In the calculation, the Young modulus data of Oak red and Pine red, are taken form a reference , which provide a very complete mechanical properties of woods that are growth in America. The Young modulus of wood normally obtained for compression. Woods are natural materials, so that their mechanical properties depend on growth condition such as weather, soil, moisture. The moduli values provided in the reference are average values. The moduli were determined using bending tests: a simply supported, center-loaded beam, on a span depth ratio of 14/1. In the calculation, the values are used without any correction for shear deflection.
Spring back prediction is an important issue for sheet metal forming industry. Most sheet metal elements undergo a complicated cyclical deformation history during the forming process. For an accurate prediction of spring back the young modulus in change effect must be considered to determine accurately the internal stress distribution within the sheet metal deformation. Mathematical modeling of spring back predication has done in this report. There are swift’s model law for elastic region and power rule for modeling is used to estimate predication Keywords —spring back ,swift’s model, isotropic hardening, power rule
We have thus developed a simple theoretical model to study the size and shape dependence of Young modulus and vibrational frequency of nanomaterials. The model predictions are in good agreement with the available experimental data, which validate the proposed model. The beauty of our model is that it requires only one input parameter (h) which is easily available. Our model is applicable for metallic elements as well as compound nanomaterials. Our model explains the increasing and decreasing behavior of Young modulus and vibrational frequency with size. Due to the simplicity and applicability of the model, it may be extended to the other nanomaterials and may be of current interest to the researchers engaged in the study of other nanomaterials.
Studies have shown that SWE can be used to differentiate the malignant from benign thyroid nodules [25, 26]. Varying SWVs have been reported for malignant nodules. Park et al. reported the following the cutoff values for pre- dicting malignancy were: E mean , 85.2 kPa; E max , 94.0 kPa; and E min , 54.0 kPa . Samir et al. reported that the mean Young modulus esti- mate for malignant thyroid nodules was 31.69 kPa (10.97-50.31 kPa), and recommended a cutoff value of 22.30 kPa for diagnosing thyroid malignancy . In our study, tumor stiffness was higher in the PTC group than in the PTMC group, which is consistent with the report that tumor stiffness increases with the size and growth of breast cancers . However, the elastic parameters calculated in our study were lower than those previously reported. This dif- ference is likely attributable to the following reasons: (1) Our study was conducted in nude mice, which show rapid tumor growth as com- pared to human tumors; this may partially account for the lower tumor stiffness in this experiment. (2) None of the tumors in our study had calcifications or inflammation, which are known to increase tissue stiffness . (3) Finally, the tumor lesions in our study protruded from the thigh surface, and the impact force exerted by the probe may have been uneven, resulting in lower elastic parameters.
The compression stress increases the density and de- creases volume due to the shrinkage of orbitals  as shown in Figure 1, and the distance between atoms , which entails an increment in the bond strength  and bulk modulus  (Figure 2) because the bulk modulus depends upon the density directly, and the young modulus which depends upon the bulk modulus , and vice verse for the tensile stress.
The effects of UVA/riboflavin crosslinking treatment on the Young modulus of the collagen hydrogels with a concentration of 3.5 mg/ml are displayed in fig 3. There was an increase in the modulus after UVA/riboflavin treatment that was dependent on the UVA exposure time. The increase in modulus was statistically significant after 15 minutes’ exposure comparable with non-treated samples. In addition, there was a significant difference between the hydrogels exposed for 15, 30 and 45 min but no statistically significant difference after 45 min, as determined using the ANOVA–Tukey test with a 95% confidence interval (Minitab). This suggests that the majority of crosslinking occurred in the first 30–45 min, and a longer exposure time might be unnecessary. Hydrogels with a collagen concentration of both 2.5 mg/ml and 3.5 mg/ml showed an increase in modulus of approximately 240% and 200%, respectively, after UVA exposure for 30 min (fig 4). The increased modulus was maintained over 1 week in culture (fig 5).
Young modulus and breaking force were measured by the random marker method. This method was described in detail by Gładyszewska (2007). The method is based on analysis of the relative position of markers randomly dis- tributed on the surfaces of tested samples. In this method, we determine changes in the position of markers on the sur- face of a sample before and after the action of tensile force. The change in the distance between two arbitrarily chosen points before and after deformation is treated as relative elongation of a linear element arranged at any angle to the direction of the force. The general relationship between the relative elongation of the linear element and the strain tensor allows determination of strain tensor components expressed in the direction of the analyzed linear element. To determine all components of the strain tensor, a neces- sary condition is to know the relative elongation of at least three linear elements not lying on a straight line. The strain tensor obtained is not expressed in the direction of the main axis. The relationship between the strain tensor compo- nents expressed in two different reference systems rotated by any angle allows us to find this angle. Knowledge of the angle between reference systems and the strain in the sys- tem rotated relative to the main axis, explicitly allows us to calculate the main strain, which is used to calculate Young modulus (Gładyszewska and Chocyk, 2004).
The analytic expressions of the free energy, the mean nearest neighbor distance between two atoms, the elastic moduli such as the Young modulus, the bulk modulus, the rigidity modulus and the elastic constants depending on temperature, concentration of interstitial atoms for interstitial alloy AB with BCC structure under pressure are derived by the SMM. The numerical results for alloy FeC are in good agreement with the numerical results for main metal Fe. The numerical results for alloy FeC with c C = 0.2% and c C = 0.4% at zero pressure are in good agreement with experiments. The temperature
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One of the key advantages of the particle-based DEM model is that microcracks are modelled as individual bond breakages and hence can be quantified. This feature offers an additional way of appraising the fracturing process in relation to joint frictional resistances by assessing the extent and rate of proliferation of cracks. The trend of development of the various modes of cracks at different joint frictional resistances is shown in Figs. 17, 18. For both rock masses with non-frictional joints (Fig. 17a) and rock masses with frictional joints (Fig. 17b–e), there is a dominance of shear cracks when compared to the popula- tion of tensile cracks. The disparity between the population of the two modes of cracks increases with time, but a threshold is observed for a joint friction angle of 27 where the difference between the numbers of the two modes of cracks is at the minimum. Above and below these value, the deviation between the numbers of tensile and shear cracks increases; the highest deviations occur when the joints are frictionless. Whereas the rate of creation of tensile cracks could be approximately described using a logarithmic expression, the rate of creation of shear cracks may be described by either a logarithmic or a polynomial expression, where the crack population is dependent on the elapsed time, t. Some equations that approximately describe the rate of development of tensile and shear cracks within the rock mass for different joint friction angles are presented in Table 5. For a rock mass with a joint friction
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If a relatively short sample is used (with the ratio l/d < 20) it is necessary to take into account the influence of the shear forces and the rotary inertia. There are two possible ways to do this: 1) solving the complicated frequency equation derived from the partial differential equation accounting for these influences, 2) using the simple formula (3) and multiplying the calculated Youngs modulus (or measured resonant frequency) by a correction coefficient.
outline, and internal structures of the uterus after emptying the bladder. Thereafter, transvaginal ultra- sonography was done at multiple views to evaluate the symmetry of the uterus, possible presence of uterine effusion and other lesions, and assess the endometrial echoes and thickness as well as the bor- derline between the endometrium and myometrium. The endometrial thickness was measured at the max- imal longitudinal section and recorded. Measurement was done at the middle point between the fundus of uterus and cervix. Then, SWE of the endometrium was performed with the SWE mode. The red, green, and blue colors represent high, intermediate, and low Young’s modulus, respectively. When the images became stable, the images were frozen, and quantifi- cation was done with the Q-BOX system. Young’s modulus of the anterior and posterior endometrium was measured. The diameter of region of interest (ROI) was 2 mm, and the distance between ROI and probe was 2–4 cm. The ROI was set at three sites of the anterior endometrium and three sites of the posterior endometrium (middle point between the fundus of uterus and cervix, 0.5 cm away from the
In this investigation, physical vapor deposited Ti-Cr-N coatings were coated on tool steel substrates using reactive arc evaporation. Microstructure and mechanical properties of coatings such as roughness, thickness, phase composition, hardness, Young’s modulus and coefficient of friction were studied. Phase compositions were investigated by X-ray diffraction method. Surface microstructure and morphology were studied using scanning electron microscope (SEM) and coating compositions were determined by energy dispersive spectroscopy (EDS). Mechanical properties were measured by nano indentation. The friction behavior of the coatings were investigated using ball-on-disc tests under normal loads of 7 N .The results showed that (Ti, Cr)N and TiN coatings consisted of only one cubic phase solid solution, while CrN coatings consisted of hexagonal Cr 2 N and cubic CrN phases. Average
Abstract. The design method of pavement structure is evolving to the new Mechanistic- Empirical (M-E) approach. A major benefit of M-E approach is being able to identify the distress patterns and the progress rate of a given pavement structure. This is possible by the knowledge of mechanistic characteristics of pavement materials responding to the repeated loads and environmental changes. Resilient modulus of the unbound granular material is the fundamental parameter needed in the mechanistic analysis of pavement structure. The resilient modulus behavior responding to moisture changes is the key contribution to the structural strength of conventional pavement in Thailand. This study investigated the resilient modulus of the road base materials for the M-E approach. In this research, a set of laboratory tests were conducted on unbound crushed limestone. Two gradations of the limestone were selected to determine the resilient modulus using the repeated-load tri-axial test according to AASHTO T307. Test results revealed that water content played a significant influence to the resilient modulus value. The resilient modulus characteristic of limestone UGM observed from these tests can be employed in Mechanistic-Empirical Pavement Design.
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Of substantial concern is the determination of E from a beam equation with assumptions that we violated in some way. The most pressing of these is the assumption that the deformations are caused solely by bending rather than shear, which is certainly true for very long thin beams. The literature for prismatic beams of bone indicates that if the ratio of supported length to depth is less than 15:1 then shear plays a substantial role and the modulus will potentially be substantially underestimated (Spatz et al., 1996). Our ratios ranged from 7.5 to 36, with many samples below the cutoff for solid beams. Because there is not even an empirical formula for hollow cylindrical structures we assessed the effect of aspect ratio on stiffness with a regression. There was no relationship between the two variables, and a breakpoint analysis did not show the expected decline in stiffness as the ratio decreased. We attribute this to the hollow cross-section of the beam. The beam equation also assumes a constant cross-section. Though there was a distinct taper to the ribs we chose a very short span so as to minimize the difference between cross-section at the two end supports and we measured first and second moments of area at the indenter. The gross appearance of the ribs is that of a monotonically tapering beam, so we would not expect more than a 10% difference in CSA from one end of the tested section to the other. The very slight curvature of the rib amounted to a ratio of radius of curvature to depth of more than 8, so we can ignore the curvature (Young and Budynas, 2002).
120°C. (See Table 3.2). At below glass transition, it can be observed that the E peak value decrease with higher volume fractions of glass fibers while for above the glass transition temperature, the E” value increase upon higher volume fractions of fibers. Previous research also has shown the same trend of E” values . Based on Table 3.2, 15SMPC have higher amount of E” for both below glass transition and above glass transition region. This shows that 15SMPC have good interfacial bonding between fiber-matrix. This is because a composite with poor interfacial bonding tends to dissipate more energy . Besides, it can be observed that the width of peak for SMPC becomes broader than pure SMP. This indicates that there are relaxations of molecules in SMPC which are not present in the pure SMP. These molecular motions at the interfacial region generally contribute to the damping of the material .
break the fibres to shorter lengths . The glass fibre strength is highly sensitive to elevated temperatures. A strength reduction of up to 90% was observed for fibres recovered using the fluidized bed process [1, 2]. Simple heat treatment of glass fibre bundles and single glass fibres also resulted in a significant strength reduction . Due to their decreased strength, recycled glass fibres were expected to show larger fibre length degradation during melt processing than pristine glass fibres. Discontinuous glass fibre polypropylene composites are suitable for high volume production and they can be used for semi-structural applications. The mechanical properties of glass fibre polypropylene composites are strongly influenced by the length distributions of the glass fibres. Thomason et al observed that the Young‟s modulus, tensile strength and impact resistance increase sharply with the fibre length up to a plateau . Thus an enhanced fibre breakage of recycled glass fibres during processing could also lead to a reduction of the mechanical properties.
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By investigating the vibration characteristic of wood as a soundboard, Norimoto et al. , Matsunaga et al.  and Kubojima et al. [7–9] found that the wood acoustic vibration characteristics were significantly affected by performance parameters, such as the dynamic elastic modulus E=q, elastic modulus and shear modulus ratio E=G, acoustic radiation damping coefficient R, and acoustic impedance x. Violins were ranked into different grades from the view of acoustic adaptability, esthetic suitability and comprehensive evaluation using a subjective appraisal method by Buksnowitz . In addition, the indexes of material property, including sound velocity, sound damping, resonance frequency, dynamic elastic modulus, rigidity, density, ring width, variable coefficient of tree-ring width, ratio of summer wood, fiber length, dimensional stability, and analyzed the material perfor- mance were also measured using multivariate linear regression method. The main acoustic properties of vene wood were determined using a test method of free–free flexural vibration (BING device) by Traore et al. .
The addition of fillers in the epoxy based adhesive has primary intention in improving the toughness and the mechanical properties. However the presence of the fillers will affect the curing characteristics of the adhesive which can lead to an increase or decrease the mechanical properties of the adhesive. Incorporation of nanofillers/nano -reinforcements into thermosets such as epoxy has attracted considerable interest indicated by the recent increase in the number of publications [1,2,3,4,5]. Research results show that the microstructure and properties of composites, such as thermal stability and rigidity are affected by modifier particle, particle size; concentration and particle shape [3,5,6]. Calabrese and Valenza  added CTBN to DGEBA-DGEBF epoxy resin there was an increase of the curing rate and they concluded that it was due to the catalytic effect of the CTBN carboxyl (-COOH) end groups on the cure process. Recent study by Thomas et al  on the thermal properties of epoxy based adhesive by varying the percentage of CTBN (5-20%) found that as the percentage of CTBN increases, the Tg and the storage moduli of the modified epoxies with lower content of CTBN are greater while that of a 20 phr blend is lower than that of the neat resin. At lower concentration, the phase separated CTBN leads to improved fracture toughness of the epoxy network. At a higher concentration, the liquid rubber flexibilizes the epoxy matrix and reduces the cross -linking density. The decrease in the storage modulus is attributed to the lowering of the cross - linking density and plasticization effect of the liquid rubber into the epoxy matrix.
Table 3 shows the indentation hardness and modulus of the coatings, as deposited and after a thermal annealing in air at 1000 ºC for the monolayer; and 1000 ºC and 1100 ºC in the case of the multilayer. The multilayer coating exhibits an indentation hardness of 29.8 GPa and a modulus of 219 GPa; whereas these for the monolayer are 25.2 GPa and 193 GPa respectively. Different values of indentation hardness are reported in the literature for Cr-Al-N, Cr-Al-O and a multilayer CrAlO/CrAlN . Arc evaporated CrAlN and CrAlSiN hardness as high as 35-40 GPa has been reported by Endrino et al  and Polcar et al . Khatibi et al  reported values from 24 to 30 GPa for arc deposited CrAlO films depending on the Cr/Al ration, and Najafi et al  in the range 33 to 25 GPa. Cr-Al-O sputtered coatings, on the other hand, exhibited hardness between 24–27 GPa . Raab et. al  found that the indentation hardness of CrAlO/CrAlN multilayers as the bilayer period increases. The hardness/modulus ratio H 3 /E’ 2 has also been calculated for the two coatings, as an indicator of the resistance to
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obtained and the results satisfy the Born’s criteria of lattice stability. The bulk modulus B, shear modulus G, Young’s modulus E, elastic modulus and Poisson’s ratio were calculated to be 30.36 GPa, 14.35 GPa, 37.19 GPa, 20.80 GPa and 0.296, respectively. The B/G ratio is derived to be 2.12, implying that the Li 10 GeP 2 S 12 is ductile according to Pugh’s criterion. The Van der Waals interactions