Papers by Keyword: Elastic Modulus

Abstract: Wheat lodging results in great losses of wheat production about 10%~30% every year. It is very important to study the lodging and to find new way to improve the quality of wheat stalks and its anti-lodging characteristics. The study about the changing of wheat stem mechanical properties with the elastic modulus and stem structure is carried on the basement of theoretical model, experimental improvement, and finite element method. Results show that the stem is more difficult to lodge if the ratio is bigger, which can be calculated through elastic modulus multiplying wall thickness and divided by diameter.

Abstract: The successful development of biomaterials is increasingly influenced by biomimesis essentially the use of biological structures as design templates. This approach has been used here in the design of injectable systems for the nucleus of the intervertebral disc, corneal inlays and intraocular lenses (IOLs). The strategy is based on the use of C-linked sulphonates to mimic the O-linked sulphate groups that are the hydration drivers in proteoglycans. The elastic modulus of the materials can be tailored for specific applications.

Abstract: The size-dependent elastic modulus of tungsten layers and wires is predicted according to size-dependent melting temperature model. The elastic modulus decreases with decreasing of size and the drop becomes dramatically once the size decreases below 3 and 6 nm for layers and wires, respectively. Moreover, the softening of elastic modulus for wires is nearly twice as large as that for layers when size remains the same. The accuracy of the model is verified by experimental and atomistic simulations results.

Abstract: Through the finite element method, the elastic modulus and Poisson ratio out of plane of the honeycomb nanoporous materials are obtained. In the end, the values are contrasted with the scale values. Results show that the values are same to the scale values.

Abstract: Three material properties (density, modulus of elasticity, bending creep deflection) of poplar wood modified with low molecular resin was examined and evaluated by an experimental approach. Poplar specimens were treated to achieve full penetration using a vacuum schedule with different low molecular resins. These resins were urea-formaldehyde (UF) and phenol-formaldehyde (PF) prepolymer solution. Creep tests were conducted under a varying climate with 16 °C ~ 31 °C and 40 % ~ 80 % relative humidity. The specimens were loaded in bending for approximately 140 days. Then the curves of the creep tests were analyzed to derive the development of bending creep performance. The results show modification leads to significant changes on material properties. Modification increases both the density and elastic modulus, and also tends to deflect creep deformation obviously less than untreated specimens.

Abstract: Concrete is one of the most widely used construction material throughout the world. But the properties of concrete under different strain rates differ from each other greatly. In order to investigate the effect of strain rate on concrete compressive mechanical properties, compressive experiments of concrete specimens (C35) are carried out on MTS, with the uniaxial strain rates ranging from 10-5/s to 10-2/s. The compressive mechanical properties of concrete under different stain rates, which include compressive strength, elastic modulus, peak strain and Poisson's ratio are studied systematically. The formulas which can describe the change laws of the compressive properties of concrete under different the strain rates are proposed. The test results show that the compresseive strength and elastic modulus of concrete would increase with the strain rate increasing. The effect of strain rate on peak strain and and Poisson's ratio is not significant. These research achievements can contribute to grasp the dynamic properties and build the dynamic constitutive models of concrete.

Abstract: Experiment with intensity level for the LC30 ceramsite concrete as the research object, changing the content of cement, GRT fiber, rubber powder by the orthogonal test to configure GRT fiber—rubberized haydite concrete samples, maintenance samples 28d in standard conditions and respectively testing their modulus of elasticity、standard compressive strength and apparent density. Through the analysis of the test data, using regression method to establish the GRT fiber—rubberized haydite concrete static compression modulus of elasticity experiential formula and use new test data to compare the value of calculation. By comparing test values and calculated values proved availability of the regression formula.

Abstract: Based on the numerically iterative technique, we introduce the shear modulus pattern used for accelerating convergence and rebuild the iterative program. Using this program, we analyze the bending problem of a bimodular deep beam under the action of uniformly distributed loads, in which the different ratios of span length to height of the beam, and of elastic modulus in compression to that in tension, are considered. The results show that the bimodularity have great influences on the bending stress and the deflection of deep beam.

Abstract: This paper does research in the independent development detection system for intensity of laminated veneer lumber via ultrasonic wave. By measuring the velocity of ultrasonic wave and other parameters on-line, the dynamic elastic modulus of laminated veneer lumber can be calculated through AVR as the data processing core of this system. And because of the dynamic elastic modulus showed positive correlation in plank strength, the timber grade can be divided through this system.

Abstract: The analysis of windshield against bird strike is necessary for reducing the disastrous consequences. The flat windshield which involves two pieces of glass together with a polyurethane interlayer is often used in the aircraft. The mechanical property of the polyurethane interlayer is an important factor of affecting the response of windshield against bird strike. This effect is investigated in this work by simulating the bird impacting the flat windshields with the polyurethane of different elastic modulus. The bird is modeled with SPH method. The calculation results indicate that the elastic modulus of polyurethane affect the response of windshields in many points. For the elastic modulus of 5 MPa, the thickness of polyurethane interlayer is compressed by 16% during the striking. The compressive effects decrease the contact force and the displacement of windshield to some extent. Especially, the major principle stresses in the inner and outer glass are decreased by the compressive effects significantly. It is found that the major principle stresses in the outer glass are 103 MPa lower than those of the case with the elastic modulus of 600 MPa. The relatively small stress in the glass means that the windshield can afford more serious impact and has the better impact resistance.