Plastic deformation of the surface layer’s microroughness by a sliding tool with strong contact friction

The plastic deformation of the discrete contacts of a tool with a circular-arc and an inclined profile with the periodical microroughnesses of the metallic part’s surface layer is modeled. The plane deformation theory of a perfectly plastic body is used. The plastic deformation process of the surface layer’s microroughnesses by a sliding tool with Prandtl’s high contact friction in which the plastic shear occurs in the direction of the slide of the tool, with the microroughnesses’ depressions being filled and a decrease of the surface roughness, is studied.     

A highly sensitive field mill for registering weak and strong variations of the electric-field intensity of the Earth’s atmosphere

The design and the principle of operation of an electric-field intensity meter (field mill) are described. The instrument is intended for determining the energy, time, and spatial parameters of the atmospheric electric field near the Earth’s surface when monitoring a geophysical situation. The developed field mill allows registering both weak variations of the electric-field intensity in the atmosphere, such as global electromagnetic Schumann resonances, and strong variations that are caused by the passage of atmospheric fronts, heavy clouds, thunderstorms, etc. The instrument has a threshold sensitivity of ~10^–3 V/(m Hz^1/2) within a frequency range of 10^–3–25 Hz and a wide dynamic range of 120 dB.     

Physical simulation of the action of atomic oxygen and vacuum ultraviolet radiation on polymer materials in the earth’s ionosphere

A procedure of the physical (bench) simulation of the long-term interaction of polymer materials with flows of atomic oxygen and vacuum ultraviolet radiation in the earth’s ionosphere is designed. The efficiency of the bench measurements of mass losses of kapton-H and PM-1E polyimides, polyethylene, and FEP Teflon is confirmed by results of satellite measurements. The dependences of degradation of polymer films on the fluence of atomic oxygen are determined. They allow one to forecast time changes of mass and geometric characteristics of polymers during the whole operating period in the ionosphere. The synergetic effect of the action of the near-satellite environment on the ablation of the polymer films characterizes threshold ratio values of the vacuum ultraviolet energy flow to the atomic oxygen flow.     

More precise determination of the cutting forces at the tool’s rear surface

Two methods have been proposed for more precise determination of the cutting forces when using tools with different wear at the rear surface: in one, the actual contact is taken into account; in the other (proposed by Zorev), it is ignored. In the present work, these methods are compared.     

Experimental methods of determining the cutting forces at the tool’s rear surface

Considerable discrepancies are observed when different methods are used to determine the normal cutting forces at the tool’s rear surface in free right-angled cutting.     

Influence of cutting conditions on the stress at tool’s rear surface

Russian Engineering Research -     

Application of the amended Coriolis flowmeter “bubble theory” to sound propagation and attenuation in aerosols and hydrosols

The existing viscous and incompressible theory of isothermal sound propagation and attenuation in suspensions considers solid particles which are infinitely viscous. We extend the theory by applying the amended Coriolis flowmeter “bubble theory”. Here, the drag force is a function of both the fluid and particle Stokes numbers and the particle-to-fluid ratio of the dynamic viscosity (Galindo and Gerbeth, 1993). Aerosol and hydrosol examples are presented and differences between the original and extended theories are discussed.     

Modeling of surface hardness in hot chamber die casting using Buckingham’s π approach

Hot chamber die casting (HCDC) process is designed to achieve high dimensional accuracy and surface hardness (SH) for industrial applications (like machine tool components). In the present study, outcome of Taguchi model has been used for developing a mathematical model for SH; using Buckingham’s π-theorem for HCDC process. Three input parameters namely pressure at 2^nd phase; metal pouring temperature and die opening time were selected to give output in form of SH. This study will provide main effects of these variables on SH and will shed light on the casting hardness mechanism in HCDC process. The comparison with experimental results will also serve as further validation of model.     

Evaluation of grinding wheel wear in wet profile grinding for the groove of the ball bearing’s inner ring by pneumatic probes

Journal of Mechanical Science and Technology - Wear is one of the most influential factors in profile grinding. The measuring of grinding wheel wear is costly and time consuming. We introduce a new...     

Rate of the tribooxidative and diffusional wear of a tool’s contact surfaces in the machining of metals

The tribooxidative and diffusional fluxes of tool material into the blank are compared. This permits the identification of the dominant type of wear in machining, for different technological conditions.     

Method for graphically evaluating the workpiece’s contour error in non-circular grinding process

To find and compensate the dynamic contour error of workpieces on CNC non-circular grinder, a graphic display and evaluation method is introduced. The programmed set and actual contours of workpiece are displayed through the outlines of grinding wheel at a series of set and actual positions. The dynamic contour error can be recognized directly on CNC control screen without extra measuring equipments as usual. The set and actual positions of grinding wheel related to workpiece are collected from the CNC controller and servo drives and further evaluated. This process is carried out after a dry-run cycle on the machine. Based on this method, a display and evaluation software module has been developed and integrated in the controller of a CNC non-circular grinder. It helps to find contour error and generate the compensation data. Grinding an eccentric test piece shows good result and advantage of the proposed method.     

Effect of micro-scale Young’s modulus and surface roughness on adhesion property to plasma-treated rubber surface

Adhesion between rubbers and metals is often the main cause of machine trouble. Therefore, efficient utilization of rubber in dynamic and static applications requires the modification of the adhesion property of the rubber surface without affecting the bulk characteristics. In this work, we have studied the mechanism of the reduction in adhesion force between medical rubber, chloride-isobutene-isoprene rubber (CIIR), and stainless steel by using surface wave-excited plasma treatment of the rubber surface with oxygen and argon gases. Experimental results showed that surface roughness derivations increased by about 10 times across the treatment, at maximum, corresponding to the increase in time. In addition, the micro-scale Young’s modulus of treated CIIR sheet increased by about 6.3 times at maximum from that of the untreated CIIR sheet. These changes in Young’s modulus and roughness at the surface of CIIR sheet are considered to be the main reasons for the plasma-assisted reduction of adhesion force between stainless steel ball (SUS 440C, JIS) and CIIR sheet.     

Baushinger’s Effect in Wear of Materials

The response of Cu–40%Zn alloy to wear during unidirectional and bidirectional abrasion processes was investigated. It was observed that the mass loss of the alloy decreased as the number of times of changing the sliding direction was increased. Corresponding to this decrease in mass loss, hardness of the worn surface increased initially and then decreased. Cracking in the surface layer was analyzed to get an insight into the mechanism involved. Results of the study suggest that Baushinger’s effect played a role when the sliding direction was alternated.     

Integration of microsensor for microsurgery robot’s end-effector

To enhance the effect of robotic microsurgery, the microsensors are integrated on the robot s end-effector. On the basis of the requirements presented for the integration design, measuring mechanism for the robotic end trephine s force and cutting depth are studied. Force microsensor and position microsensor are used to measure surgical information of the force and depth. Measuring mechanism was achieved by means of linear sliding bearing and differential measuring structure. The sensor data board was developed. With the power spectral estimation of sensor data, two digital filtering methods are proposed, to help eliminate the interference to the original microsensor signal. They are the filtering method of lowpass-bandstop serial structure suitable for a PC, and a shift average filtering algorithm suitable for the sensor data board, respectively. The experimental results show that the integration of microsensors for microsurgery robot s end-effector can satisfy the design requirements, and the robotic end trephine can accurately fulfill the surgical task of corneal cutting.     

Mode for the Development of China＇s Mould Manufacturing Industry in 2008

After China joined into the WTO, the domestic mold industry not only has brought＇impact, but also the opportunity, generally speaking, the opportunity is bigger than the challenge. Why do we say, because, before China＇s accession to WTO, mold import business is basically a tax-free product, domestic mold enterprises for a long time not rely on the protection of non-tariff barriers, the survived enterprises has withstood the test of competition for the early integration of the global economy.     

Detection for transverse corner cracks of steel plates’ surface using wavelet

An algorithm is presented for detecting transverse corner cracks at a steel plate surface using wavelet transform. According to characteristics of transverse corner crack images, the wavelet transform is used for the multi-scale analysis of detecting the image edges and disintegrating the image into four directions at the same time. The proper threshold value is chosen to segment the image into vertical components to obtain the final detection result. The experiment shows that transverse corner cracks of steel plates can be more effectively extracted by the proposed method than the other two common methods.     

Detection for transverse corner cracks of steel plates’ surface using wavelet

An algorithm is presented for detecting transverse corner cracks at a steel plate surface using wavelet transform. According to characteristics of transverse corner crack images, the wavelet transform is used for the multi-scale analysis of detecting the image edges and disintegrating the image into four directions at the same time. The proper threshold value is chosen to segment the image into vertical components to obtain the final detection result. The experiment shows that transverse corner cracks of steel plates can be more effectively extracted by the proposed method than the other two common methods.     

On the thermal aspect of fretting wear—temperature measurement in the subsurface layer

In fretting wear, the kinetics of the oxide film formation as well as the microstructure and the mechanical properties of the subsurface layer depend significantly on the temperature field produced in the fretted zone. Information reported in the open literature indicates contradicting values for the temperature produced at the interface. In the present study, an experimental method for direct measurement of the temperature profile in the subsurface layer has, therefore, been developed and verified. This method overcomes the limitations and the uncertainties inherent in methods of measurement used before. An error analysis indicated that the temperature gradient can be measured within ± 2.5%. The extent of the temperature measurement zone has been estimated by the theory of thermal constriction resistance and found to be in good agreement with some available experimental data.