Determination of the Structural Elasticity of Human Fingernails by Bending Test and Comparison With the Structural Elasticity of Human Hair

2019 ◽  
Vol 2 (3) ◽  
Author(s):  
Hironori Tohmyoh ◽  
Daiki Taniguchi
Keyword(s):  
Flexural Rigidity ◽  
Beam Theory ◽  
Bending Test ◽  
Test Scheme ◽  
Curved Beam ◽  
Bending Tests ◽  
Nail Polish ◽  
Multilayered Material ◽  
Human Nails

A bending test scheme for accurately determining the structural elasticity of human nails is reported. The structural elasticity expresses the deformability of a multilayered material for bending, and it is the flexural rigidity without depending on the external dimensions. The human nail samples used in this study were prepared from the free ends of the nails and are, therefore, curved, so the equation to determine the structural elasticity was derived from elastic, curved beam theory. The structural elasticity of the nail samples determined by the bending tests was found to be 2.19 GPa, and this value decreased by about 50% when nail polish was put on the nails. Lower value of the Young's modulus of the nail polish was found to cause decrease in the structural elasticity of the sample. Moreover, we also measured the structural elasticity of samples of hair prepared from the same person by the bending tests. Surprisingly, the structural elasticity of the hair (4.37 GPa) was found to be twice that of the nails.

Determination of transverse flexural and shear moduli of chopped carbon fiber tape-reinforced thermoplastic by vibration

2017 ◽  
Vol 52 (3) ◽  
pp. 395-404
Author(s):  
Xiuqi Lyu ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Isamu Ohsawa
Keyword(s):  
Carbon Fiber ◽  
Beam Theory ◽  
Transversely Isotropic ◽  
High Volume ◽  
Bending Test ◽  
Thermoplastic Material ◽  
Shear Moduli ◽  
High Volume Production ◽  
Volume Production

Chopped carbon fiber tape-reinforced thermoplastic material is specifically developed for the high-volume production of lightweight automobiles. With excellent design processability and flexibility, the carbon fiber tape-reinforced thermoplastic material is manufactured by compressing large amounts of randomly oriented, pre-impregnated unidirectional tapes in a plane. Therefore, the carbon fiber tape-reinforced thermoplastic material presents transversely isotropic properties. Transverse shear effect along the thickness direction of carbon fiber tape-reinforced thermoplastic beam has a distinct influence on its flexural deformation. Accordingly, the Timoshenko beam theory combined with vibration frequencies was proposed to determine the set of transverse flexural and shear moduli. Meanwhile, the transverse flexural and shear moduli of carbon fiber tape-reinforced thermoplastic beam were finally determined by fitting all the first seven measured and calculated eigenfrequencies with the least squares criterion. In addition, the suggested thickness to length ratio for the 3-point bending test and Euler–Bernoulli model was given.

Relationship between Bending Modulus and Test Sizes of Laminated Glass/Polyester Composites

2007 ◽  
Vol 537-538 ◽  
pp. 71-79 ◽  
Author(s):  
Z.L. Simon ◽  
László Mihály Vas
Keyword(s):  
Beam Theory ◽  
Measured Data ◽  
Bending Test ◽  
Laminated Glass ◽  
Bending Tests ◽  
Bending Modulus ◽  
Glass Fiber Reinforced ◽  
Best Fitting ◽  
Polyester Composites ◽  
Woven Glass Fiber

The effect of span-to-thickness ratio (L/h) on the bending modulus was investigated in warp, 45°, 67.5° and weft directions in woven glass fiber reinforced polyester laminates. Using classical beam theory the results of the bending tests carried out for L/h = 5,..,50 were extended to the total range of definition (0≤L/h<∞) by applying rational fractional and exponential fractional functions. The extensions take the asymptotic behavior of the bending test for L/h = 0 and L/h = ∞ in account while providing the best fitting to the measured data. It has been shown that the exponential fractional estimations give better results regarding the form of functions that is independent from the directions.

Failure mechanisms in three and four point short beam bending tests of unidirectional glass/epoxy

1992 ◽  
Vol 27 (4) ◽  
pp. 235-243 ◽  
Author(s):  
W C Cui ◽  
M R Wisnom ◽  
M Jones
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Shear Failure ◽  
Beam Theory ◽  
Interlaminar Shear Strength ◽  
Bending Test ◽  
Bending Tests ◽  
Four Point Bending ◽  
Short Beam ◽  
Interlaminar Shear

Three and four point bending tests are compared both analytically and experimentally. In all the three point bending tests, damage was observed under the loading roller in addition to the interlaminar shear failure, while in the four point bending tests, only interlaminar shear failure was observed. Therefore, this four point bending test is valid for measuring the interlaminar shear strength. From the finite element analysis, it is found that the roller diameter is a critical parameter in determining the stress concentrations in short beam tests. In order to avoid damage under the roller and thus to make the short beam test a valid means for measuring the interlaminar shear strength, the appropriate roller diameters should be chosen. The damage under the loading roller in the three point bending test basically reduces the effective specimen thickness and thus this test underestimates the interlaminar shear strength. The interlaminar shear cracks in the short beam tests were found to be randomly distributed in a region between 30 percent and 70 percent through the thickness from the top surface. This is due to the non-linear shear response which means that the shear stress distribution is more uniform near the middle of the section. Also the maximum value of the shear stress is lower than the maximum value given by beam theory. A non-linear shear correction factor is suggested to account for this effect and for the glass/epoxy composite tested here, the actual interlaminar shear strength is only about 83 percent of the apparent value from classical beam theory. The interlaminar shear crack does not occur at the location of maximum shear stress. This may be because there is insufficient energy to propagate a crack at this location.

scholarly journals Deformation of rotating two-layer curved composite beams

2019 ◽  
Vol 6 (1) ◽  
pp. 181-191
Author(s):  
István Ecsedi ◽  
Ákos József Lengyel
Keyword(s):  
Analytical Solution ◽  
Plane Deformation ◽  
Symmetry Plane ◽  
Beam Theory ◽  
Composite Beams ◽  
Curved Beam ◽  
Axis Of Rotation ◽  
Layer Composite ◽  
Euler Bernoulli Beam

AbstractAn analytical solution is presented for the determination of the deformation of rotating two-layer composite beams. The direction of axis of rotation is vertical and the speed of rotation is constant. The axis of rotation is in the plane of symmetry of curved beam. The source of the in-plane deformation is the stationary rotation of the curved beam. The plane of the curvature is the symmetry plane of the curved beam for its material, geometrical and supporting properties. Assumed form of the displacement field meets the prescriptions of the classical Euler-Bernoulli beam theory. Examples illustrate the applications of the presented analytical solution.

scholarly journals Deformation of a cantilever curved beam with variable cross section

2021 ◽  
Vol 16 (1) ◽  
pp. 23-36
Author(s):  
István Escedi ◽  
Attila Baksa
Keyword(s):  
Cross Section ◽  
Elastic Beam ◽  
Beam Theory ◽  
Variable Cross Section ◽  
The Other ◽  
Curved Beam ◽  
Variable Cross ◽  
Cross Sectional ◽  
Euler Bernoulli Beam

This paper deals with the determination of the displacements and stresses in a curved cantilever beam. The considered curved beam has circular centerline and the thickness of its cross section depends on the circumferential coordinate. The kinematics of Euler-Bernoulli beam theory are used. The curved elastic beam is fixed at one end and on the other end is subjected to concentrated moment and force; three different loading cases are considered. The paper gives analytical solutions for radial and circumferential displacements and cross-sectional rotation and circumferential stresses. The presented examples can be used as benchmark for the other types of solutions as given in this paper.

An Improved Procedure for the Determination of the Elastic Constants of Component-Lead-Board Assemblies

1991 ◽  
Vol 113 (4) ◽  
pp. 427-430 ◽  
Author(s):  
T. S. Chang ◽  
Edward B. Magrab
Keyword(s):  
Elastic Constants ◽  
Orthotropic Plate ◽  
Torsion Test ◽  
Least Square ◽  
Bending Test ◽  
Beam Model ◽  
Bending Tests ◽  
Three Point Bending ◽  
Least Square Procedure

An improved means of obtaining the elastic constants of component-lead-board assemblages from two three-point bending tests and one four-point torsion test is proposed. The suggested method models the three-point bending test as an orthotropic plate and uses the experimentally obtained bending and torsion results in a standard nonlinear least square procedure to determine the rigidities in the x and y directions and the Poisson’s ratios directly. Numerical simulation of the method indicates that the beam model overestimates the elastic modulii by 4 to 7 percent and the corresponding rigidities by 7 to 13 percent.

Determination of Concrete Cube Strength from Used Samples / Určení Krychelné Pevnosti Betonu U Použitých Zkušebních Trámců

2012 ◽  
Vol 12 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Oldřich Sucharda ◽  
David Mikolášek ◽  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Concrete Beams ◽  
Linear Analysis ◽  
Bending Tests ◽  
Cube Strength ◽  
Non Linear ◽  
Compressive Strength Of Concrete ◽  
Concrete Cube

Abstract This paper deals with the determination of compressive strength of concrete. Cubes, cylinders and re-used test beams were tested. The concrete beams were first subjected to three-point or fourpoint bending tests and then used for determination of the compressive strength of concrete. Some concrete beams were reinforced, while others had no reinforcement. Accuracy of the experiments and calculations was verified in a non-linear analysis.

Determination of Selected Phthalates in Some Commercial Cosmetic Products by HPLC-UV

2020 ◽  
Vol 23 (10) ◽  
pp. 1010-1022
Author(s):  
Emrah Dural
Keyword(s):  
High Performance ◽  
Phthalate Esters ◽  
High Sensitivity ◽  
Hplc Method ◽  
Cosmetic Products ◽  
Limit Of Quantification ◽  
Nail Polish ◽  
Accuracy And Precision ◽  
Butyl Phthalate

Aim and scope: Due to the serious toxicological risks and their widespread use, quantitative determination of phthalates in cosmetic products have importance for public health. The aim of this study was to develop a validated simple, rapid and reliable high-performance liquid chromatography (HPLC) method for the determination of phthalates which are; dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), di(2- ethylhexyl) phthalate (DEHP), in cosmetic products and to investigate these phthalate (PHT) levels in 48 cosmetic products marketing in Sivas, Turkey. Materials and Methods: Separation was achieved by a reverse-phase ACE-5 C18 column (4.6 x 250 mm, 5.0 μm). As the mobile phase, 5 mM KH2PO4 and acetonitrile were used gradiently at 1.5 ml min-1. All PHT esters were detected at 230 nm and the run time was taking 21 minutes. Results: This method showed the high sensitivity value the limit of quantification (LOQ) values for which are below 0.64 μg mL-1 of all phthalates. Method linearity was ≥0.999 (r2). Accuracy and precision values of all phthalates were calculated between (-6.5) and 6.6 (RE%) and ≤6.2 (RSD%), respectively. Average recovery was between 94.8% and 99.6%. Forty-eight samples used for both babies and adults were successfully analyzed by the developed method. Results have shown that, DMP (340.7 μg mL-1 ±323.7), DEP (1852.1 μg mL-1 ± 2192.0), and DBP (691.3 μg mL-1 ± 1378.5) were used highly in nail polish, fragrance and cream products, respectively. Conclusion: Phthalate esters, which are mostly detected in the content of fragrance, cream and nail polish products and our research in general, are DEP (1852.1 μg mL-1 ± 2192.0), DBP (691.3 μg mL-1 ± 1378.5) and DMP (340.7 μg mL-1 ±323.7), respectively. Phthalates were found in the content of all 48 cosmetic products examined, and the most detected phthalates in general average were DEP (581.7 μg mL-1 + 1405.2) with a rate of 79.2%. The unexpectedly high phthalate content in the examined cosmetic products revealed a great risk of these products on human health. The developed method is a simple, sensitive, reliable and economical alternative for the determination of phthalates in the content of cosmetic products, it can be used to identify phthalate esters in different products after some modifications.

Effects of Delta - Ferrite Content on the Integrity of Reactor Vessel Cladding

2010 ◽  
Author(s):  
Ho-Sang Shin ◽  
Jin-Ki Hong ◽  
Koo-Kab Chung ◽  
Hae-Dong Chung ◽  
Gwang-Yil Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Reactor Vessel ◽  
Bending Test ◽  
Ferrite Content ◽  
Delta Ferrite ◽  
Bending Tests ◽  
Asme Code ◽  
Two Phases ◽  
Scanning Electron

As the design life of new nuclear power plant increases, the austenitic stainless cladding integrity of reactor vessel becomes one of the new concerns. Since 1970’s, there have been some specific recommendations on delta ferrite content of austenitic cladding of reactor vessels and welds. It has been known that the delta ferrite is beneficial for reducing micro-fissure in welds, though the high delta ferrite content increases the probability of embrittlment of welds. In this study, the mechanical and microstructural properties of austenitic weld metals with the limit values of the recommended range (5 ∼ 18 FN) of the delta ferrite control on low alloy steels were characterized by using bending test and scanning electron microscopy. The base metal was ASME Code Sec. II specification SA 508 Gr. 3 Cl. 1 plate and weld materials were EQ308L and EQ309L strips. Four kinds of cladding were deposited with submerged arc welding process on SA508 cl.3 plates. The bending tests were performed through ASME code Sec. IX and the microstructure of fractured surfaces was analyzed by scanning electron microscopy (SEM). In bending tests, there were no fractures except the highest delta ferrite content specimens (28FN). From the SEM observation of fractured surfaces, cracks initiated from the interface between austenite and ferrites phases in the cladding layer and propagated through the continuous interfaces between two phases. For specimens without continuous interfaces of two phases, though the cracks were observed in the interface of phases, the propagation of cracks was not observed. From the test results, continuous interfaces between austenite matrix and ferrite phase provide the path for crack propagation. And the delta ferrite content affects the integrity of cladding of reactor vessel.

A Synthesis of Aluminum Crewboat Structural Design

1982 ◽  
Vol 19 (01) ◽  
pp. 52-72
Author(s):  
William A. Henrickson ◽  
John S. Spencer
Keyword(s):  
Structural Design ◽  
Beam Theory ◽  
Coast Guard ◽  
Observation Data ◽  
Plate Girders ◽  
Worked Example ◽  
Theory Versus ◽  
Grillage Analysis ◽  
Design Stress

The need exists for a simplified structural review guide to enable U.S. Coast Guard marine inspectors to verify the structural adequacy of aluminum crewboats. The authors have developed such a guide. Typical existing crewboat forms and service speeds have been used to reduce the determination of impact pressures to a function of length and displacement. A design stress limit for the cyclic loading of the bottom structure has been determined based on wave observation data. Plating design has been verified by a comparison of sizing by beam theory versus elastoplastic analysis. A simplified grillage analysis has been used to determine the level of support provided by longitudinal plate girders or keelsons. A worked example and tables of section moduli for typical extrusions attached to plating are included as appendices.

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