Applied Mechanics and Materials Vols. 52-54

Abstract: In this paper, the free vibration analysis of thin rectangular plate with dowels on nonlinear elastic foundation is investigated. The load transfer on dowels is modeled as vertical springs, whose stiffness depends on the dowel properties and the dowel-plate interaction. Based on Hamilton variation principle, the nonlinear governing equations of thin rectangular plate with discontinuities on nonlinear elastic foundation are established, and the suitable expressions of trial functions satisfying all boundary conditions are proposed. Then, the equations are solved by using Galerkin method and harmonic balance method. The numerical simulation reveals the effects of the dowel parameters and the other ones of the system on free vibration behaves of the disconnected thin rectangular plate.

Abstract: In traditional hulling machine, The lower of shelling rate and higher of breakage rate of castor. The self-designed hulling machine is adopted in this issue to study the prosess of capsule hulling. By analyzing the state, As gap between rollers reaches the minimum space, distortion from capsule to roller surface reaches the maximum, as the same as both the pressure of roller surface on castor-oil plants P and friction force F which indicates the strongest effect of extrusion and rubbing. the required condition of capsule rolling is that the angel of rolling（ ） should be no larger than frictional angel of roller（ ）. The highest shelling rate and lowest of breakage rate can be gained by using a steel matrix roller coated by plastic with 10r/min rotation rate of rollers and 18mm gap between rollers.

Abstract: The fixture of motorized spindle plays a definitive role in clamping stability and working reliability. If designed irrationally, not only will affect the precision of the micro-milling machines, but also cause the spindle drop. Based on the phenomenon that the spindle drops at high-speed in micro-milling process, this paper optimized the existing fixture, designed the supporting protective device, and analyzed their static characteristics utilizing ANSYS finite element analysis software. To guarantee the sufficient strength of bolts on the fixture and the protective device, both the theory analysis method and ANSYS finite element analysis method are used to make the strength check of the selected bolts. The optimization of the fixture for high speed motorized spindle has far-reaching affect on the design of high-speed motorized spindle.

Abstract: This paper presents the extensions of newly developed finite element (FE) formulation to evaluate fracture behavior of parallel edge cracks problems. The numerical formulation used Barsoum singular finite elements to compute fracture parameters in two dimensional finite element models subjected to different crack-width ratio and cracks interval ratio. Mixed mode stress intensity factors (SIFs) of parallel edge cracks are computed in extending of FE formulation for pure Mode I formulation proposed by authors. In 2D linear elastic problem under mixed mode condition, the variation of SIF value near crack tips are discussed comprehensively. The newly finite element formulations are resulted with remarkable agreement with energy release rate based method compared to analytical solution available in the literatures.

Abstract: Konjac glucomannan (KGM) belongs to pseudoplastic fluid. Remarkable non-linear change tendencies of shear rheological behavior of KGM were detected through analysis of the correlation of viscosity (η)-shear rates and shear stress-shear rates respectively, and its shear rheological curves conformed to the Power Law (τ=ＫDn). The change tendencies of viscosity factor (K) and flow index (n) correlated with concentration and temperature were also obtained, the curves can be fitted by power and quadratic polynomial equation respectively. The acquired non-linear correlation curves of K and n can provide reliable foundation for rational applications of KGM in food industry and its grade estimation.

Abstract: In this paper, the effect of environment factors on KGM molecular dimension was discussed, such as ultrasonic, enzyme, concentration and temperature. The KGM polarity, molecular weight (Mw) and conformation were analyzed by digital polarimeter and LLS. The result indicated that the polarity change influenced by temperature and ultrasonic accorded with linear function equation. Mw of KGM gradually decreased with ultrasonic time and concentration of enzyme increase. The concentration of KGM was lower, the effect was more obviously. The changes of KGM Mw also brought regular change of molecular conformation. All offers the reference to reliabletheoretical foundations on controlling KGM molecular dimension and industrial application in exploiting KGM potential function and activity.

Abstract: The improvement of the preparation method for carboxy methylation of konjac glucomannan (KGM) was proposed in this paper according to molecular structural characteristics of KGM. Carboxymethyl konjac glucomannan (CMK) were yielded by first blending KGM with etherification agent and then basifying and catalyzing in ethanol. Through single factor and orthogonal experiments, the effects of reaction conditions on degree of substitution (DS) and apparent viscosity (η) were investigated, and the optimum reaction conditions were obtained as follow: 55°C, pH12 for 3 hours. The results indicate that the maximal value of DS and η were 0.5278 and 15.57Pa•s respectively. The reaction mechanism for carboxymethyl of KGM was proposed and checked by infrared spectra. Meanwhile, it is showed that the properties of CMK were rather good in terms of hydrated rate and hydrosol transmittance.

Abstract: In this paper, the relativity on the granularity with different mesh of konjac glucomannan (KGM) and molecular dimension was discussed. Laser particle size analyzer, laser light scattering and digital polarimeter were used to analyze the granularity distribution, molecular characteristics and polarity of KGM. The results showed that the granularity of KGM after gradient refining was gradually decreased and KGM was well dispersed in ethanol(D50=13.11μm).The Mw of KGM was gradually decreased with its granularity decrease and its molecular conformation was from globular to linear structure. The space asymmetry of KGM at 80-100 meshes was minimum and its polarity was maximum. The primary establishment on the relativity offered the references to KGM theoretical research and practical application.

Abstract: In the area of alluvial soft soil, the double layer subgrade with rigid upper layer and soft lower layer is common. In such subgrade, the stress diffusion phenomena will occur under vertical load. In this paper, the stress and deformation of such subgrade are studied by ABAQUS. According to the calculation results, the plastic zone of subgrade appears in the upper layer soil of the interface, and then, it expands up and down the interface with the increase of load. The plastic zone expands rapidly in the lower layer soil. Finally, the subgrade gets up to its ultimate bearing capacity when the plastic zone reaches the foundation bottom. This results provides an effective analytical methods to the engineering designers. It has practical meaning.

Abstract: In order to prevent shear locking, a method using theory of deep beam is proposed. A universal finite element for thick and thin plates is constructed. When the plate thickness approaches to the limit of thin plate, the universal element degenerates to the thin plate element automatically. As a results, the shear locking phenomenon will not appear. The computational results indicate that the current element has high-accuracy and good usefulness.