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1.
1.  The structure of the surface layer exerts a significant influence on the fatigue strength of alloy ÉI437BVD.
2.  The fine-grained structure of the surface layer, which is obtained by the method of mechanothermal treatment, is characterized by the complete absence of macro- and microstresses and possesses high thermal stability.
3.  Mechanothermal treatment of the surface layer of components formed from the heat-resisting alloy ÉI437BVD is an effective method of increasing the fatigue strength and operating reserves of components, which can be recommended for turbine and compressor blades.
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2.
1.  The strength characteristics of the piston alloys under consideration, measured under conditions of isothermal and thermal fatigue approaching those encountered in actual practice, are considerably lower than the static strength characteristics. This indicates the importance of allowing for the factors in question when calculating the strength of interual-combustion-engine pistons.
2.  Of the alloy studied in the present investigation, the lowest thermal-fatigue strength characteristics corresponding to approximately normal working conditions are those of aluminum alloy AL25. For temperature cycles of 55330°C the breaking stress on a base of 2·104 cycles of heat exchangers falls to 1 kgf/mm2, as compared with the isothermal fatigue limit (6.1 kgf/mm2) and the static tensile strength (12 kgf/mm2) at the same temperature.
3.  Under conditions of combined loading, the fatigue life of alloy AL25 falls more rapidly than would follow from the linear hypothesis of damage summation, allowing for both mechanical and thermal fatigue. A vital factor in this case is the damage associated with interaction between the fatigue and thermal fatigue processes due to multiple-factor effects.
4.  Criteria for the failure of piston materials under multiple-factor conditions call for urgent and more extensive investigation.
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3.
1.  With thermal cycling loading for coated specimens microracks occur in brittle coating layers, and conditions for their formation depend not only on coating composition, but also on the composition of the metal being protected, and operating conditions (time, temperature).
2.  Propagation of thermal fatigue microcracks into the basic metal is determined not only by the difference in linear thermal expansion coefficients, elasticity moduli of the coating and basic metal, but it also depends on the thickness of the coating, cycle parameters, aggressivity of the corrosive medium, relative position of the cracks formed, and the level of heterogenetiv for the coating itself.
3.  In order to provide reliable protection for turbine blades from corrosion, coating selection should be carried out with reference to actual operating conditions and the grade taking account of chemical composition) of the basic material.
4.  Numerical evaluation of the features of surface microcrack growth from coatings into the basic metal with thermal cycling loading should be carried out on the basis of threshold aggressivity of the corrosive medium.
I. I. Polzynov Central Institute of Boiler Turbines, Leningrad. Translated from Problemy Prochnosti, No. 12, pp. 30–35, December, 1988.  相似文献   

4.
Abstract and Key Results
▪  In this paper I test the theory that internal capital markets are a motivation for both corporate diversification and vertical integration. I use a sample of 1560 firms from 39 countries.
▪  Using this data I also test theories about vertical integration and capital market development. I also test agency cost and taxation theories of diversification and vertical integration.
▪  I find a significant and negative relationship between corporate diversification and capital market development
▪  I find a significant and positive relationship between vertical integration and capital market development.
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5.
Abstract and Key Results
•  This study discusses the underlying reasons for the variant nature of the relationship between multinationality and firm performance in the context of service firms.
•  To date, this line of research has mostly used evidence from manufacturing firms, despite the ever-increasing contribution of service firms to national and global economies.
•  We conduct an exploratory study using case analyses of large European retail banks. We argue that the nature of the multinationality-performance relationship for services is moderated by industry characteristics, market-based factors and firm-specific factors.
•  We conclude that the shape of the curve depicting the multinationality-performance relationship of retail banks experiences substantial variations on a single case level.
•  Our exploratory study of retail banks shows that the multinationality-performance relationship varies significantly depending on banks’ strategic decisions regarding branch network configurations, product portfolios, branding strategies, organizational architecture (HQ-subsidiary relationship), and social networks. Any generalization of the relationship is difficult and prone to error.
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6.
•  This paper shows that the role of managerial incentives is highlighted by a relatively complex relationship between technological competence and international diversification. By studying a sample of Standard & Poor’s 500 member firms, we explore the relationships between technological competence, managerial pay, and international diversification.
•  Results indicated a curvilinear relationship (an inverted U-shape) between technological competence and international diversification.
•  In line with agency theory, contingent pay (stock options and bonuses) was positively related to international diversification.
•  Beyond these direct effects, both contingent and non-contingent pay (cash compensation) moderated the relationship between technological competence and international diversification.
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7.
1.  The adjustment of parallel and series summing circuits with inductive transducers is exceedingly complex since the adjustment of one transducer affects the other (their sensitivity varies and the zero point can be lost).
2.  Bridge summing circuits offer independent operation and adjustment of all inductive transducers connected in the circuit.
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8.
1.  High-temperature thermomechanical treatment and microalloying with 0.1% La raise the fatigue and corrosion-fatigue strength of steel 1Kh17N2.
2.  The rise in the fatigue strength is due to an increase in the resistance to crack growth resulting from changes in the structure and substructure brought about in the steel by the high-temperature treatment and microalloying with the rare earth metal.
3.  High-temperature thermomechanical treatment of steel 1Kh17N2 and its alloying with 0.1% La raise the corrosion resistance of the steel and reduce its tendency to intercrystalline corrosion.
4.  The increase in the corrosion resistance of steel 1KM7N2 after the high-temperature treatment and microalloying with the rare earth metal is caused by the structural changes produced in the steel by the treatment and the microalloying.
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9.
1.  We proposed a method which can be used to examine the kinetics of failure and cracking resistance of the materials taking into account the type of thermal effect.
2.  The results show that the variation of the temperature conditions during macrocrack propagation has a controlling effect on force and energy characteristics of failure and on the change of the failure micromechanisms. This effect differs for different types of materials.
3.  Electron fractographic examination showed that the level and nature of damage in the material obtained in the previous stage of thermal loading greatly affects the relationships governing the propagation of the macrocrack after a temperature change.
4.  It is shown that it is important to take into account the history of thermal loading (direction and temperature variation amplitude) in determining the cracking resistance of materials and structures.
Institute of Strength Problems, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Problemy Prochnosti, No. 2, pp. 12–16, February, 1989.  相似文献   

10.
1.  Improved strength and working life in sintered hard alloys can be provided by shot blasting under optimal conditions.
2.  One of the major factors governing the improved strength in such treatment is the production of compressive residual stresses in the surface layer.
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11.
1.  The structures of the nodal sections of the dished ends designed in accordance with the compensation principle and design restrictions of the standards are charcterized by the permissable level of the maximum working stresses.
2.  In varying the fraction of the reinforcing metal of the nozzle section situated in the wall of the dished end from 50 to 80% the level of the maximum stresses in the section changes only slightly.
3.  The structures containing 70–80% of reinforcing metal in the wall of the nozzle are more rational from the viewpoint of reducing the metal requirement and have sufficient strength at the same time.
4.  The permissible value of the ratio d/D specified by the standards can be increased from 0.3 to 0.5 without reducing the strength of the nozzle section.
Irkutsk Scientific-Research Institute of Chemical Engineering. Institute of Engineering, Moscow. Translated from Problemy Prochnosti, No. 2, pp. 78–82, February, 1989.  相似文献   

12.
Abstract and Key Results
  After thirty years of research on the relationship between internationalization and firm performance, findings on direction and magnitude are still contradictory. This paper quantitatively reviews prior research in an attempt to reconcile the fragmented results.
  We address the question if and how internationalization relates to firm performance by integrating findings from 36 studies (41 samples, N = 7,792) using the method of meta-analysis.
  We find empirical support for a significant positive relationship at the aggregate level. Equally important, meta-analysis reveals that the relationship is moderated by R&D intensity, product diversification, country of origin, and firm age and size.
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13.
1.  The long-term strength of polygonized aluminum at 100°C depends on the subgrain size and on the dislocation density within the subgrains, while that of the recrystallized metal depends on the grain size: The long-term strength of aluminum increases (at least for lives up to 1000h) with reduction in the grain or subgrain size and with increase in the density of internal dislocations.
2.  The rate of loss of strength (the tangent of the angle of slope of the long-term strength curves) decreases with increase in the grain or subgrain size of aluminum; this leads to the convergence of the long-term strength curves of metal with different subgrains (or grains) at long lives.
3.  An analogy has been found between the behavior of polygonized and recrystallized in long-term strength tests at relatively short times to failure and that in short-term tensile tests.
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14.
•  This paper examines the conditions under which corporate social responsibility (CSR) is related to value creation in the multinational enterprise (MNE).
•  Following prior work by Burke and Logsdon (1996), we examine the relationship of centrality, appropriability, proactivity, visibility, and voluntarism to value creation.
•  The results of a survey of 111 MNEs in Mexico suggest that centrality, visibility, and voluntarism are related to value creation.
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15.
1.  The fracture of heat-resistant alloys and tool steels under the influence of thermal cycling may be quasistatic, fatigue, or mixed in character.
2.  Quasistatic fracture as a result of thermal cycling takes place with the specimen working portion remaining constant (hard loading mode); it is caused by the accumulation of strains of opposite signs in local material volumes.
3.  The accumulation of residual strains in local specimen volumes for thermoplastic strain materials is due to the mismatch of plastic strain fields along the specimens during the heating and cooling cycles.
4.  Under thermal cycling conditions (as in isothermal low-cycle fatigue) the static damage is measured in terms of the accumulated plastic strain (of a given sign), while the fatigue damage is measured in terms of the magnitude of the plastic strain per cycle. Quasistatic fracture takes place in regions of the maximum accumulated plastic strain which is equal to zero in the zone of fatigue fracture.
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16.
1.  As a result of introduction of the system, the possibility of loss of information on the vibration condition of an engine has been eliminated, especiallyin short time appearance of vibrations in failure situations when the vibrations increase very rapidly.
2.  The measuring accuracy has been increased.
3.  Recording of the parameters of vibrations in combination with other parameters characterizing the operation of the engine is provided.
4.  The process of interpreting and treating the test results has been accelerated.
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17.
1.  In the presence of longitudinal cracks of varied length (40–160 mm) and varied amount of elastic energy of the compressed air model (1400–9400 kgf·m) the failure of models on thin-walled shells 0.5 mm thick, when loaded by an internal pressure, has a ductile character, independently of the fitting of transverse tires located at different distances from the crack tip (from 20 to 105 mm).
2.  As the initial length of crack increases, its subcritical growth in thin-walled shells increases linearly.
3.  As the crack length increases, the failure stress (gross) is substantially reduced (from 22 to 9 kgf/mm2). At the same time the character of failure is altered: a straight-line propagation of the crack along the generator of the cylinder is replaced by a curvilinear propagation that approximates the failure direction to the circumferential direction.
4.  With a reduction by a factor of two the amount of elastic energy contained by the compressed air model has almost no effect on the strength and geometrical features of the fracture. A dominant effect on the character of fracture is exerted, apparently, by the magnitude of the failure pressure which alters the relationship of the velocities of propagation of the crack and the waves of elastic unloading.
5.  The limitations on the applicability of the existing calculation methods of the fracture mechanics, for the estimation of the resistance to a ductile failure of thin-walled cylindrical shells, is revealed, and appropriate corrections are proposed.
6.  The effectiveness of the use of transverse tires to stop a started ductile failure of shells loaded by an internal pressure, depends on the distance between the tire and the vertex of the initial crack. This distance leads to a transition from the stoppage of the moving crack to its direction being altered.
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18.
1.  The microstructure of the steel has a strong effect on the resistance to low-cycle fracture. The highest fracture resistance in cyclic loading is shown by the steel with the austenitic structure, that of the steel with the ferritic-pearlitic structure is slightly lower, whereas the lowest resistance was recorded for the steel of the transition grade (ferritic-martensitic). This is explained by special features of deformation of their microstructural components and different properties of the crystal lattice.
2.  In low-cycle loading, the austenitic steel shows susceptibility to hardening, the steel of the ferritic-pearlitic grade is stable, and the steel with the sorbitic and ferritic-martensitic microstructure softens.
3.  The low-cycle deformation resistance of the steels of different structural grades depends on the strength properties in static loading: the resistance is always higher In the material with a higher ultimate strength, i.e., in the steel with a martensitic microstructure.
4.  The microstructure of the steel has the maximum effect in the near-threshold region of the fatigue failure diagram.
Translated from Fiziko-Khimicheskaya Mekhanika Materialov, No. 2, pp. 7–13, March–April, 1992.  相似文献   

19.
•  We explore the role of foreign direct investment and (its relationship to) clusters for the competitiveness (and catching-up) of small(er) developing countries.
•  We suggest that while size per se need not matter, small(er) developing countries need to explicitly account for any liabilities of smallness when devising and implementing strategies for competitiveness and catching-up.
•  We claim that international strategic management scholarship can add insights on this important issue, by complementing extant literature and contributions by international trade and economic development scholarship.

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20.
The theoretical rationale for a multinationality-performance relationship   总被引:9,自引:4,他引:5  
Abstract and Key Results
  This paper reviews the theoretical rationale that has been advanced so far for a positive relationship between multinationality (i.e. international diversification) and performance.
  We show that transaction cost/internalization theory implies no direct and general relationship between international diversification and performance.
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