共查询到20条相似文献,搜索用时 15 毫秒
1.
Based on differential geometry, the contact problems of two surfaces are discussed in this paper. The relationship between the contact status of two surfaces and that of offset surfaces are also analyzed. For a 5-axis NC machining, some research such as optimization of cutter location and calculation of the geometrical cusp height are important. The research results indicate that the relative normal curvature is an important geometrical invariant for describing the contact state of two surfaces. For point contact two surfaces, the calculation equation for the second order remained error is given. For line contact two surfaces, the condition of the second order line contact is that the principal directions and curvatures of the two surfaces are the same along the contact curve. If two surfaces keep the second order line contact, their two offset surfaces will also keep the second order line contact, and their third order remained errors are also uniform with that of the two offset surfaces. 相似文献
2.
A method based on the energy dissipation mechanism of an Independent Oscillator model is used to calculate the frictional
force and the friction coefficient of interfacial friction. The friction work is calculated with considering the potential
change of contact surfaces during sliding. The potential change can be gained by a universal adhesive energy function. The
relationships between frictional force and parameters of a tribo-system, such as surface energy and microstructure of interfacial
material, are set up. The calculation results of the known experimental data denote that the frictional force is nearly proportional
to the surface energy of the material, nearly inversely proportional to the scaling length, and independent of the lattice
constant. The results agree with that of adhesion friction equations. They also agree with the experimental results performed
with an atomic-force microscope under the ultra high vacuum condition.
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Translated from Tribology, 2006, 26(2): 159–162 [译自: 摩擦学学报] 相似文献
3.
Wei LIU Zhenyuan JIA Fuji WANG Yongshun ZHANG Dongming GUO 《Frontiers of Mechanical Engineering in China》2008,3(3):313-317
The geometrical nonlinearity of a giant magnetostrictive thin film (GMF) can be clearly detected under the magnetostriction
effect. Thus, using geometrical linear elastic theory to describe the strain, stress, and constitutive relationship of GMF
is inaccurate. According to nonlinear elastic theory, a nonlinear deformation model of the bimorph GMF is established based
on assumptions that the magnetostriction effect is equivalent to the effect of body force loaded on theGMF.With Taylor seriesmethod,
the numerical solution is deduced. Experiments on TbDyFe/Polyimide (PI)/SmFe and TbDyFe/Cu/SmFe are then conducted to verify
the proposed model, respectively. Results indicate that the nonlinear deflection curve model is in good conformity with the
experimental data.
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Translated from Journal of Dalian University of Technology, 2007, 47(1): 34–38 [译自: 大连理工大学学报] 相似文献
4.
To precisely implement the force control of robot manipulators in an unknown environment, a control strategy based on fuzzy
prediction of the reference trajectory in the impedance model is developed. The force tracking experiments are executed in
an open-architecture control system with different tracking velocities, different desired forces, different contact stiffnesses
and different surface figurations. The corresponding force control results are compared and analyzed. The influences of unknown
parameters of the environment on the contact force are analyzed based on experimental data, and the tunings of predictive
scale factors are illustrated. The experimental results show that the desired trajectory in the impedance model is predicted
exactly and rapidly in the cases that the contact surface is unknown, the contact stiffness changes, and the fuzzy force control
algorithm has high adaptability to the unknown environment.
Translated from Journal of Northeastern University (Natural Science), 2005, 26(8): 766–769 [译自: 东北大学学报 (自然科学版)] 相似文献
5.
Chen Yangzhi Xing Guangquan Peng Xuefei Liu Wenguang Yao Huaping 《Frontiers of Mechanical Engineering in China》2007,2(1):94-98
The volume of an in-tube micro robot is small and its interior space is very limited. However, conventional transmission methods
are unfit to drive in-tube micro robots. A novel micro drive mechanism called the micro-elastic-meshing-wheel is presented
in this paper. It can be used for transmitting power and locomotion between two shafts, which are upright and cross in a micro
space. The mechanical model of the novel drive mechanism is built, and the maximal transmission force is deduced. Then, sufficient
experiments are carried out to test maximal transmission force produced by the novel drive mechanism. The calculation and
experiment results show that the novel drive mechanism can transmit sufficient power to in-tube micro robots.
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Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(7): 45–49 [译自: 华南理工大学学报 (自然科学版)] 相似文献
6.
Zhongming Xu Lingyun Ding Ping Huang 《Frontiers of Mechanical Engineering in China》2008,3(3):276-282
An interfacial potential barrier theory to calculate friction and wear is proposed by considering the micro interaction of
frictional surfaces. The theory suggests that the performance of friction and wear depends on the magnitude and distribution
of the interfacial potential barrier on contact surfaces. The calculation methods of the interfacial potential barrier and
standard interfacial potential barrier are then studied and the formulas to calculate the friction force, friction coefficient,
and quantity of adhesion wear are derived based on the theory. With its independence and stability, the standard interfacial
potential barrier can be used as an index to describe the frictional performance of materials. The calculation results of
the friction force with some existing experimental data are consistent with the experimental results performed with an ultra
high vacuum atomic-force microscope, which proves that the theory and method are feasible.
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Translated from Tribology, 2007, 27(1): 54–59 [译自: 摩擦学学报] 相似文献
7.
Fei Yanqiong Dong Qinglei Zhao Xifang 《Frontiers of Mechanical Engineering in China》2007,2(1):116-119
This paper proposes a novel, hermaphroditic, and lattice self-reconfigurable modular robot. Each module is composed of a center
body—a cubic part and six sides that can rotate independently. There are two holes and two extensible pegs on each side. The
rotary motion of each side and the extensible motion of the pegs are generated by a motor connected to a reducer, using a
cone-shaped gear, belt, clutch, etc. The structure of the module is compact, and has space to extend further.
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Translated from Journal of Shanghai Jiaotong University, 2005, 39(6): 877–879 [译自: 上海交通大学学报] 相似文献
8.
Liu Xiancui Su Lanhai Li Zhongfu Fu Zhilin Zhang Qingdong He Chun 《Frontiers of Mechanical Engineering in China》2007,2(3):297-300
Research into plate elongation distribution between the tension leveler and temper mill for pickling line 2030 at Baosteel
is conducted. The study, which involved performance testing of mechanics, is designed at different elongation distributions
and analyzed from many aspects. Finally, the optimal elongation of the tension leveler and temper mill is given.
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Translated from Journal of University of Science and Technology Beijing, 2005, 27(5): 609–612 [译自: 北京科技大学学报] 相似文献
9.
A three-dimensional contact analysis was conducted to investigate the contact behavior of elastic--perfectly plastic solids with non-Gaussian rough surfaces. The effect of skewness, kurtosis and hardness on contact statistics and the effect of skewness and kurtosis on subsurface stress are studied. Non-Gaussian rough surfaces are generated by the computer with skewness, Sk, of −0.3, 0.0 and 0.3, and kurtosis, K, of 2.0, 3.0 and 4.0. Contact pressures and subsurface stresses are obtained by contact analysis of a semi-infinite solid based on the use of influence functions and patch solutions. Variation of fractional elastic/plastic contact area, maximum contact pressure and interplanar separation as a function of applied load were studied at different values of skewness and kurtosis. Contact pressure profiles, von Mises stresses, tensile and shear stress contours as a function of friction coefficient were also calculated for surfaces with different skewness and kurtosis. In this study, it is observed that surfaces with Sk = 0.3 and K = 4 in the six surfaces considered have a minimum contact area and maximum interplanar separation, which may provide low friction and stiction. The critical material hardness is defined as the hardness at which severe level of plastic asperity deformation corresponding to the Greenwood and Williamson’s cut-off A
plastic/A
real = 0.02 occurs for a given surface and load condition. The critical material hardness of surfaces with Sk = 0.3 and K = 4 is higher than that of other surfaces considered. 相似文献
10.
Wang Zhaoxia Zhang Weimin Liu Hongguang 《Frontiers of Mechanical Engineering in China》2008,3(2):222-225
The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled
according to the magnetic dipole theory. The formula to compute the normal component of the weak magnetic field is deduced
based on the spatial distribution of the magnetic dipole. The shape and characteristics of the zero line (an important criterion
for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations. Results show that
the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and
locate the defect.
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Translated from Transactions of Beijing Institute of Technology, 2007, 27(147): 395–398 [译自: 北京理工大学学报] 相似文献
11.
Li Zhinong He Yongyong Chu Fulei Wu Zhaotong 《Frontiers of Mechanical Engineering in China》2007,2(1):46-49
A blind identification method was developed for the threshold auto-regressive (TAR) model. The method had good identification
accuracy and rapid convergence, especially for higher order systems. The proposed method was then combined with the hidden
Markov model (HMM) to determine the auto-regressive (AR) coefficients for each interval used for feature extraction, with
the HMM as a classifier. The fault diagnoses during the speed-up and speed-down processes for rotating machinery have been
successfully completed. The result of the experiment shows that the proposed method is practical and effective.
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Translated from Journal of Tsinghua University (Science and Technology), 2005, 45(8): 1 036–1 039 [译自: 清华大学学报(自然科学版)] 相似文献
12.
Yinnan Yuan Deqing Mei Zhong Wang Tian Zhang 《Frontiers of Mechanical Engineering in China》2008,3(2):189-192
The combustion and heat release of engines using diesel fuel and bio-diesel fuel have been investigated. The results illustrate
that the combustion happens in advance and the ignition delay period is shortened. The initial heat release peak declines
a little, the corresponding crankshaft angle changes in advance, and the combustion duration is prolonged. The economic performance
and emission features of diesel engines using diesel fuel and bio-diesel fuel are compared. The results also show that the
specific fuel consumption of bio-diesel increases by about 12%. The emissions, such as CO, HC, and particulate matter decrease
remarkably whereas NO
x
increases a little.
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Translated from Journal of Jiangsu University (Natural Science Edition), 2006, 27(3): 216–219 [译自: 江苏大学学报(自然科学版)] 相似文献
13.
Tao SHANG Dingxuan ZHAO Yuankun ZHANG Xiangen GUO Xiangzhong SHI 《Frontiers of Mechanical Engineering in China》2008,3(1):86-90
To enhance the performance of a hydrodynamic torque converter and thoroughly understand the trait of inside flow, a numerical
simulation method of internal 3D flow for the three-element centrifugal hydrodynamic torque converter was systematically researched
and expatiated in this paper. First, the internal flow field of each impeller was calculated. The curves that illustrate the
relationships between the pressure differences of the inlet and outlet versus flux were drawn. Second, the concurrent working
point of each impeller was approximately estimated. Finally, a calculation was performed considering the influence on each
impeller. The flow field of a working point was solved by multiple calculations and the actual working condition was gradually
determined. The pressure and velocity distributions of the flow field were proposed. The performance parameters of the hydrodynamic
torque converter were predicted. The calculation method, and the proposed pressure and velocity distribution of the flow field,
have practical significance for the design and improvement of a hydrodynamic torque converter.
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Translated from Journal of Jilin University (Engineering and Technology Edition), 2006, 36(2): 199–203[译自: 吉林大学学报(工学版)] 相似文献
14.
A dynamical sliding-mode controller is devised to track the output of mobile manipulators. During the investigation, firstly
a reduced dynamic model considering the dynamics of the driving motor is developed for mobile manipulators. Then, the system
is decomposed into four lower-dimensional subsystems by means of diffeomorphism and nonlinear input transformation. Moreover,
a design method of the dynamical sliding-mode controller that is applied to the output tracking of mobile manipulators is
proposed. The simulation results indicate that the dynamical sliding-mode controller can not only track the given trajectory
correctly but also reduce the chattering of sliding-mode control system considerably.
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Translated from Journal of South China University of Technology (Natural Science Edition), 2006, 34(6): 29–33 [译自: 华南理工大学学报 (自然科学版)] 相似文献
15.
Zhanshe GUO Yihui WU Yonggang MENG Dezhi ZHENG 《Frontiers of Mechanical Engineering in China》2008,3(1):76-80
To satisfy the needs of the high deep-width ratio and thickness of a planar micromotor’s stator windings, a process method
to produce an electromagnetic planar micromotor with AZ4903 is proposed. Optimum relationships, such as the desired rotation
speed vs. thickness of the coating process, and the temperature vs. time of pre-baking, are obtained. The appropriate time
of lithography and development are also achieved. The thickness of the produced windings is 40 μm with ideal perpendicularity.
Finally, stators and rotors are fabricated. The rotation speed and pull-out torque of the micromotor are tested. The experiment
proved that the micromotor worked with a steady speed and a low ripple of pull-out torque.
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Translated from J Tsinghua Univ (Sci & Tech) 2005, 45(8): 1062–1065 [译自: 清华大学学报(自然科学版)] 相似文献
16.
An energy reclaiming suspension is proposed to reclaim vibration energy in the suspension. To study its riding performance
and reclaiming energy performance, a hydraulic energy reclaiming device prototype is produced and its mechanical behavior
is analyzed and tested according to the hydraulic theory. Theoretical analysis shows that mechanical behavior of the energy
reclaiming device is embodied by a viscidity damping parameter and an analogous coulomb damping parameter determined by its
structure; their expressions are obtained. Experimental investigation shows that theoretical predictions agree with test results.
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Translated from Journal of Jiangsu University (Natural Science Edition), 2006, 27(1): 35–39 [译自: 江苏大学学报(自然科学版)] 相似文献
17.
Yituan He Chaochen Ma Mingshan Wei Zhifu Zhu 《Frontiers of Mechanical Engineering in China》2008,3(2):218-221
To study the performance of high and low stage compressors and that of the system as a whole, a two-stage turbocharging system
was matched, and a special two-stage turbocharging system test bench was built. For each test curve, the speeds of the two
stage turbochargers were adjusted to the fixed data, and a compressor performance experiment was performed. The results showed
many differences between the corrected mass flow and the actual mass flow of the high pressure (HP) stage compressor. To find
out the actual supercharging effect of the two-stage turbocharging system, it is better to adopt the actual mass flow. The
two-stage turbocharging system in this paper has much higher efficiency under most operating conditions if the pressure ratio
assignment is 1:1. The system can get very high supercharging pressure when the speeds of the two stage turbochargers are
rather low, which ensures the system’s security and reliability.
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Translated from Transactions of Beijing Institute of Technology, 2007, 27(6): 496–500 [译自: 北京理工大学学报] 相似文献
18.
Effects on mechanical properties in electron beam welding of TC4 alloy by laser shock processing 总被引:1,自引:0,他引:1
Lu Jinzhong Zhang Yongkang Kong Dejun Ren Xudong Ge Tao Zou Shikun 《Frontiers of Mechanical Engineering in China》2007,2(4):478-482
The surface of TC4 titanium alloy welding line by electron beam welding (EBW) was processed by high power Q-switched and repetition-rate
Nd: glass laser. Effects of laser power and spot diameter on residual stress and microhardness of the TC4 alloy welding line
by laser shock processing (LSP) have been analyzed. Results show that residual stresses almost do not change as laser power
is 45.9 J, spot diameter is ϕ9 mm; While laser power is 45.9 J, spot diameter less than ϕ3 mm, the distribution of residual
stress in welding line occurs obvious variation, which residual stress increase obviously with spot diameter decrease. When
power density is bigger than 1.8 × 1010 W/cm2, residual stresses of electron beam welding line occur change by LSP, which improve obviously residual stress distribution;
while laser power is bigger than 1.2 × 1010 W/cm2, the surface micro-hardness of electron beam welding line occurs change by LSP, which improve obviously micro-hardness distribution.
Mechanical properties of TC4 titanium alloy welding line will be improved by LSP, which provides experimental foundation for
further controlling the distributions of residual stress and micro-hardness during laser shock processing.
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Translated from Journal of Jiangsu University (Natural Science), 2006, 27(3): 207–210 [译自: 江苏大学学报 (自然科学版)] 相似文献
19.
Zhang Jianming Zhang Weigang Yang Bing Wang Yawei 《Frontiers of Mechanical Engineering in China》2007,2(4):439-441
A force model of a control valve of injector is set up, and the changes of the fluid damping clearance are investigated on
the basis of the results of the computational fluid dynamics (CFD) and the experiments of control valve of injector. Results
indicate that a damping clearance of 0.02–0.03 mm between the poppet and the valve guide is the most sufficient to dampen
any excessive control valve poppet bouncing.
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Translated from Journal of Shanghai Jiaotong University, 2006, 40(6): 1031–1034 [译自: 上海交通大学学报] 相似文献
20.
Fengwei HUO Zhuji JIN Renke KANG Dongming GUO Chun YANG 《Frontiers of Mechanical Engineering in China》2008,3(3):325-331
The accurate evaluation of grinding wheel surface topography, which is necessary for the investigation of the grinding principle,
optimism, modeling, and simulation of a grinding process, significantly depends on the accurate recognition of abrasive grains
from the measured wheel surface. A detailed analysis of the grain size distribution characteristics and grain profile wavelength
of the fine diamond grinding wheel used for ultra-precision grinding is presented. The requirements of the spatial sampling
interval and sampling area for instruments to measure the surface topography of a diamond grinding wheel are discussed. To
recognize diamond grains, digital filtering is used to eliminate the high frequency disturbance from the measured 3D digital
surface of the grinding wheel, the geometric features of diamond grains are then extracted from the filtered 3D digital surface,
and a method based on the grain profile frequency characteristics, diamond grain curvature, and distance between two adjacent
diamond grains is proposed. A 3D surface profiler based on scanning white light interferometry is used to measure the 3D surface
topography of a #3000 mesh resin bonded diamond grinding wheel, and the diamond grains are then recognized from the 3D digital
surface. The experimental result shows that the proposed method is reasonable and effective.
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Translated from Journal of Dalian University of Technology, 2007, 47(3): 358–362 [译自: 大连理工大学学报] 相似文献