Analysis of Gear Wheel-shaft Joint Characterized by Comparable Pitch Diameter and Mounting Diameter

This paper presents the design procedure for a gear wheel-shaft direct frictional joint. The small difference between the operating pitch diameter of the gear and the mounting diameter of the frictional joint is the key feature of the connection. The contact surface of the frictional joint must be placed outside the bottom land of the gear, and the geometry of the joint is limited to the specific type of solutions.The strength analysis is based on the relation between the torque and statistical load intensity of the gear transmission. Several dimensionless parameters are introduced to simplify the calculations. Stress-strain verifying analysis with respect to combined loading, the condition of appropriate load-carrying capacity of the frictional joint and the fatigue strength of the shaft are applied to obtain the relations between the dimensions of the joint and other parameters. The final engineering solution may then be suggested. The approach is illustrated by a numerical example.The proposed procedure can be useful in design projects for small, high-powered modern reducers and new-generation geared motors, in particular when manufactured in various series of types

Irradiation-assisted stress corrosion cracking of austenitic stainless steels: Recent progress and new approaches

Irradiation-assisted stress corrosion cracking (IASCC) of several types of BWR field components fabricated from solution-annealed austenitic stainless steels (SSs), including a core internal weld, were investigated by means of slow-strain-rate test (SSRT), scanning electron microscopy (SEM), Auger electron spectroscopy (AES), and field-emission-gun advanced analytical electron microscopy (FEG-AAEM). Based on the results of the tests and analyses, separate effects of neutron fluence, tensile properties, alloying elements and major impurities identified in the American Society for Testing and Materials (ASTM) specifications, minor impurities, water chemistry, and fabrication-related variables were determined. The results indicate strongly that minor impurities not specified by the ASTM-specifications play important roles, probably through a complex synergism with grain-boundary Cr depletion. These impurities, typically associated with steelmaking and component fabrication processes, are very low or negligible in solubility in steels and are the same impurities that have been known to promote intergranular SCC significantly when they are present in water as ions or soluble compounds. It seems obvious that IASCC is a complex integral problem which involves many variables that are influenced strongly by not only irradiation conditions, water chemistry, and stress but also iron and steelmaking processes, fabrication of the component, and joining and welding. Therefore, for high-stress components in particular, it would be difficult to mitigate IASCC problems at high fluence based on the consideration of water chemistry alone, and other considerations based on material composition and fabrication procedure would be necessary as well

Environmentally assisted cracking in light water reactors. Semiannual report, October 1993--March 1994. Volume 18

This report summarizes work performed by Argonne National Laboratory (ANL) on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) during the six months from October 1993 to March 1994. EAC and fatigue of piping, pressure vessels, and core components in LWRs are important concerns in operating plants and as extended reactor lifetimes are envisaged. Topics that have been investigated include (a) fatigue of low-alloy steel used in piping, steam generators, and reactor pressure vessels, (b) EAC of wrought and cast austenitic stainless steels (SSs), and (c) radiation-induced segregation and irradiation-assisted stress corrosion cracking (IASCC) of Type 304 SS after accumulation of relatively high fluence. Fatigue tests have been conducted on A302-Gr B low-alloy steel to verify whether the current predictions of modest decreases of fatigue life in simulated pressurized water reactor water are valid for high-sulfur heats that show environmentally enhanced fatigue crack growth rates. Additional crack growth data were obtained on fracture-mechanics specimens of austenitic SSs to investigate threshold stress intensity factors for EAC in high-purity oxygenated water at 289{degrees}C. The data were compared with predictions based on crack growth correlations for wrought austenitic SS in oxygenated water developed at ANL and rates in air from Section XI of the ASME Code. Microchemical and microstructural changes in high- and commercial-purity Type 304 SS specimens from control-blade absorber tubes and a control-blade sheath from operating boiling water reactors were studied by Auger electron spectroscopy and scanning electron microscopy to determine whether trace impurity elements, which are not specified in the ASTM specifications, may contribute to IASCC of solution-annealed materials

Dynamic analysis of selected components attached to bodies of rail vehicles

Praca prezentuje metodykę badań symulacyjnych dotyczących zamocowań wybranych podzespołów przyłączonych do elementów nośnych pojazdów szynowych. Opisano metodykę obliczeń dotyczących mocowań, która może być przydatna między innymi do takich podzespołów jak zbiorniki, elementy wyposażenia zwiększającego komfort podróżowania, układy hamulcowe, a także urządzenia elektryczne. Duża liczba podłączonych urządzeń o trudnej do zamodelowania strukturze wewnętrznej może być łatwo zaimplementowana do ogólnego modelu jako układ z wieloma masami skupionymi.The paper presents a methodology of simulation studies concerning the fastening of components connected to the load-bearing elements of rail vehicles. This methodology of calculations may be useful to strength verifications of fixing of components such as tanks, travel enhancements, braking systems, and electrical equipment. A large number of atached devices, mostly with a difficult to model internal structure, can easily be implemented in the general model as a system with multiple masses

Effect of interference fit between wheel hub and axle seat of a rail vehicle on stresses in a transition zone

Przedmiotem pracy jest analiza wpływu wcisku pomiędzy kołem a czopem osi pojazdu szynowego, a także wybranych wymiarów osi na stan naprężeń w strefie przejściowej w sąsiedztwie połączenia: piasta koła - czop osi. Istotną rolę w działaniu występującego tam karbu zmęczeniowego odgrywa połączenie wciskowe i należy zbadać jego ilościowe oddziaływanie na efekty naprężeniowo-odkształceniowe. Do zbadania zjawiska zastosowano metodę elementów skończonych z elementami trójwymiarowymi oraz z kontaktem. Zagadnienie jest ważne ze względu na coraz większą prędkość jazdy współczesnych pojazdów pasażerskich oraz na zagrożenie nie tylko z powodu utraty nośności osi, ale także ze względu na możliwość występowania poślizgu pomiędzy kołem a osią.The main goal of the study is investigation of the effect of an interference fit between the wheel hub and the axle of a rail vehicle as well as some axle dimensions on the state of stress in the transition zone in vicinity of the connection: hub wheel - axle journal. An important role in behaviour of the fatigue notch occurring there plays the interference fit. The influence on the quantitative effects of the stress-strain state is to be considered. In order to investigate this phenomenon the finite element method with use of the three-dimensional elements and the contact was applied. The problem is important because of the increasing speed of modern passenger vehicles. Additionally, a threat occurs not only because of the loss of capacity of the axle, but also because of the possibility of slip between the wheel and the axle journal

Optymalizacja prototypu żurawia hydraulicznego

The paper presents an application of research methodology leading to structural optimization of a crane model containing hydraulic cylinders. CAD and CAE systems were used to obtain a three-dimensional model of the crane and state of stresses and displacements, as well as to carry out appropriate optimization procedures. This issue is important from the point of view of full strength verification of modern transport equipment, particularly at the design stage, while detailed experimental research is not yet conducted.Praca prezentuje metodykę badań prowadzącą do optymalizacji strukturalnej żurawia zawierającego siłowniki hydrauliczne. Zastosowano systemy CAD i CAE do uzyskania trójwymiarowego modelu żurawia oraz stanu naprężeń i przemieszczeń, a także do przeprowadzenia odpowiednich operacji optymalizacyjnych. Zagadnienie jest istotne z punktu widzenia pełnej weryfikacji wytrzymałościowej nowoczesnych urządzeń transportu bliskiego zwłaszcza na etapie projektowania, gdy jeszcze nie prowadzi się szczegółowych badań doświadczalnych

Radiation-induced instability of MnS precipitates and its possible consequences on irradiation-induced stress corrosion cracking of austenitic stainless steels

Irradiation-assisted stress corrosion cracking (IASCC) is a significant materials issue for the light water reactor (LWR) industry and may also pose a problem for fusion power reactors that will use water as coolant. A new metallurgical process is proposed that involves the radiation-induced release into solution of minor impurity elements not usually thought to participate in IASCC. MnS-type precipitates, which contain most of the sulfur in stainless steels, are thought to be unstable under irradiation. First, Mn transmutes strongly to Fe in thermalized neutron spectra. Second, cascade-induced disordering and the inverse Kirkendall effect operating at the incoherent interfaces of MnS precipitates are thought to act as a pump to export Mn from the precipitate into the alloy matrix. Both of these processes will most likely allow sulfur, which is known to exert a deleterious influence on intergranular cracking, to re-enter the matrix. To test this hypothesis, compositions of MnS-type precipitates contained in several unirradiated and irradiated heats of Type 304, 316, and 348 stainless steels (SSs) were analyzed by Auger electron spectroscopy. Evidence is presented that shows a progressive compositional modification of MnS precipitates as exposure to neutrons increases in boiling water reactors. As the fluence increases, the Mn level in MnS decreases, whereas the Fe level increases. The S level also decreases relative to the combined level of Mn and Fe. MnS precipitates were also found to be a reservoir of other deleterious impurities such as F and O which could be also released due to radiation-induced instability of the precipitates

Development of the Methods for Testing Mechanical Properties of the Rolling Stock During the 60 Years of History of the Railway Institute

W artykule przedstawiono rozwój techniki kolejowej, a w następstwie rozwój możliwości badawczych Laboratorium Badań Taboru Instytutu Kolejnictwa w zakresie własności mechanicznych pojazdów szynowych. Omówiono badania własności wytrzymałościowych gwarantujących bezpieczeństwo bierne obsługi i pasażerów, techniki hamulcowej i dynamicznego oddziaływania pojazdów z torem kolejowym. Zaprezentowano rys historyczny prowadzenia badań oraz stan aktualny. Opisano bazę stanowiskowo-pomiarową wykorzystywaną w czasie badań oraz ich potencjalny zakres.The paper presents the development of railway engineering followed by the development of research capabilities of the Railway Institute's Rolling Stock Testing Laboratory in the field of testing mechanical properties of rail vehicles. Tests of mechanical properties necessary to guarantee passive safety of the staff and the passengers, brake technology and dynamic interaction between vehicle and track are discussed. Historical outline of test procedures as well as current situation are presented. Testing and measuring equipment used for the testing, together with their potential range, are described

Irradiation-induced sensitization of austenitic stainless steel in-core components

High- and commercial-purity specimens of Type 304 SS from BWR absorber rod tubes, irradiated during service to fluence levels of 6 {times} 10{sup 20} to 2 {times} 10{sup 21} n{center dot}cm{sup {minus}2} (E > 1 MeV) in two reactors, were examined by Auger electron spectroscopy to characterize irradiation-induced grain boundary segregation and depletion of alloying and impurity elements, which have been associated with irradiation-assisted stress corrosion cracking (IASCC) of the steel. Ductile and intergranular fracture surfaces were produced by bending of hydrogen-charged specimens in the ultra-high vacuum of Auger microscope. The intergranular fracture surfaces in high-fluence commercial-purity material were characterized by relatively high levels of Si, P, and In segregation. An Auger energy peak at 59 eV indicated either segregation of an unidentified element or formation of an unidentified compound on the grain boundary. In contrast to the commercial-purity material, segregation of the impurity elements and intergranular failure in the high-purity material were negligible for a similar fluence level. However, grain boundary depletion of Cr was more significant in high-purity material than in commercial-purity material, which indicates that irradiation-induced segregation of impurity elements and depletion of alloying elements are interdependent. 7 refs., 10 figs., 2 tabs