scholarly journals Influence of Material on Wheelchair Vibrations

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 127
Author(s):  
Takeshi Waga ◽  
Soichiro Ura ◽  
Masahito Nagamori ◽  
Hisashi Uchiyama ◽  
Akira Shionoya
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Young’S Modulus ◽  
Vibration Frequency ◽  
Weight Reduction ◽  
Young's Modulus ◽  
Specific Weight ◽  
Wheelchair Sports ◽  
The Difference

Wheelchair sports have a tendency to depend on the performance of wheelchairs, and the weight reduction of wheelchairs made of various alloys has helped improve the performance of players. Some players have mentioned, however, that the operability and riding comfort of competition wheelchair have been affected by changing the wheelchair materials; stiffness and weight are considered to be related to operability and riding comfort. In this experiment, we installed some weights on the center of the mass of a competitive wheelchair made of magnesium alloy to be the same mass of a wheelchair made of aluminum alloy; vibrations that occurred on both wheelchairs while driving were measured and compared. The experiment was performed using 3-axis sensors. This experiment showed that the vibration frequency of the wheelchair made of magnesium alloy was different from that made of aluminum alloy. This result was thought to be influenced by the difference in Young’s modulus or the specific weight.

Transverse Young's Moduli and Cell Shapes in Coniferous Early Wood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Ugai Watanabe ◽  
Minoru Fujita ◽  
Misato Norimoto
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Bending Moment ◽  
Cell Models ◽  
Young’S Moduli ◽  
Cell Shapes ◽  
The Difference ◽  
Square Cells ◽  
Experimental Values ◽  
The Relationship

Summary The relationship between transverse Young's moduli and cell shapes in coniferous early wood was investigated using cell models constructed by two dimensional power spectrum analysis. The calculated values of tangential Young's modulus qualitatively explained the relationship between experimental values and density as well as the difference in experimental values among species. The calculated values of radial Young's modulus for the species having hexagonal cells agreed well with the experimental values, whereas, for the species having square cells, the calculated values were much larger than the experimental values. This result was ascribed to the fact that the bending moment on the radial cell wall of square cell models was calculated to be small. It is suggested that the asymmetrical shape of real wood cells or the behavior of nodes during ell deformation is an important factor in the mechanism of linear elastic deformation of wood cells.

Comparison of results obtained by static 3- and 4-point bending and flexural vibration tests on solid wood, MDF, and 5-plywood

Holzforschung ◽  
2013 ◽  
Vol 67 (8) ◽  
pp. 941-948 ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Medium Density Fiberboard ◽  
Flexural Vibration ◽  
Solid Wood ◽  
Bending Tests ◽  
Four Point Bending ◽  
Flexural Vibration Test ◽  
The Difference ◽  
Vibration Tests

Abstract The flexural Young’s modulus of western hemlock, medium-density fiberboard, and 5-plywood (made of lauan) has been determined by conducting three- and four-point bending tests with various span lengths and by flexural vibration test. The Young’s modulus was significantly influenced by the deflection measurement method. In particular, the Young’s modulus was not reliable based on the difference between the deflections at two specific points in the specimen, although this test is standardized according to ISO 3349-1975 and JIS Z2101-2009.

Measurement of Young’s Modulus and Internal Damping of Pork Muscle in Dynamic Mode

2016 ◽  
Vol 11 (03) ◽  
pp. 109-116
Author(s):  
Moez Chakroun ◽  
Med Hédi Ben Ghozlen
Keyword(s):  
Young’S Modulus ◽  
Vibration Frequency ◽  
Young's Modulus ◽  
Mechanical Impedance ◽  
Lower Surface ◽  
Dynamic Mode ◽  
Internal Damping ◽  
Body Tissues ◽  
Measured Impedance ◽  
Two Parameters

Automotive shocks involve various tiers’ speed for different human body tissues. Knowing the behavior of these tissues, including muscles, in different vibration frequency is therefore necessary. The muscle has viscoelatic properties. Dynamically, this material has variable mechanical properties depending on the vibration frequency. A novel technique is being employed to examine the variation of the mechanical impedance of pork muscle as a function of frequency. A force is imposed on the lower surface of the sample and acceleration is measured on its upper surface. These two parameters are measured using sensors. The sample is modeled by Kelvin–Voigt model. These measures allow deducing the change in the mechanical impedance modulus (/[Formula: see text]/ [Formula: see text] /Force: Acceleration/) of pork muscle as a function of vibration frequency. The measured impedance has a resonance of approximately 60[Formula: see text]Hz. Best-fit parameters of theoretical impedance can be deduced by superposition with the experiment result. The variation of Young’s modulus and internal damping of pig’s muscle as a function of frequency are determined. The results obtained between 5[Formula: see text]Hz and 30[Formula: see text]Hz are the same as determined by Aimedieu and al in 2003, therefore validating our technique. The Young’s modulus of muscle increases with the frequency, on the other hand, we note a rating decrease of internal damping.

scholarly journals Adhesive Joint Stiffness in the Aspect of FEM Modelling

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3911 ◽  
Author(s):  
Anasiewicz ◽  
Kuczmaszewski
Keyword(s):  
Aluminum Alloy ◽  
Numerical Model ◽  
Young’S Modulus ◽  
Adhesive Joint ◽  
Structural Changes ◽  
Young's Modulus ◽  
Joint Stiffness ◽  
Experimental Tests ◽  
Boundary Zone ◽  
Adhesive Properties

The paper presents the results of nanoindentation testing, carried out along the thickness of the adhesive joint joining sheets of aluminum alloy. The purpose of the tests was to determine changes in the Young’s modulus in the joint resulting from the active impact of the joined aluminum alloy sheets on the adhesive during curing of the adhesive bond. Structural changes that take place during curing of the joint, especially in the boundary zone, can have a significant impact on the adhesive properties and consequently, on the adhesive joint strength. The Young’s modulus of the adhesive (Ek) in the joint assumes variable values as the distance from the connections changes. This phenomenon is called the apparent Young’s modulus. The problem is to define the size of the boundary zone in which the value of Ek significantly differs from the value in the so-called core. Based on the obtained results of experimental tests, a numerical model was built taking into account the observed differences in the properties of the joint material. The stress distribution in the adhesive joint, single-lap connection with the three-zone adhesive joint, was analyzed in comparison to the classical numerical model in which adhesive in the adhesive joint is treated as isotropic in terms of rigidity.

High Temperature Mechanical Properties of Ni-YSZ Cermets for SOFC Anode

2010 ◽  
Author(s):  
Fumitada Iguchi ◽  
Hiromichi Kitahara ◽  
Hiroo Yugami
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Flexural Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Strain Diagram ◽  
Thermal Cycles ◽  
High Temperature Mechanical Properties ◽  
Sofc Anode ◽  
The Difference

The mechanical properties of Ni-YSZ cermets at high temperature in reduction atmosphere were evaluated by the four points bending method. We studied the influences of reduction and thermal cycles, i.e. a cycle from R.T. to 800°C, to flexural strength and Young’s modulus. The flexural strength of Ni-YSZ at room temperature was lower than that of NiO-YSZ by about 10 to 20% mainly caused by the increment of porosity. But, the flexural strength of Ni-YSZ at 800°C was drastically decreased by an half of that at R.T. In addition, the stress–strain diagram of Ni-YSZ at 800°C indicated that it showed weak ductility. The maximum observed strain was over 0.5% at 30MPa. On the contrary, NiO-YSZ showed only brittlely at 800°C. The difference was caused by Ni metal in the Ni-YSZ cermets. Therefore, it was expected that Ni-YSZ is easily deformed in operation, though residual stress between an anode and an electrolyte was low. The influence of thermal cycles to flexural strength and Young’s modulus was not observed clearly. At the same time, the differences of microstructure were not observed. Therefore, it was concluded that the cycle does not change mechanical properties significantly.

scholarly journals Optimization of Magnesium Alloy Wheel Dynamic Impact Performance

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Xin Jiang ◽  
Hai Liu ◽  
Rui Lyu ◽  
Yoshio Fukushima ◽  
Naoki Kawada ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Weight Reduction ◽  
Ride Comfort ◽  
Structural Parameters ◽  
Lightweight Design ◽  
Dynamic Impact ◽  
Impact Performance ◽  
Alloy Wheel ◽  
The Impact

Designing lightweight and comfortable automotive vehicles is a primary aim of the industry. Lightweight wheel designs can have a negative effect on the dynamic impact performance of the wheel; therefore, striking a balance between these two factors is a key objective in the design of automotive vehicles. Magnesium alloy wheels were investigated as magnesium alloy has damping performance advantages over some metal materials. Damping test methods were designed to establish the damping performance parameters of the magnesium alloy material. A finite element analysis model of magnesium alloy wheels was established with certain boundary conditions and constraints. The applicability of the model was verified by free modal evaluation of the wheel. Dynamic impact simulation analysis of the designed wheels was carried out, and the dynamic speed responses of magnesium alloy wheels under the impact of a dynamic load on the road surface were obtained. Comparison of the dynamic impact performance of magnesium and aluminum alloy wheels with the same structure showed that the magnesium alloy wheel achieved the target weight reduction of 32.3%; however, the dynamic impact performance was reduced. In order to realize the lightweight design, the dynamic impact performance of the magnesium alloy wheel should not be inferior to that of the aluminum alloy wheel; therefore, the design of the magnesium alloy wheel structure was optimized. The structural design optimization of the magnesium alloy wheel was carried out by defining the structural parameters of the wheel and using the acceleration and shock response of the wheel as the outputs. The optimization of weight reduction and dynamic impact performance of magnesium alloy wheels was achieved. Consequently, the designed magnesium alloy wheel was shown to have improved ride comfort while satisfying wheel structural performance standards and providing lightweight design.

scholarly journals Experiments on the elasticity of the vocal cords

1973 ◽  
Vol 20 (1) ◽  
Author(s):  
P. H. Damsté ◽  
G. H. Wieneke
Keyword(s):  
Vocal Cord ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Vocal Folds ◽  
Vocal Cords ◽  
Male And Female ◽  
Vocal Pitch ◽  
Female Voices ◽  
The Difference ◽  
Limited Accuracy

Regulation of vocal pitch occurs by changes in the length and tension of the vocal folds. Because the Young's modulus of the vocal cord ligament could be a factor which determines the difference between male and female voices, this was made an object of research. No differences could be shown. Some of the problems and the limited accuracy of these experiments are reviewed.

In Situ Measurement of the Young’s Modulus of an Embedded Inclusion by Acoustic Microscopy

1997 ◽  
Vol 119 (2) ◽  
pp. 143-147 ◽  
Author(s):  
S. Canumalla ◽  
G. A. Gordon ◽  
R. N. Pangborn
Keyword(s):  
Aluminum Alloy ◽  
Rayleigh Wave ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Target Material ◽  
Acoustic Microscopy ◽  
Alloy Matrix ◽  
Cross Sectional ◽  
Rayleigh Wave Speed

Alumina-silicate inclusions (shot) have been found to adversely affect the mechanical properties of a short alumina-silicate fiber reinforced aluminum alloy (A356). To better understand the differences between the responses of the shot and fibers to applied loads, the Young’s modulus of the shot is measured and compared to that of the fibers. The Rayleigh wave speed in the shot particle (cross-sectional area of 200 μm × 150 μm), measured in situ to be 4041 m/s using a scanning acoustic microscope, was used to calculate the Young’s modulus of the shot particle (132 GPa). The accuracy of the technique and the experimental arrangement used was verified to be better than four percent by independent measurements of the Rayleigh wave speeds in the aluminum alloy matrix and an embedded sapphire fiber. The fiber modulus was estimated to be 225 GPa based on a comparison of previously measured composite modulus with micromechanical predictions. Thus, shot was found to have a Young’s modulus 40 percent lower than that of the fibers. The applicability of the V(z) technique has been demonstrated for measuring the elastic properties over a microscopic area, even when the target material is an embedded inclusion.

Experimental Research on the Dynamic Young’s Modulus of Specified Density Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 164-167
Author(s):  
Xiao Er Zhou ◽  
Yan Kun Zhang ◽  
De Min Jiang
Keyword(s):  
Young’S Modulus ◽  
Experimental Research ◽  
Vibration Frequency ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Natural Vibration ◽  
Young's Modulus ◽  
Natural Vibration Frequency ◽  
Dynamic Modulus Of Elasticity ◽  
Static Young’S Modulus

From the experimental research, the relations between the dynamic modulus of elasticity and natural vibration frequency of specified density concrete are studied, the static Young’s modulus and dynamic modulus are compared. Based on regression analysis, the influence of different Substitution ratio of lightweight aggregate, age of concrete and cement water ratio is studied. According to the test results, the formula of natural vibration frequency and the dynamic modulus of elasticity of Specified density concrete is given, which provide theory basis for the nondestructive detector of the specified density concrete.

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