CAD/CAMsystems CEREC and LAVA and to evaluate the amount of load required to delaminate the veneered ceramic from zirconia core of two systems. In a previous study, the zirconia-veneer bond strength was inferior when compared to other all-ceramic systems, which suggests that the zirconia framework layered with ceramic are more susceptible to delamination and chipping under function.  In this study the type of zirconia frame work used was the white colour and no surface treatment was carried out on the zirconia surface before layering ceramic on to it. The shear bond strength of zirconia and its veneered ceramics of two CAD/CAM systems CEREC and LAVA were evaluated. This study consisted of total 40 samples, 20 samples belonging to group A (CEREC) and 20 samples belonging to group B (LAVA). The samples were later tested for the shear bond strength at the interface between zirconia and ceramics. Samples were loaded with shear stress using universal testing machine. The ultimate load at which the delamination of ceramic occurred was recorded in Newtons and the shear bond strengths were calculated in Megapascals (MPa) by dividing the load (N) at which failure occurred by the bonding area (mm 2 ). Shear stress (MPa) = Load (N)/ Area (mm 2 ) Where bonding area is calculated by formula length x breadth i.e,. Area = 5mm x 4mm = 20mm 2 . In group A the maximum shearstrength recorded was 7.78 MPa and the amount of load required to delaminate the ceramic is 155.6N. In group B the maximum shearstrength recorded was 18.45 MPa, and the amount of load required to delaminate the ceramic is 370.9N. The probable reasons behind the enhancement of overall strength of all ceramic restorations include the coefficient of thermal expansion of veneering porcelain and core material. It was proved that, for metal ceramic restorations, veneering porcelain with a slightly lower coefficient of thermal expansion compared to that of framework material is recommended. The concept behind
The microstructure examination from scanning electron microscope of the cast composite revealed uniform distribution of particles. The Addition of silicon carbide (SiC) particles resulted in increase in density and porosity and it further increases with increase in percentage of particle fraction. Hardness of Al-SiC composite increases with increase in percentage fraction of SiC particles. Due to formation of weak compounds in the interface of the matrix and silicon carbide reinforcement, the ultimate tensile strength of composites decreases with increase in silicon carbide (SiC) fraction of cast composite. Wear rate reduced with increasing content of silicon carbide reinforcement which acts as obstacle for shear deformation.
With regard to failure modes, two types of failure for masonry panels subjected to diagonal compression test as can be expected. Masonry without concrete cores, demonstrated non-diagonal brittle failure in which cracks developed through brick mortar interface without crushing the bricks (Fig. 10a) while reinforced specimen showed diagonal failure in which cracks developed from bot to top of the specimens dividing the sample in two parts, almost symmetrically (Fig. 10b). Non-diagonal failure counts as a brittle failure in against diagonal type. In contrast to unreinforced panels, reinforced panels preserved the monolithic after the failure and they present a less brittle failure than the unreinforced one. Mentioned difference and points can be observed on load-displacement diagrams as illustrated on Fig. 11, 12. As it can be seen, the diagram recorded for coreless panels shows a brittle failure while the diagram concerning the reinforced specimen with concrete core shows descending path after the maximum load. It should be specified that in the case of CRM 1, load-displacement diagram does not describe post peak behavior because the execution of performed test was interrupted after reaching the maximum load value. It is worth noting that in the case of specimens without cores, failure occurs because shear stress exceeds shearstrength of the mortar used to realize the joints while specimen with concrete cores fails because tensile stress of the panel exceeds ultimate tensile strength of masonry.
During vacuum hot rolling activation of surfaces occurs at the expense of their shearing plastic deformation that promotes the fracture of oxide film on joined surfaces . On pure (juvenile) surfaces activation  centers are produced  associated with the escape of dislocations on surface. If dislocations that provide the elastic defor- mation produce dipoles of wedge disclination and appear on metal surface into the area of physical contact then they are the center of disturbance. Each disclination may represent  effective way of fluxes of heterogeneous materials atoms directed towards each other. Mutual transport of atoms and energy transfer occurs by these channels that balances all the system. Further deformation of material causes the advance of metal atoms that have increased energy and displacing by produced channels of defected structure on long distance. In experi- ments atoms of metals were detected that were displaced into crystalline lattice of other material on depth up to 20 mkm. On interface of two metals the flux of heterogeneous atoms sets up directed in opposite directions. Due to this in the narrow range (1 - 5 mkm) random rearrangement of two joining lattice occurs and the zone with mixed distribution of atoms of two materials forms on the interface of solid phase joint.
, Gireesha and Muthukkumaran . Since the mentioned areas are heavily industrialized and populated, the importance of offshore clay as a foundation soil, particularly for harbor and ports has led to several investigations of its geotechnical characteristics [1, 12]. Although, at the regions where the offshore clay exists, structure foundations have adopted using pile foundation as subsurface supporting structures (i.e. heavy structures such as harbor and port). The interfaceshearstrength between pile and offshore clay has not completely investigated yet. Therefore, it is crucial to examine the interfaceshearstrength of pile materials (steel plate) and offshore clay to have a reliable and cost-effective design of friction pile foundation structures. Hence, the interfaceshearstrength parameters can be used in stability analysis [6- 8, 10]. This study focuses on the effects of moisture content variations on the interfaceshearstrength of three different steel surfaces, namely smooth, corroded, and rough steel surface with offshore clay. The main objective of this study is to evaluate the interfaceshearstrength between offshore clay and steel plate under application of different water content. In summary, a notable discovery is that the offshore clay-interface rough steel surface can be sustainably applied for construction of steel structures in offshore clay without sliding. However, sufficient laboratory and field testing are required.
Abstract: Ball shearstrength of the thermosonic wire bond interconnection relates closely to the reliability of the microchip during performance of its function in any application. Concerns regarding the reliability of Cu wired electronic microchips are raised due to formation of void at the copper (Cu) wire- aluminium (Al) bond pad bonding interface, predominantly after high temperature storage (HTS) annealing conditions. The interfacial void formation is suspected originated from a volumetric shrinkage during the growth of the Cu-Al intermetallic compound (IMC) layer in the Cu–Al bonding interface. In this report, the ball shearstrength and interfacial microstructure of the thermosonic Cu wire-Al bond pad system bonded at difference temperature (150 °C, 280 °C and 400 °C); and annealed at different HTS durations (as-synthesized, 500 hours and 1000 hours) were studied. It was observed no significant difference in the mean of the ball shearstrength of bonds bonded at different temperature before HTS treatment. On the other hand, the ball shearstrength increase with the HTS duration. This is due to the fact that higher bonding temperature and longer HTS promoted better growth of the Cu-Al IMC layer. A transmission electron microscopy - energy dispersive X-ray analysis (TEM-EDX) has also been carried out to observe the formation of the Cu-Al IMC layer in the sample.
Some examples of the use of SMA method to assess ultimatestrength of isolation system based on elastomeric have been presented. The examples concerned 2 possible failure modes of the SIS: isolators failure in shear or isolators buckling. Analysis was based on simplified approaches (only one direction of seismic horizontal loads concerned) but despite the limited number of examples and failure modes investigated, these examples have shown that:
P-y curve model has been a practical and effective method in investigating performance of laterally loaded pile. P-y relationship recommended by American Petroleum Institute has been used widely in analytical and numerical analyses. Two characteristic parameters of p-y relationship are modulus of subgrade reaction, which is selected based on shearstrength parameters, and ultimate resistance, which can be computed from soil friction angle or undrained shearstrength, pile diameter and loading properties (API, 2000). Therefore, soil laboratory experiments or/and in-situ investigation data are necessary for generating p-y curves. Three-dimension numerical simulation is a powerful tool to analyze complicated soil-structure interaction problems. With a proper soil constitutive model and model parameters, the simulation can perform deformation analysis at high level of accuracy. Constitutive model and model parameters are most important input for the analysis. Model and its set of parameters are normally calibrated by regression analyzing data of completed experiments on structural systems.
In this project work, an attempt is made to predict the shearstrength for concrete deep beams at ultimate state, using ANSYS12.1 software. Two test beams will be accounted to predict their shearstrength at ultimate state using ANSYS 12.1 software. The accuracy of the predicted values of shearstrength based on ANSYS 12.1 software for the two test beams will be compared with their corresponding experimental results. In addition, the predicted values of shearstrength for the two test beams using ANSYS 12.1 software will be compared with the results obtained by shearstrength prediction models proposed by various researchers. The prediction of shearstrength using ANSYS 12.1is found to be reasonably in good agreement with the corresponding experimental results.
combined action of moment and shear taking the size effect into consideration is evaluated at the formation of diagonal tension cracks and at ultimateshear failure by using a method that combines both dimensional analysis and statistical analysis. Several sets of experimental data were carefully selected such that the influence of each basic variable (i.e., longitudinal steel ratio , concrete compressive strength f c ' , shear span to depth ratio a / d or beam size d ) can be separately evaluated. Comparison with existing experimental results as well as with four existing models supports the validity of the two proposed models in predicting and explaining the observed behavior of slender RC beams ( a / d 2 . 5 ) without web reinforcement.
High rise building is a structure vertically cantilevered from the ground level subjected to axial loading and lateral forces. It consists of frames, beams, shear walls, core walls, and slab structures which interact through their connected edges to distribute lateral and axial load imposed to the building. Lateral forces generated either due to wind blowing against the building or due to the inertia forces induced by ground shaking which tend to snap the building in shear and push it over in bending. These types of forces can be resisted by the use of shear wall system which is one of the most efficient methods of ensuring the lateral stability of tall buildings.
Sabouri-Ghomi et al. (2005) presented Plate Frame Interaction Model (PFI)of the Ductile Steel Plate Wall (DSPW). This model describes the interaction of various components and also the system’s overall hysteretic characteristics. Vian et al. (2009) conducted an experimental investigation of specially detailed ductile perforated steel plate shear walls. The special perforated panel SPSW specimen with multiple regularly spaced holes exhibited ductile behavior during testing and is a viable alternative to a solid panel SPSW, to allow utility access through the panel without the need for stiffeners around the perforations. The tested specimens also had low yield strength steel infill panels.
Abstract. An experimental investigation is carried out on the failure mechanism of foam concrete with cold formed steel double C-Channels embedment. The foam concrete is made of cement and fly ash with a compressive strength between 9 and 24 MPa with different densities. Forty-eight tests have been carried out in four groups of specimens with various embedment depths of the steel in the concrete. Four modes of failure are observed, which include the independent failure of the C-Channels with and without a concrete block inside the channel as well as the combined failure of the two channels, and the failure of the extrusion block. A theoretical model has been developed to understand the failure process. The peak compressive force applied onto the C-Channels that causes failure is calculated. It is concluded that the failure involves independent slippage between two C-Channels, and the steel and the foam concrete blocks inside the C-Channels. A method to calculate the peak force is also developed based on the test results. The calculations also show that the shearstrength of the foam concrete is about 8% of the compressive strength with coefficient of 0.4 between the steel and concrete.
This paper investigates the effect of tack coat types, application rates, and layer thickness on HMA interfaceshearstrength. The performance of tack coat materials on AC 10 was evaluated. Three emulsions were selected as tack coat material which are RS-1K, RS-2K, and RS-2KL.These tack coat materials were applied at three application rates, namely 0.25 l/m², 0.40 l/m², and 0.55 l/m². The selected application rates are in accordance with the JKR specification and represents low, medium and high rates respectively Three different surface thickness were considered namely 35 mm, 50 mm and 65 mm. Only laboratory scale specimens at three replicates for each test configuration were used throughout the study. Direct shear test were carried out shearing rate of 1 mm/min. Results show modified emulsion can provide better shearstrength than conventional emulsion where RS- 2KL performs better than RS-1K and RS-2K due to the present of latex in RS-2KL which relate to the viscosity that can improve shearstrength. On the other hand, higher thickness of wearing course and application rate can provide higher interfaces shearstrength. However, their relationships were not strong due to inconsistency of R 2 values.
Figure 10(a) shows the cross section of the interface be- tween the Sn3Ag8Bi5In and Ni/Cu/Cr UBM that was sol- dered at 513 K for 10 s, and Fig. 10(b) shows the result of the EDS-analysis of Sn, Ni and Cu, which are thought to be the active elements producing the IMC’s along the indicated line in Fig. 10(a). In Fig. 10(b), the left side indicates the sol- der and the right side indicates the UBM. In this figure, Sn- and Cu-content show higher values on solder and Cu-layer respectively. On the intermediate position between the solder and the Cu-layer, the Ni-content that originated from the Ni- barrier shows higher value. However, an unexpected small Cu-peak was found in the Sn-rich zone, as shown in Fig. 10(b). This indicates that Cu, originated from the Cu-layer, diffused through the Ni-barrier and moved into the solder. In order to determine the reason for Cu diffusion, AFM analysis was carried out on the Ni-layer (Fig. 11).
Reinforced concrete is the most prevalent composite material used in construction in the world and particularly in North Cyprus . Over the years the number of reinforced concrete structures has significantly rise from the year 1993 to 2016 according to data provided by State Planning Organization, (2016). This implies there is need for reconsideration in materials and methods of construction such as use of sustainable materials. Certain problems are associated with reinforced concrete structures in North Cyprus, some are; lack of quality control, inexperienced labourers, inadequate foundation isolation, inadequate vibration of concrete and lack of soil investigation . These aforementioned problems in one way or the other results to cracks, honeycombing, segregation and subsequently corrosion of reinforcing bars. Corrosion is the most alarming factor that causes deterioration of RC structures over time preventing them from meeting their designed service life . There has always been an interest for a material having both extreme strength and ductility. Strength gives a member the ability to carry load safely while ductility avoids sudden failure. Although steel has been the best option for years but corrosion exists as a setback to its overall performance . Use of fibre reinforced polymer (FRP) bar as internal reinforcement in concrete elements is one of the preferred solution adopted around the world due to its positive results over the years .
Abstract: Steel plates in double skin composite (DSC) panels are restrained by a concrete core and welded stud shear connectors at discrete positions. Local buckling of steel plates in DSC panels may occur in a unilateral mode between stud shear connectors when subjected to combined states of stresses. This paper studies the local and post-local buckling strength of steel plates in DSC panels under biaxial compression and in-plane shear by using the finite element method. Critical local buckling interaction relationships are presented for steel plates with various boundary conditions that include the shear stiffness effects of stud shear connectors. A geometric and material nonlinear analysis is employed to investigate the post- local buckling interaction strength of steel plates in biaxial compression and shear. The initial imperfections of steel plates, material yielding and the nonlinear shear-slip behavior of stud shear connectors are considered in the nonlinear analysis. Design models for critical buckling and ultimatestrength interactions are proposed for determining the maximum stud spacing and ultimatestrength of steel plates in DSC panels.
Collagen fibers are the main load bearing structures in the arterial wall at large deformation and are known to be responsible for the high strength of arterial tissues subjected to tensile and shear loading. The elastin network in the media, including elastic lamellae, interlamellar elastin fibers, and radial elastin struts, certainly contribute to the shear properties at small deformation. However, the contribution of the elastin network to the shearstrength behavior is small since failure occurs at large deformation. Moreover, for aneurysmatic and dissected tissues the contribution of the elastin network is very small, because elastin is usually disintegrated in such diseased tissues. Studies on aortic aneurysmatic tissues by, e.g., Tong et al. (2013), revealed a very low elastin contents in the abdominal aortic aneurysms due to pathological changes and remodeling. The collagen architecture, visualized by second- harmonic generation (SHG) imaging (Fig. 8), suggests that the large difference in the ultimateshear stresses may be related to the collagen fiber orientation and dispersion. From Fig. 8 one can appreciate that the collagen fibers embedded within the parallel planes to the plane of shearing have only little resistance to shear displacements. In other words, fibers embedded in the zθ-plane hardly contribute to the resistance of the specimen which is being sheared in the zθ-plane (‘in-plane’ testing modes). However, this is an idealization of the real structure. One should consider that the collagen fibers embedded in these parallel planes are interconnected by, e.g., proteoglycans, smooth muscle cells, and remaining elastin network, which might also contribute to the shearstrength. Furthermore, the dispersed fibers connecting these parallel planes create a resistance in the planes normal to the plane of shearing. For example, out-of-plane fiber dispersion will resist shear displacement under ‘in- plane’ testing. We expect that the resistance to shearing, hence the shearstrength, to be correlated with the mean fiber direction and the in plane dispersion of the fibers in the case of ‘out-of-plane’ testing, and with the out-of-plane fiber dispersion in the case of ‘in-plane’ testing (for the definitions of mean fiber direction and fiber dispersion see Holzapfel et al., 2015).
Concrete is the most common material for construction. The demand for concrete as a construction material l eads t o the increase of demand for Portland cement. Concrete is known as a significant contributor to the emission of greenhouse gases. The cement industry is the second largest producer of the greenhouse gas. The environmental problems caused by cement production can be reduced by finding an alternate material. One of potential material to substitute for conventional concrete is geopolymer concrete. Geopolymer concrete is an inorganic alumino-silicate polymer synthesized from predominantly silicon, aluminium and by product materials such as fly ash, GGBS (ground granulated blast furnace slag). Geopolymer concrete does not contain cement. Hybrid fibres were used in this study. Hybrid fibre is the combination of steel fibre and basalt fibre with different volume fractions. When these fibres are added to this special concrete it improves the ductile behaviour and energy absorption capacity. This is due to the property of steel and basalt fibre to bridge the crack development inside the concrete. The main objective of the study is to look into the shear behaviour of hybrid fibre reinforced geopolymer concrete beams.