scholarly journals A Low-frequency Apparatus for Characterizing the Mechanical Properties of Rocks

2011 ◽  
Author(s):  
V. Mikhaltsevitch ◽  
M. Lebedev ◽  
B. Gurevich
Keyword(s):  
Mechanical Properties ◽  
Low Frequency ◽  
Frequency Apparatus

Sound insulation performance of pyramidal truss core sandwich structure with frame

2021 ◽  
pp. 109963622110288
Author(s):  
Yu-Zhou Wang ◽  
Li Ma
Keyword(s):  
Mechanical Properties ◽  
Sandwich Structure ◽  
Transmission Loss ◽  
Low Frequency ◽  
Sound Insulation ◽  
Geometrical Parameters ◽  
Acoustic Performance ◽  
Truss Core ◽  
Pyramidal Truss ◽  
Wave Angle

Recently, sandwich structures have been widely used in different fields because of their good mechanical properties, but these structures are weak in acoustic performance. In this paper, by combining pyramidal truss core sandwich structure with frame, a new structure is proposed with both good mechanical properties and excellent acoustic performance at low frequency. An analytical model of the pyramidal truss core sandwich structure with frame is developed to investigate the sound transmission loss (STL) performance. Finite element method (FEM) is also used to investigate the STL performance at low frequency. The effects of the incident wave angle and the geometrical parameters on the STL of the structure are discussed.

Lunar rock Q in 3000-5000 range achieved in laboratory

1977 ◽  
Vol 285 (1327) ◽  
pp. 475-479 ◽  
Keyword(s):  
Seismic Data ◽  
Room Temperature ◽  
Low Frequency ◽  
Thin Layers ◽  
Lunar Sample ◽  
Lunar Rock ◽  
Seismic Frequencies ◽  
Different Gases ◽  
Frequency Apparatus

Q measurements carried out by the vibrating bar technique on lunar sample 70215,85 have yielded Q values as high as 4800 at room temperature. The strong outgassing procedures necessary to raise the Q to these high values from Q =- 60 (when received) and studies of the effect on Q by a variety of different gases shows that the removal of thin layers of adsorbed H 2 O are responsible for the dramatic increase in Q . Experiments carried out with a low frequency apparatus on a terrestrial analogue at 50 Hz suggest similar increases in Q with outgassing, thus providing evidence that dramatic effects on Q can be expected to occur down to seismic frequencies. These results, in part, explain the contrast between seismic data in the lunar and terrestrial crust in terms of the absence and presence respectively of adsorbed H 2 O.

Microstructures and Mechanical Properties of AZ31B Extruded Sheets from Different Casting Processing

2007 ◽  
Vol 546-549 ◽  
pp. 399-402
Author(s):  
Qi Chi Le ◽  
Zi Qiang Zhang ◽  
Jian Zhong Cui
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Electromagnetic Field ◽  
Deformation Process ◽  
Low Frequency ◽  
High Quality ◽  
Refined Microstructure ◽  
Plastic Deformation Process ◽  
Dc Casting ◽  
Microstructures And Mechanical Properties

A novel way producing magnesium billets, LFEC (low frequency electromagnetic casting processing), was developed in Northeastern University in China. The high-quality magnesium billets with less macrosegregation, refined microstructure, and better surface quality were achieved because the temperature field and the flow pattern of magnesium DC casting were improved significantly after applying low frequency electromagnetic field. Extrusion is an important plastic deformation process for magnesium alloys. In this research, the magnesium billets from LFEC were extruded through a special designed die into sheets. The results of investigation on AZ31B indicated that the extrusion velocity has obvious effects on their microstructures and mechanical properties and the sheets from LFEC had finer microstructure and higher mechanical properties than that from conventional DC casting.

Mechanical Properties of Tetrazole Polymers

2014 ◽  
Vol 590 ◽  
pp. 19-22
Author(s):  
Rene Alejandro Castro ◽  
Evgeniy N. Lushin
Keyword(s):  
Mechanical Properties ◽  
Viscoelastic Properties ◽  
Mechanical Characteristics ◽  
Low Frequency ◽  
Acoustic Method ◽  
Molecular Organization

Low-frequency acoustic method, studies of viscoelastic properties of polymers tetrazolecontaining. It was shown that the introduction of modifiers KCl and KNO3 has a different effect on the dynamic and mechanical characteristics tetrazolecontaining polymers. It is noted that such changes are related to the restructuring of the molecular organization of cross-linked polymers.

Effect of Fe on microstructures and mechanical properties of an Al–Mg–Si–Cu–Cr–Zr alloy prepared by low frequency electromagnetic casting

2017 ◽  
Vol 32 (11) ◽  
pp. 2067-2078
Author(s):  
Yi Meng ◽  
Jian-zhong Cui ◽  
Zhi-hao Zhao
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Low Frequency ◽  
Hot Extrusion ◽  
Casting Process ◽  
Electromagnetic Casting ◽  
Fe Content ◽  
Microstructures And Mechanical Properties ◽  
Phase Q ◽  
Zr Alloy

The effects of different Fe contents (0.168, 0.356 and 0.601 wt%) on microstructures and mechanical properties of the Al–1.6Mg–1.2Si–1.1Cu–0.15Cr–0.15Zr (all in wt%) alloys prepared by low frequency electromagnetic casting process were investigated in the process of solidification, hot extrusion, solid solution and aging treatments. The results show that the increase of Fe content promotes the formation of feathery grains in the process of solidification and the precipitation of another important strengthening phase Q′ with small size. Additionally, it also results in no recrystallization even after solid solution at a high temperature of 550 °C, which is because of the increase number of elliptical shaped and fine DO22-Al3Zr dispersoids (∼70 nm long and ∼35 nm wide) and the spherical or elliptical shaped Fe-containing phases. When Fe content of the alloy increases to 0.356 wt%, both the ultimate tensile strength and yield strength of the alloy-T6 increase by more than 60 MPa and with little cost of ductility.

Mechanical properties of cellulose-based electro-active paper

2008 ◽  
Vol 222 (4) ◽  
pp. 577-583 ◽  
Author(s):  
J Kim ◽  
W Jung ◽  
C H Jo ◽  
J Shelton ◽  
W Craft
Keyword(s):  
Mechanical Properties ◽  
Low Cost ◽  
Creep Behaviour ◽  
Actuation Voltage ◽  
Low Frequency ◽  
Polymer Materials ◽  
Additional Material ◽  
Elastic And Plastic Deformations ◽  
Field Excitation ◽  
Cyclic Loading Tests

Mechanical properties of cellulose-based electro-active paper (EAPap) are characterized in this work. Cellulose-based EAPap has been studied as a potential actuator concept, as a result of its low actuation voltage, lightweight, low power consumption, biodegradability and low cost. EAPap is made from cellulose paper, coated with thin electrically conducting electrodes. This EAPap shows a reversible and reproducible bending movement as well as a longitudinal displacement under electric field excitation. However, the EAPap is a complex anisotropic material, which has not been extensively characterized. It is important to have extended property data for EAPap so that the actuator performance can be optimized, and this requires additional material testing. Our material test results show that EAPap has two distinct elastic constants. The initial Young's modulus of EAPap is in the range of 4–9 GPa, which is higher than other polymer materials. This modulus is also orientation dependent, which may be associated with the piezoelectricity of the EAPap materials. Another important property is that the dynamically induced mechanical strains of these materials exhibit linear creep behaviour as confirmed by constant stress and low frequency cyclic loading tests. From scanning electron microscope investigations, cellulose EAPap exhibits a layered, anisotropic cellulose macromolecular structure that exhibits both elastic and plastic deformations, as well as substantial temperature and humidity dependence.

scholarly journals Application of Digital Image Correlation to Measurement of Packaging Material Mechanical Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jian-Wei Zhou ◽  
Dong-Hong Liu ◽  
Lan-Yuan Shao ◽  
Zhen-Lin Wang
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Poisson Ratio ◽  
Low Frequency ◽  
Measurement Range ◽  
Image Correlation ◽  
Packaging Materials ◽  
Entire Area ◽  
Low Frequency Vibration

Among various packaging materials, papers and polymer plastics are the most common due to their light weights, low costs, and other advantages. However, their mechanical properties are difficult to measure precisely because of their softness. To overcome the difficulty, a new measure instrument prototype is proposed based on an optical method known as the digital image correlation (DIC). Experiments are designed to apply the DIC to measure mechanical properties of flexible packaging materials, including the stress-strain relationship, the Poisson ratio, the coefficient of heat expansion, the creep deformation, and the top-pressure deformation of corrugated box. In addition, the low frequency vibration of package is simulated, and the vibration frequencies are measured by DIC. Results obtained in the experiments illustrate the advantages of the DIC over traditional methods: noncontact, no reinforced effect, high precision over entire area, wide measurement range, and good measurement stability.

Characteristic Analysis of Prestressed Concrete Frame Joints with Spread-Ended Beams

2014 ◽  
Vol 578-579 ◽  
pp. 648-652
Author(s):  
Qing Wen Liu ◽  
Fu Qiang Wu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Prestressed Concrete ◽  
Outer Region ◽  
Low Frequency ◽  
Core Region ◽  
Seismic Loads ◽  
Characteristic Analysis ◽  
Concrete Frame ◽  
Reversed Loading

Three joints of prestressed concrete frame are studied under low frequency reversed loading. The failure and cracks feature, damage characteristics and mechanical properties under seismic loads are comparatively analysed between joints with spread-ended beams and conventional joints. Studies show that the layout of prestressing tendons and joints with spread-ended beams have little influence on the bearing capacity and ductility. Prestressing tendons through the joint core region can improve the shear strength of joints, but tendons through the joint outer region can not. We need to only consider the influence on the area of prestressing tendons through joint core region when calculating the shear strength of joints.

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