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Sandwich composite laminates have excellent mechanical properties, which present great application potential.
Sometimes, small damage is even invisible, but residual strength after damage is affected greatly.
Regarding low velocity impact problems, Hosur[2] investigated impact properties of a foam filled 3-D integrated core sandwich composite laminates, and analyzed impact load-time-energy history curve in detail.
The damage processes and factors which effect residual strength were analyzed.
Experimental Investigation of the Impact Mechanical Properties of Polyurethane Rigid (PUR) Foam Plastics [J].

The global and local stress intensity factors for finite kinked cracks, the stress intensity factors for finite transverse cracks, and the Paris law for fatigue crack propagation are used.
The global and local stress intensity factors for kinked cracks, the stress intensity factors for transverse cracks, and the Paris law for fatigue crack propagation are utilized in the model.
The accurate global and local stress intensity factors for finite kinked cracks in Lin et al. [8,9], the stress intensity factors for finite transverse cracks in Tada et al.[14], and the Paris law for fatigue crack propagation are utilized in the model.
Burford, Factors Affecting the Properties of Swept Friction Stir Welds, SAE Technical Paper, Society of Automotive Engineers, Detroit, (2008) 14-17
Pan, Stress Intensity Factors for Spot Welds and Associated Kinked Cracks in Cup Specimens, International Journal of Fatigue (2005) 81-98

Improvement in small size and mechanical, electronic and functionality achievement is needed with the growth of telecommunications industry.
Solder alloy materials have high melting points thus making their mechanical properties to be less affected by temperature.
The material properties for the Sn-3.9Ag-0.6Cu solder alloy that satisfies the BISO model is listed in Table 3.A single ball 3-dimensional elastic-plastic model were used to examine the effects of shear speed with fixed shear height on the failure behavior of the single solder joint ball.
Table 2 .Linear Elastic Material Properties For BGA Assemblies Materials Young’s modulus (GPa) Poisson’s ratio Density (kg/m3) Sn-3.9Ag-0.6Cu 52 0.35 7500 Cu 117 0.34 8900 FR4 172 0.39 1900 Fig1.
Thus, this concludes that increase in shear force by increasing the shear speed is an absolute outcome of the solder material properties such as time-independent plastic hardening and time-dependent strain-rate sensitivity.

The reason is that, after severe deformation, there will be various strengthening modes, such as slip, mechanical twinning and shear banding which affect the distribution of internal stress within crystals of face-centered-cubic (f.c.c.) materials [5].
Samples σ0.2 (Mpa) σb (Mpa) εu (%) εe (%) Before annealing 710.79 748.27 1.72 3.08 Annealing at 200℃ 873.93 914.34 1.67 2.00 Annealing at 250℃ 747.49 796.11 1.76 2.84 Table 1 shows the tensile properties of the specimens annealed at different temperatures.
So the fine-grain strengthening and the micro-stain closely related annealing twins are not the major factors that induce the anomalous hardening in cold-rolled copper alloys.
Wang, Enhancement of mechanical properties of heat-resistant martensitic steel processed by equal channel angular pressing, Mater Sci.
Lu, Microstructure evolution and thermal properties in nanocrystalline Fe during mechanical attrition, Acta Mater. 49 (2001) 365-375

There are several factors that affect the wear-life of SPB, such as load, frequency of oscillation, amplitude of oscillation, physical dimension, materials, manufacturing quality, working environment and lubrication.
The factors that affected the wear-life of SPB were all obtained by life test instead of mechanism analysis, and it could not satisfy the demand of calculating the wear-life accurately and reliability research for SPB.
m, τ are the surface pressure and sliding velocity exponential factors to wear rate.
It depended on the load and mechanical property of the materials of the ACSPB, and can be got through contact mechanics method [8].
H is the limiting wear intensity; P is the load (radial load Pr or axial load Pa); n is the oscillation velocity (unit: rad/s). 2) The models in this paper had considered most of the factors contributed to the wear-life of SPB, including configuration parameters(R, θ1, θ2, α0), working parameters(P, n), material and working condition factors (K) and the function requirement (H).

Introduction Because of their excellent mechanical properties and good biocompatibility, ceramic balls for total hip replacements (THR) have been widely used [1].
The taper-bore contact length H, as defined in Fig. 2, is important, which affects the stress distribution and mechanical reliability of a ceramic femoral head.
The interfacial characteristics such as friction is another factor which influences load transmission, and hence the stresses in a ceramic femoral head.
When the friction coefficient at this interface reaches 0.35, maximum tensile stress along the taper interface reduces by a factor of eight.
Of the Institution of Mechanical Engineers [H], Vol. 214 (2000), p.685 [11] G.

The purpose was to perform local alloying in the form of surface network of four tracks (each two are parallel and perpendicular to the other two) to produce a good thermal and electrical properties bulk material with reasonable surface hardness properties.
The morphological features of the subsurface laser treated layers and their mechanical properties (microhardness) have been studied on oblique sections through the laser fused tracks.
Laser treatment improves the surface properties of materials in many ways.
Better properties can be achieved such as hardness, heat stability and wear resistance.
However, the results of these experiments showed no improving in cutting properties [2].

Because of multiple constructions, the ground roughness, adhesion, permeability resistance, wear resistance are greatly affected [2].
When the dosage is not enough, the flow properties of concrete can not reach the specifications [3].
Thereby the density and uniformity will be affected, and ultimately the mechanical properties and durability damage.
And the mortar surface quality is affected seriously by the laitance and floating dust.
When water consumption changed while other factors remained, the maximum of the mortar strength appeared.

Introduction Zn-5wt%Al alloy has been widely applied because of superior properties[1-3].
Because physical properties varied with temperature and so forth, the critical withdrawal rate of Zn-5wt%Al alloy was only calculated approximately.
Because of change of exterior and interior factors, the liquid/solid interface during solidification takes on much pattern.
From literature [9], the superheat of metal melt affected the pattern of liquid/solid interface during solidification.
The two factor competed each other.

The air temperature is the major factor affecting built-in basic temperature.
Table 5 Thermophysical properties of cement concrete pavement Structure Thermal conductivity [W/m.
The temperature difference through the slab thickness was recognized as built-in temperature difference during the final setting time which is assumed to be the moment when stiffness properties begin to develop in the JPCP.
Based on the basic properties of BITD of JPCP constructed in different periods in Fuzhou region, it can be seen that BITD of pavement constructed in hot summer has maximum BITD and basic temperature.
The decrease of climate effect factors may lead to the reduction of negative BITD variation