机电专业英语

硕士研究生《机电专业英语》试题

翻译下列文摘：

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Abstract: The model calculating the instantaneous cutting force is founded on the instantaneous cutting area.In addition,the changing process of the instantaneous cutting force is simulated.It is shown that the axial turning-milling is the process of changed cutting force under the influence of multi-parameters,the instantaneous cutting force of the single gear is a variation in the whole cutting process,and the circumferential edge whose cutting force is much greater than the end edge’s is the main cutting edge.In the whole cutting process,the instantaneous cutting force of the cutter generates two sudden changes.

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Abstract:Introduce the new advances of probabilistic strain fatigue test method,assessment model and the damage random evolution mechanism.Making a breakthrough of the classical maximum likel ihood test method’s single speciment limit outside the refered experiment loads, a general maximum likelihood test method is newly presented.The random cyclic stress-strain responses are found and probabilistic model is established. In addition,a new probabilistic fatigue strain-life model is also developed.These parameters of probabilistic model should be estimated by a so-called general maximum likelihood method in which the effect of scattered regularities of test data and the sample size on the probabilistic model are comprehensivly taken into account on the level of overall data.Resulting from considerations of the random

stress-strain relation deriving into a “random cyc lic strain load” and the random strain-life relation reflecting the material “ cyc lic strain strength”，a cyclic strain load-strength interference model is presented to perform the reliability of constant bining with Keciguliu’s recurrence formula，the amplitude can be changed and the reliability anaiysis under condition of strain load spectrum can be made.All these form a new system which contains the theory and method of strain fatigue reliability.Furthermore,according to the criterion of effectively short fatigue crack,It is revealed that the intrinsic cause of random fatigue properties is the difference

and the evolutionary of the microstructural conditions in the zone of the dominant effectiveiy fatigue crack and tip crack.In addition,the three random fatigue relations of random fatigue crack growth rates,strain-lives,and stress-strain are relative.The fatigue damage is a process from an initial chaotic state to an independent random state，and then to historically related random state.

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Abstract:The orthogonal metal cutting process is analyzed with nonlinear elastic-plastic finite element method under the large general finite element programs.Simulation results show that different tool rake angles have an effect on the cutting shapes,the stress distribution,the strain distribution,the residual stress and the residuai deformation of the workpiece and that the relationship between the rake angle and the shearing angle is analyzed.Validate some experimental results by the way of the simulation, and conclusions can be regarded as the reference on the engineering application.

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