitrogen (N) and sulphur (S) fertilizers on the content and uptake of macronutrients by grain dry mass (DM) of spring wheat. A field experiment was conducted in southeastern Poland on Cambisols (WRB 2007), in conditions of low S content in the soil. The experiment included 2 factors: fertilization with N (0, 40, 80, 120 kg ha-1) and with S (0, 50 kg ha-1).The experiment showed a positive response of spring wheat to N and S fertilization. The highest grain yield was found after application of 80 kg N ha-1 and addition of 50 kg S ha-1 (5.43 t ha-1). The described combination resulted in beneficial content of phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca) (P –4.267, K–4.533, Mg–1.567, Ca–0.433 g kg-1) and uptake of macroelements by grain dry mass (DM) (P–20.48, K–21.79, Mg–7.52, Ca–2.08 kg ha-1). A generally positive correlation was found between content and uptake of macronutrients with exception of P content. Fertilization with N caused significantly narrowed mass ratios of K+: Ca2+, K+: Mg2+ and mass and mole ratio of K+:(Ca2++Mg2+) and increased mass ratio of Ca:P. While S application narrowed significantly, mass ratios of K+:Ca2+ and K+: (Ca2+ + Mg2+) and increased mass ratio of Ca:P.

scholarly journals Trojans in Exosystems with Two Massive Planets

2012 ◽  
Vol 8 (S293) ◽  
pp. 152-158 ◽  
Author(s):  
Rudolf Dvorak ◽  
Li-Yong Zhou ◽  
Helmut Baudisch
Keyword(s):  
Numerical Integration ◽  
Equilibrium Points ◽  
Planetary Systems ◽  
Central Star ◽  
Giant Planets ◽  
Dynamical Model ◽  
Outer Planet ◽  
Mass Ratio ◽  
Wide Range ◽  
Mass Ratios

AbstractWe take as dynamical model for extrasolar planetary systems a central star like our Sun and two giant planets m1 and m2 like Jupiter and Saturn. We change the mass ratio μ=m2/m1 of the two large planets for a wide range of 1/16 < μ < 16. We also change the ratio between the initial semi-major axes (ν=a2/a1) in the range of 1.2 < ν < 3 to model the different architecture of extrasolar planetary systems hosting two giant planets. The results for possible Trojans (Trojan planets) in the equilateral equilibrium points of the inner planet m1 and the outer planet m2 were derived with the aid of numerical integration. It turned out that in many configurations – depending on the mass ratios μ and the semi-major axes ratio ν – giant planets may host Trojans.

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