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The thermal properties and thermal stability of polypropylene (PP) composites separately filled with graphene nanoplatelets (GNPs) with three different sizes were measured using a differential scanning calorimetry and a thermal gravimetric analyser. The results showed that the values of the melting temperature of the composites were higher than that of the unfilled PP; the thermal stability increased with increasing the weight fraction and lateral dimension of GNPs in the case of low filler concentration, while the effect of the GNPs thickness on the thermal stability was insignificant; the onset decomposition temperature increased with increasing the GNPs lateral dimension, while the maximum thermal decomposition rate increased first and then decreased with increasing the GNPs weight fraction. The thermal stability improvement should be attributed to the sheet barrier function of the GNPs.

Microencapsulated red phosphorus (MRP)-filled polypropylene (PP) composites were prepared using a twin-screw extruder. The effects of load and temperature as well as the dispersion or distribution of the filler particles in the matrix on the melt volume flow rate (MVR) and melt density ( ρm) of the PP/MRP composites were investigated using a melt flow indexer and a scanning electron microscope. The temperatures and loads were varied from 180 to 205°C and from 2.16 to 12.5 kg, respectively. The results showed that the MVR of the composites increased nonlinearly with increase in temperature and load. The sensitivity of MVR of the composite melts to temperature was significant. The MVR of the composites also decreased slightly with an increase in the MRP weight fraction. However, the values of ρm of the composites varied slightly with increase in load, temperature, and MRP weight fraction. The findings can provide useful information for optimum processing of these composites.

In this study, an ionic polymer—carbon nanotube composite (IPNTC) was developed to function as a new configurative actuator. The IPNTC was fabricated with carbon nanotube-reinforced ionic polymer as electroactive middle layer and functional multi-walled carbon nanotube (MWNT) diaphragm as electrode layers coated on the two sides of the membrane. Scanning electron microscopy images show that the interface between functional MWNT-diaphragms and polymer membrane has strong adhesion. Furthermore, the MWNT-diaphragm has a uniform dense porous structure, and MWNTs entangle and interpenetrate each other. The IPNTC actuator has remarkable displacement output under low-voltage stimulation and it can last for 3000 cycles with only 10% reduction in the displacement output.

This paper presents an experimental remeshing process for the large strain analysis of fine-blanking. The research is to be carried out mainly because the severe and localized deformation of fine-blanking greatly obstructs the measurement of strains. In order to solve this problem, a new experimental remeshing process was developed to measure the strain in the major deformation areas of fine-blanking. Without this newly developed process, a more intensive and practical strain analysis of fine-blanking could not have been achieved. Therefore, a study of this remeshing process, with a step increment of 20 per cent, until the total punch penetration is 80 per cent of the material's thickness, is to be performed to verify its effectiveness. Low-carbon steel sheets of JISG3101 were used to split blanks. As a consequence, findings showed that an increase in the total punch penetration will clearly induce an exponential increase in the effective strain, and the severity of deformation will be augmented with the increase in the total punch penetration.

A multilevel superelement technique is applied to model the effects of circular voids on the effective elastic properties of a porous material. A twodimensional representative volume element with a circular void in its center is initially modeled by a superelement. A thin plate of porous material with a macrocircular hole in the center is constructed with this superelement. The finite element computation is then conducted to estimate the effective Young’s modulus, Poisson’s ratio, and the shear modulus of the material using the ABAQUS code for different void sizes. The values of the isotropic damage variables, DE and DG, under various degree of damage are hence determined. These values are compared with those calculated by using a conventional micromechanics damage model. A new isotropic damage model is proposed based on the results of this analysis. To demonstrate the applicability of this damage model, an example case of a notched cylindrical bar under tensile loading is investigated.

An experimental study has been performed to investigate the shear damage mechanism of aluminium alloy 2024T3 by an in-situ single shear test using scanning electron microscope (SEM). The observation of microstructural change and measurement of shear strain in mesoscale have been undertaken simultaneously. Hence, the shear damage mechanism and the shear stress–strain curve have been obtained. By measuring the deformed grid of a laser-marked sample, the shear strain distribution has also been found. On the basis of the experimental results, the relation between the shear damage evolution and the corresponding shear stress–strain state have also been obtained. It has been observed that two groups of microshear bands were formed in the shear process. When the shear stress is close to the shear strength of the alloy, slipping within the microshear bands occurs. The causes of macro-shear band formation and the interrelation and interaction among different types of microdefects are also discussed.

The tensile, impact and bending properties of calcium carbonate (CaCO3) filled acrylonitrile-butadiene-styrene copolymer (ABS) composites were measured at room temperature. It was found that the tensile modulus increased nonlinearly with increasing the weight fraction φ + of the fillers, and the tensile strength and tensile fracture stress decreased gently with the increase of. The Charpy notched impact strength decreased quickly when φ≤ 10%, and then decreased gently with increasing φ. While the bending strength increased when φ≤ 10%, and then it decreased gradually with increasing φ. However, the effects of filler size and its surface treatment on these mechanical properties were insignificant. Furthermore, the Vicat softening temperature (TV) of the samples was measured at a constant loading and a temperature ramp rate. The result showed that TV increased with the addition of. It indicates that CaCO3 fillers are beneficial to improve the heat resistant properties of the resin.

In this study, double scalar damage variables have been used to characterize the state of isotropic damage. The damage influence tensorrelating to the double scalar damage variables of damaged material isthus formulated based on the hypothesis of stress equivalence for this model. The specific damage energy release rate is adopted to represent the thermodynamics force conjugating to the double damage variables. Based on the irreversibility laws of thermodynamics, these forceshave been formulated directly from the degradation of effective engineering elastic coefficients in stress space. The contribution of bothdilatation and distortion of material to the specific damage energy density release rate in loading process has been explained. The doublescalar damage variables of isotropic solid material with penny-shape cracks and spherical voids randomly distributed have been determined on the basis of the micro-mechanics theory, respectively. In addition, the damage influence tensor and the specific damage energy release rate were obtained by using the experimental results of pre-strained aluminum alloy 2024T3 specimens under uni-axial tension tests.

An experimental method used to measure the Young's modulus of the conductive thin film is proposed in this paper. This technology has utilized the electrothermal effect and strain response of conductive thin film coatings on glass substrates. On the basis of the thermo-elastic analysis of composite mechanics, the measurement principle and corresponding formula are given. The Young's modulus of conductive SnO2 thin film has been estimated by means of the formula and the thermal bend beam test presented.

A strain based orthotropic elasto-plastic damage theory is derived for solving engineering problems. The basic ideas of the formulation are first explained by the one-dimensional approach. Subsequently, the approach is generalized to develop the theory in three-dimensional space. Damage is characterized by a second order damage tensor D while its effects on mechanical properties are described by a fourth order damage effect tensor M. The concept of elastic energy equivalence is adopted to determine the stress-strain relation in terms of the effective stress and the effective strain. On the basis of the plastic flow rule and the damage potential, the elasto-plastic damage tangent tensor as well as the damage threshold function are obtained. Since the development of damage usually connects with deformation, the strain based theory is easier to use in solving structural problems. An example case of uniaxial stretching of aluminium alloy 2024T3 plate is employed to justify the applicability of the theory. The...