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691.
W. Hong C. Choi W. Lee J. P. Hong D. Kum 《International Journal of Automotive Technology》2009,10(4):489-495
This paper proposes an advanced permanent magnet (PM) motor drive modeling for dynamic analysis of automotive control systems
with PM motor drives. To enhance the reusability of the proposed PM motor drive model, each component is modeled in an object-oriented
manner according to the physical partitioning of a real drive system, and userfriendly and well-organized interfaces are also
proposed. These characteristics enable this model to be used as a kind of a programming library. A multi-level modeling strategy
is also proposed, which helps make a compromise between model accuracy and simulation speed without structural modification
of the system model. The model and modeling strategy developed allow for a comprehensive analysis of each component and dynamic
analysis of the total system. System simulation results show the practical effectiveness of the proposed modeling strategy. 相似文献
692.
H. W. Lee S. H. Park M. W. Park N. G. Park 《International Journal of Automotive Technology》2009,10(4):459-467
A mathematical model of an automotive transmission is developed, that considers the flexibility of the shafts, bearings, and
gear teeth, and gyroscopic effects of geared rotors. The transverse, torsional, and axial motions are strongly coupled due
to helical gearing. The excitation forces acting on the automotive transmission are classified into first, second, and third
grades, based on the magnitudes of the forces that are determined by the perturbation method. The excitation forces are caused
by the mass imbalances among gears, misalignment of shafts, clearance and non-linear deformation of bearings, transmission
errors, and the periodic variation of the gear mesh stiffness. A bench test on loading conditions is carried out for the third
speed of the automotive transmission. The experimental results of vibration characteristics are compared with those from theoretical
analysis. The results show good agreement, i.e., within a tolerance of 3.3%. 相似文献
693.
联络通道冻结法施工三维力学分析 总被引:1,自引:0,他引:1
应用人工冻结土体技术开挖隧道的联络通道,涉及到土体冻结的热力学作用以及冰冻土体与隧道结构相互影响等一系列复杂的物理力学过程。采用FLAC3D建立主隧道、联络通道及冻结管的三维数值模型,综合考虑了温度计算、冻土与非冻土的转变及土体的冻胀作用,研究了人工冻结法对隧道管片及周围土体的力学响应。通过对冻胀率参数敏感度分析,研究土体冻结变形、冻胀力及隧道管片内力的变化,所得到的初步结果对冻结法施工有着实际的工程意义。 相似文献
694.
The vibrational characteristics of automotives during idling were studied experimentally by considering the axial forces of
the drive shaft and the spider positions in a constant-velocity joint. The generated forces, such as PF (plunging force) and
GAF (generated axial force) in the assembly of the drive-shaft module, were measured directly by an experimental apparatus.
Measurements of the GAF and PF did not show the same trends as the joint angles. They depended instead on the types of CV
joints. In addition, the relationship between the offset values of the shaft and the spider positions in the tulip of the
constant-velocity joint were studied. As a result, the idle vibration characteristics were affected by the variation of the
spider positions and the vibrational characteristics in the axial direction of the shaft, including the amplitude and the
harmonic periods. 相似文献
695.
S. -S. Cho C. S. Shin C. S. Lee H. Chang K. W. Lee 《International Journal of Automotive Technology》2010,11(1):75-80
An engine cylinder head-block joint is a gasketed, bolted joint. Assessment of sealing performance and fatigue durability
of the joint during engine development relies entirely on the engine dynamometer test because the rig test cannot mimic the
engine run condition and finite element analysis employs gasket and bolt models that are too simple to provide the stress
data for fatigue assessment. This paper introduces finite element-based assessment of the gasket and the bolt and a model
that improves the analysis accuracy without increasing computation time. Experimental data for the deformation of joint members
under thermo-mehanical load are presented to demonstrate the accuracy of the model. 相似文献
696.
Defects such as porosity, underfill, and magnesium loss occur during laser welding of 5182 aluminum alloy. To compensate for these problems, AA5356 filler wire was used in our present work. To investigate the weld characteristics of the filler wire, experiments were performed with laser power, welding speed, and wire feed rate as the control variables. Bead appearance, bead shape, penetration depth, tensile strength, and the Erichsen ratio were observed as weld characteristic variables. The range of full penetration was reduced as laser power decreased and welding speed and wire feed rate increased. Without filler wire, full penetration was formed under all conditions. However, with filler wire, the range of conditions necessary to form full penetration was reduced as the wire feed rate increased because the heat input was used to melt both of the filler wire and the base metal. Filler wire increased the tensile strength and the Erichsen ratio. Using analysis of variance (ANOVA), it was shown that laser power had a greater influence on tensile strength and the Erichsen ratio among the three control variables. It was also found that tensile strength was closely related to the Erichsen ratio because the coefficient of correlation was 0.899. 相似文献
697.
Although counteracting environmental programmes and policies have been strengthened, large oil spills still occur at irregular intervals. The total oil spill costs and their compensations have attracted much interest from various parties, such as local stakeholders, and state and federal governments. This paper addresses five major cost categories whose aggregations are expected to cover the overall direct and indirect costs after the release of an oil spill. Among them, research costs should not be neglected, since they tend to be high if public attention has been drawn to the case. Through an examination of the relationship between the total oil spill costs and their admissible claims, we found that:
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admissible claims do not cover the overall costs of the oil spill, and
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admissible claims cannot be compensated in full in the case of large spills.
698.
699.
700.
S. Tousi A.K. Bajaj W. Soedel 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1992,21(1):333-360
This work focuses on the interaction between a driver and a car-trailer combination. A model characterizing human operator behavior in regulation task is employed to study directional stability of the overall system. The vehicle-trailer model retains nonlinear cornering force and other kinematic nonlinearities. Linear stability of the straight line motion is analyzed by the application of Routh-Hurwitz criteria and stability boundaries in parameter space are constructed by setting appropriate Hurwitz determinant to zero. It is shown that two types of transition in stability are possible in the driver/car-trailer system. They correspond to one pair or two pairs of complex conjugate eigenvalues crossing the imaginary axis simultaneously. The implications in terms of resulting motions for the nonlinear system are also discussed. It is shown that stabilization of the combination can be achieved by adding a passive controller at the articulation point. Articulation damper turns out to be a more useful device for controlling trailer oscillations instability although a combination of damper and torsional spring would be a more ideal solution. 相似文献