Search results

It is possible to classify the concrete materials as a function of its main characteristics, in special the contribution of mechanical, physical, and chemical aspects in material properties.
However, the type and extension of the hydration process and alkali-silica reactions affect significantly the concrete porosity and, consequently, its permeability and durability.
The concrete quality must be to guarantee resistance against the combination of environmental factors and mechanical loading [7-11].
In addition, the use of metallic slag aggregates aiming the insertion of coarse aggregates has shown any negative effects on the structural properties of hardened concretes [22].
Monteiro: Concrete: Microstructure, Properties and Materials.

The disturbances can significantly affect the precision of tracking servo.
One of the major issues associated with the design of a tracking servo controller is the fact that some disturbances have unknown and possibly time varying properties.
The closed loop system performance variable is then given by: Consider the parameter as , where ,, and is a weighted function used to adjust the dynamic properties of .
In the case where the disturbance input properties are unknown and possibly time varying, it is desired to introduce adaptation in the controller design process.
Let ; ; Define and the modified error: (8) The recursive least squares algorithm with a time varying forgetting factor can be given as follows: (9) with , and where is a time varying forgetting factor satisfying .

Because of many links and joints, the static stiffness model of parallel robot needs to consider lots of factors, such as the influence of deformation of links, joints and drive units, and gravity of all the parts, the static stiffness of parallel robot is very complicate, it is related to branch type, mechanism configuration, structural parameters and location parameters, etc.[3].
As the gravity of moving platform and branches have little to do with the static stiffness of parallel robot [3], we ignore the gravity factors.
Modify and simplify the three-dimensional solid model to enable them to meet the requirements of ANSYS, which not only does not affect accuracy, but also save a lot of time, avoiding the waste of resources.
The element type is selected for Solid92, defining the material properties and meshing, 1043832 nodes and 658380 elements were meshed (Fig.4).
Mechanical Design. 27 (2010) 1-4

Its performance directly affects the safety running for switch apparatus, playing an important role in the service life of electrical appliance as well as reliability and security.
Contact erosion, according to its reason of formation can be divided into mechanical erosion, chemical corrosion and electrical erosion.
Usually, the erosion of anode or cathode contacts is different because of the two contactor material’s different physical properties, or the different amount of the input arc energy and heat-flow density when the circuit turn on or turn off.
Contacts surface morphology, under the influence of many factors, such as mechanical impact, arcing and electron or ion bombardment, are bound to change.
Project(No.u0837601) supported by the National Nature Science Foundation of China References [1] Zhou Maoxiang , Low Voltage Electrical Design Manual, Mechanical Industry Press, Beijing, 1992

Lorini 1,c 1 Federal University of Rio Grande do Sul (UFRGS), Mechanical Engineering Department (DEMEC), Porto Alegre, RS, Brazil.
The roughness surface generated through turning process is affected by the conditions of machine-tool, workpiece, tool clamping and mainly by feed rate f [mm/rev] and nose radius rε [mm] of the cutting tool.
In general, surface integrity can be divided into two aspects: the external topography of surfaces (surface finish); and the microstructure, mechanical properties and residual stresses of internal subsurface layers [6].
There are some factors that may contribute to generate roughness, such as: grooves generated by the tool nose; burr generation on the workpiece during the cutting operation; bits of the built-up edge in the machined surface; geometric shape of the chip breaker on the tool edge [3].
Dissertation, Mechanical Engineering Department, Georgia Institute of Technology, 2006, 170p

All these factors influence the resistivity in the martensite and austenite phases.
As the martensitic transformation is base for the unusual functional properties in TiNi alloy, then the shape memory effects must be affected by the same irradiation parameters as phase transition.
Ito et al., Effect of neutron irradiation on the transformation and mechanical properties in Ti-Ni shape memory alloys, J.
Ohnuki et al., Microstructure and mechanical properties of neutron irradiated TiNi shape memory alloy, J.
Gadaskin, Influence of reactor irradiation on structure, mechanical properties and shape memory effect in TiNi, Questions of atomic science and techniques.

It can affect the stability of the black rocks themselves and other non-black rocks nearby directly, and cause engineering and environmental geological problems.
It would lead to the changes of the chemical composition of groundwater and rock properties.
And then the vitriol materials and clay minerals which are subsequently dissolved away by surface water and groundwater, causing the destruction of rock mass structure and the decrease in mechanical properties
(3) Regarding engineering properties of corrosive acidic water formation in black rock under water-rock reaction, from the factor of controlling acidic water, methods such as adding additives, the use of phosphatides complexation and the use of limestone buffer layer can be applied to reduce the oxidation of pyrite or to neutralize the acidic water in black rock, and thus the damage caused by water-rock reaction within black rock can be prevented
Weathering degree and properties of Doushantuo group black rock in the west of Hunan Province[J].

Mobility Analysis of Power Flow through the Half Shaft System of the Turntable Qiuhong Lia, Kai Xueb, Yan Lic, Tao Qind College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin 150001, China aliqiuhong@hrbeu.edu.cn, b xuekai@hrbeu.edu.cn, cliyan500002@126.com, d dhrbeu_qintao@126.com, Keywords: admittance matrix; power flow; vibration analysis Abstract.
The technology lays foundation on the vibration property of the turntable structure for the further research.
(10) In which is the stiffness matrix, is the damping matrix, is the damping ration factor
Fig. 6 Test platform system Fig. 7 Test platform result The expectation deviates from the experimental results for the experimental error, but it was considered that the affect can be ignored.
After analyzing the structure property of the established optimization problem, the method reflected the dynamic characteristics of every subsystem.

Heat Conduction Structural Topology Optimization Based on RAMP Jiachun Li1, a, Wente Tu1, a, Xudong Yang1, a, Jian Fu1, a, Yongtao Wang1, a 1 College of Mechanical Engineering, Guizhou University, China aljcgd211@163.com Keywords: heat conduction； topology optimization； Optimization Criteria；filtering technique Abstract.
Some numerical examples are presented to demonstrate the capability of the method presented herein. 2 Structural Topology Optimization Model Based RAMP 2.1 RAMP Interpolation Approach In this approach, the simple relationship of relative material density and effective property tensors are assumed as follows, （1） Wheredenotes property tensor of intermediate densities elements, the difference between property tensors of solid material and void material satisfying <20.
Introducing damping factor to ensure the computational stability and convergence, usually=0.5.
References [1] S.Xu, R.V.Grandhi, Structural Optimisation with Thermal and Mechanical Constraints, AIAA J.
Chinese Journal of Mechanical Engineering, 2003, 39(11):47～51(in Chinese)

Introduction Metastable (Ti,Al)N ternary solid solution coating of B1 structure has been successfully developed as wear-resistance and anti-corrosion coating material for more than two decades due to its superior oxidation-resistance and mechanical properties [1-3].
In order to further improve the properties, especially oxidation-resistance and anti-wear performance, quaternary (Ti,Al,X)N coatings were developed by introducing element X into (Ti,Al)N.
Besides the composition, the process parameters of physics vapor deposition (PVD) play important roles to determine the structure and property of the coatings.
Various factors such as the texture orientation, stress state, crystlline size solid solution strengthening and crystal defect affect the hardness of (Ti,Al,Nb)N.