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Two silane-based hybrid coatings were developed to modify the surface energy of phenolic resin impregnated paper. The coated paper samples were further pressed onto surfaces of plywood. The surface properties and water repellence of coated paper were investigated by AFM, XPS and water contact angle measurements. The water absorption of plywood with pressed paper was studied by water uptake tests. It was found that the sol-gel coatings had slightly improved the water repellence of the impregnated paper. The water absorption of plywood was also slightly decreased.

A multiscale constitutive framework for Ni-base superalloys has been developed, in which an efficient unit cell is adopted to describe the γ/γ’ microstructure morphology. The framework enables the prediction of the deformation and the creep and fatigue damage accumulation in CMSX-4 for a range of temperatures and stress levels. Moreover, the material microstructural degradation due to rafting and isotropic coarsening can be simulated, and the effects of this degradation on the alloy mechanical response can be quantified. The present paper focuses on the application of the model to real gas turbine components. A high pressure turbine blade finite element model is used to demonstrate the computational efficiency of the multiscale framework. Moreover, the location of critical regions and the life time are shown to differ from the results obtained from classical models that neglect the microstructure evolution.

Effect of Si content of Al-Si matrix on roll cast wire inserted strip was investigated in this paper. 99.5%Al, Al-4%Si , Al-12%Si and Al-18%Si were used as matrix. Slit depth of the nozzle, superheat of melt, wire-diameter and roll speed was chosen as the casting parameters, too. Addition of the Si was useful to prevent the reaction between the matrix and the wire. A downward melt drag twin roll caster could cast the wire inserted strip of the Al-Si matrix of which Si content was ranging up to18%. Composite strip, which matrix was hyper eutectic Al-18%Si, could be cast at the speeds up to 20m/min. The gap between the wire and matrix became thin when the superheat was high. When the slit depth of the nozzle was too shallow, the wire could not be inserted in the strip. The thickness of the wire inserted strip became thinner as the roll speed became higher.

Authors’ group has been done researches on the damage monitoring of the laminated Carbon Fiber Reinforced Plastic (CFRP) using the electrical resistance change method. The method adopts reinforcement carbon fibers as sensors, and it is called self-sensing method. Using thin CFRP laminates, delamination crack location and dimension are identified with the electrical resistance change method. However, the electrical resistance decreases when a delamination crack is made in a thick CFRP beam. The present paper experimentally investigates the effect of the dent for the measurements of electrical resistance change. Indentation tests are performed for the thick CFRP plates. The effect of the dent is calculated compared with the effect of piezoresistivity caused by the residual stress relief. As a result, the effect of the dent is larger than the effect of the residual stress relief for the thick CFRP. For the thick CFRP, dents cause the significant reduction of the electrical resistance in the thickness direction, and that causes electrical resistance decrease.

Experimental works using a drop weight impact test method have been performed on a circular sheet specimen to evaluate and to characterize the impact resistance of the sheet-type plastic components designed for automotive wheel covers. Evaluation has been conducted for a set of engineering plastics: polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS) and their blend (PC/ABS). The testing results showed that the PC/ABS blend specimens failed in brittle manner under higher impact speeds with very few of whitening zones. Secondary cracks captured perpendicular to fracture surface were also found in the mid-plane of the scattered PC/ABS blend specimens. Investigation is then focused on this blend and the testing results describe that impact resistance of the specimen made of this alternative material is determined by ABS not by PC. Combination of structures between PC and ABS through the thickness in the core due to their immiscibility was observed by scanning electron microscope (SEM) on the etched PC/ABS specimen. This latter result well correlates the results obtained from the testing. It therefore reveals that immiscibility between PC and ABS in the blend plays an important role in determining the impact resistance of the components. This paper also presents simulative results of the test obtained from a FEA work by introducing a 3D- layered finite element (FE) model of the PC/ABS specimen to take into account effect of a layer in the core on the behavior of the blend.

Thermomechanical fatigue (TMF) in superalloys is growing in importance due to the introduction of advanced cooling systems but also due to the changes in demand and competition within the power generation market; this is requiring many power plants to operate under cyclic conditions. In this paper the TMF behaviour of three different single crystal nickel-based superalloys are compared. It is demonstrated that the deformation and damage mechanisms occurring during TMF are rather different from those traditionally reported for creep or isothermal fatigue. In all cases examined, the deformation is localized within a rather small number of deformation bands. While these bands were found to consist mainly of micro-twins in some alloys, in others they might be better described as slip or shear bands. Furthermore, in some circumstances these bands are prone to recrystallization. In CMSX-4, the intersection points of twins of different orientation act as initiation sites for this process. In the SCA425 alloy - of smaller gamma' content, lower creep resistance and less great oxidation resistance - twinning is observed infrequently; however the deformation is still very localized and in the distorted gamma-gamma' microstructure, along the shear bands, recrystallization is observed. Furthermore the recrystallization is enhanced by oxidation due to the development of a gamma'-depleted zone. In CMSX-4, TCP phases precipitated during long term ageing cause a more dispersed deformation behaviour which prevents recrystallization. Our findings confirm the importance of an inhomogeneous microstructure for good TMF resistance. © (2011) Trans Tech Publications Switzerland.

In this paper, Saint-Venant end effects for plane deformations of transversely isotropic piezoelectric materials are investigated. The stress decay rates in linear piezoelectric strips that are traction free with two kinds of electrical boundary conditions are considered. The characteristic equations for decay rate are obtained for symmetric and antisymmetric deformations. Numerical values are given for the roots with the smallest positive real part, which are associated with the slowest decay. Saint-Venant end effects of piezoelectric materials of crystal class 6mm penetrate much further into strip than those of elastic isotropic materials.

This paper presents the possible deviations between “realistic” (performance-based) calculations of fire resistance of steel structures and corresponding calculations made by one of the often used simplified (prescriptive) procedures of EN 1993-1-2 i.e. the method of critical temperature (MCT). The comparison is done for a case of an assembly consisting of a steel beam and a steel girder connected to each other by a bolted fin-plate connection. For such structure the MCT method suggests that the structural fire resistance is 50 minutes. However, the realistic fire resistance calculated by an advanced performance-based procedure is evaluated to 44 minutes. Although the discrepancy between the results of both methods is not significant in the presented case, this finding implies that MCT can be on the unsafe side for some cases. More future debates and clarifications are therefore encouraged regarding the actual limits of the applicability of the simplified procedures.