Report of the Automobile Research Committee on Contraction of Aluminium Alloy Bearings

1945 ◽  
Vol 40 (2) ◽  
pp. 205-228
Author(s):  
L. Farkas ◽  
H. Ludicke
Keyword(s):  
Aluminium Alloy ◽  
Wall Thickness ◽  
Effect Of Temperature ◽  
Connecting Rod ◽  
Research Committee ◽  
Bearing Material ◽  
Interference Fit ◽  
Set Up ◽  
Bearing Alloy ◽  
And Control

The nature and the causes of contraction of aluminium alloy bearings have been investigated. Previous test results indicated that contraction is due to plastic straining of the bearing material. This is confirmed by calculation of the stresses set up in the bearing alloy, which are caused by the interference fit between bearing and housing and the differential thermal expansion of aluminium alloy and steel. The variables affecting bearing contraction are then considered under the headings:—( a) Strength of material; ( b) interference fit; ( c) bearing wall thickness; ( d) bearing size; ( e) connecting-rod wall thickness. Finally, the effect of temperature upon bearing clearance is considered. The results show that contraction can be prevented by a suitable choice of the bearing material and control of the dimensions. In particular, the interference fit should be kept low, and an alloy should be used which has a relatively high elastic limit in compression. The application of the results may be extended to light alloy bearings in general and for both bush type and split bearings fitted in steel housings.

Calculation and study of the failure of the connecting-rod small end based on thermoelastic plasticity

2016 ◽  
Vol 231 (11) ◽  
pp. 1489-1499
Author(s):  
Guohua Chen ◽  
Ridong Liao ◽  
Xue Jiang
Keyword(s):  
Contact Force ◽  
Wall Thickness ◽  
Loading Condition ◽  
Thermal Loading ◽  
Operating Temperature ◽  
Thermomechanical Coupling ◽  
Plasticity Model ◽  
High Power Density ◽  
Connecting Rod ◽  
Interference Fit

In this study, the mechanisms that cause bush loosening and rotation failure were studied on the connecting-rod small end of a high-power-density engine. Using the thermoelastic plasticity model and the thermomechanical coupling method, the stress field and the assembly contact force of the connecting-rod small end were predicted by considering four different loading conditions: first, the initial loading condition; second, the thermal loading condition; third, the mechanical loading condition; fourth, the unloading condition. This process showed the effects of the initial interference fit, the operating temperature and the wall thickness of the bush on the assembly contact force. It was found that, first, a large interference leads to a small assembly contact force after unloading, second, a higher operating temperature significantly reduces the assembly contact force and, third, the wall thickness of the bush has little influence on the assembly contact force. In conclusion, a high operating temperature is the main cause of bush loosening and rotation. This conclusion was validated by the experimental results. On the basis of this study, it is suggested that the operating temperature is limited in order to maintain the reliability of the connecting-rod small end.

The Optimization of Small End Bushings of Connecting-Rod in Heavy-Load Diesel Engines

2014 ◽  
Vol 556-562 ◽  
pp. 1215-1219
Author(s):  
Song Yin ◽  
Wen Jie Qin
Keyword(s):  
Element Model ◽  
Radial Deformation ◽  
Connecting Rod ◽  
Heavy Load ◽  
Interference Fit ◽  
Safety Coefficient ◽  
Pareto Optimal Set ◽  
Approximate Mathematical Model ◽  
Set Up ◽  
Optimal Set

The mechanical fit between the connecting rod's small end and the bush is a typical interference fit. In this paper, an elastic-plastic finite element model of the assembly of the connecting rod and the bush is built based on ABAQUS simulation platform and simulation experiments are carried out by adopting the method of design of experiments. The magnitude of interference and the thickness of the bush are set as the test factors and the maximum radial deformation of the connecting rod’s small end hole, the radial contact pressure between the connecting rod and the bush, the plastic deformation of the bush and the fatigue strength safety coefficient of the connecting rod small end are set as the response variables. Based on the response surface equations, the multi-objective optimal approximate mathematical model is set up and the Pareto optimal set are gained and discussed.

Based on the Nonlinear Dynamic Analysis of Linkage Vibration and Prevention

2014 ◽  
Vol 971-973 ◽  
pp. 410-413
Author(s):  
Wen Juan Zhao
Keyword(s):  
Control Strategy ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Preventive Measures ◽  
Mechanical Vibration ◽  
Nonlinear Dynamic Analysis ◽  
Connecting Rod ◽  
Nonlinear Dynamic Model ◽  
Set Up ◽  
And Control

connecting rod mechanism under the condition of high speed operation, organization, the elastic dynamic response of not only make the institutions of trajectory deviation, also can cause fatigue failure, this paper set up an accurate view of the nonlinear dynamic model of analysis of linkage performance and characteristics of mechanical vibration, look for the causes of various vibration, and puts forward corresponding preventive measures and control strategy.

scholarly journals Effect of Temperature and Micro structural Evolution of Magnesium and Aluminium Alloy using Vacuum Diffusion Bonding

2019 ◽  
Vol 8 (6S2) ◽  
pp. 603-605
Keyword(s):  
Surface Treatment ◽  
Aluminium Alloy ◽  
Diffusion Bonding ◽  
Structural Evolution ◽  
Effect Of Temperature ◽  
Shear Tests ◽  
Aluminum Composite ◽  
Basic Strategy ◽  
Magnesium Compound ◽  
Set Up

This work is directed to acquire better understanding and portrayal of the dissemination holding of comparable and disparate metals. It additionally meant to get ideal parameters for dispersion holding of aluminum covering over magnesium compound with Aluminum composite. This work targets building up a basic strategy to get dispersion holding joints at moderately not ease. On one hand, the exploration is expected to set up a strategy. This technique is concocted to contemplate the physical wonders that have huge effect on dissemination holding, for example, time, temperature, weight on joints and metallurgical qualities. Elastic and shear tests are to be directed. This work is directed to acquire better understanding and portrayal of the dispersion holding of comparable and unique metals. It likewise intended to ge t ideal parameters for dissemination holding of aluminum covering over magnesium combination with aluminum composite. These two metals are jointed inside the kick the bucket in the wake of completing surface treatment. At that point the bite the dust is kept inside the dispersion holding machine by shifting the time, temperature, weight by methods for burden.

Pittenweem Priory and the conventuality question

2017 ◽  
Vol 68 (1) ◽  
pp. 19-37 ◽  
Author(s):  
Anthony Lodge
Keyword(s):  
Fifteenth Century ◽  
Traditional View ◽  
Archaeological Evidence ◽  
Significant Development ◽  
New Mother ◽  
Set Up ◽  
And Control

Pittenweem Priory began life as the caput manor of a daughter-house established on May Island by Cluniac monks from Reading (c. 1140). After its sale to St Andrews (c. 1280), the priory transferred ashore. While retaining its traditional name, the ‘Priory of May (alias Pittenweem)’ was subsumed within the Augustinian priory of St Andrews. Its prior was elected from among the canons of the new mother house, but it was many decades before a resident community of canons was set up in Pittenweem. The traditional view, based principally on the ‘non-conventual’ status of the priory reiterated in fifteenth-century documents, is that there was ‘no resident community’ before the priorship of Andrew Forman (1495–1515). Archaeological evidence in Pittenweem, however, indicates that James Kennedy had embarked on significant development of the priory fifty years earlier. This suggests that, when the term ‘non-conventual’ is used in documents emanating from Kennedy's successors (Graham and Scheves), we should interpret it more as an assertion of superiority and control than as a description of realities in the priory.

scholarly journals Infection Prevention Considerations for a Multi-Mission Convention Center Field Hospital in Baltimore, Maryland during the COVID-19 Pandemic

2021 ◽  
pp. 1-21
Author(s):  
Jennifer A. Jones ◽  
Zishan K. Siddiqui ◽  
Charles Callahan ◽  
Surbhi Leekha ◽  
Sharon Smyth ◽  
...  
Keyword(s):  
Best Practices ◽  
Infection Prevention ◽  
Diagnostic Testing ◽  
The United States ◽  
Infection Prevention And Control ◽  
Field Hospital ◽  
First Case ◽  
Convention Center ◽  
Set Up ◽  
And Control

Abstract The state of Maryland identified its first case of COVID-19 on March 5, 2020. The Baltimore Convention Center (BCCFH) quickly became a selected location to set up a 250-bed inpatient Field Hospital and Alternate Care Site. In contrast to other field hospitals throughout the United States, the BCCFH remained open throughout the pandemic and took on additional COVID-19 missions, including community SARS-CoV-2 diagnostic testing, monoclonal antibody infusions for COVID-19 outpatients, and community COVID-19 vaccinations. At the time of publication, the BCCFH had cared for 1,478 COVID-19 inpatients, performed 108,155 COVID-19 tests, infused 2,166 COVID-19 patients, and administered 115,169 doses of COVID-19 vaccine. To prevent the spread of pathogens during operations, infection prevention and control guidelines were essential to ensure the safety of staff and patients. Through multi-agency collaboration, utilization of infection prevention best practices, and answering what we describe as “PPE-ESP”, an operational framework was established to reduce infection risks for those providing or receiving care at the BCCFH during the COVID-19 pandemic.

scholarly journals Real time surveillance of COVID-19 space and time clusters during the summer 2020 in Spain

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nicolás Rosillo ◽  
Javier Del-Águila-Mejía ◽  
Ayelén Rojas-Benedicto ◽  
María Guerrero-Vadillo ◽  
Marina Peñuelas ◽  
...  
Keyword(s):  
Real Time ◽  
Scan Statistic ◽  
Cluster Aggregation ◽  
Space And Time ◽  
Spatial Trends ◽  
Community Transmission ◽  
Low Incidence ◽  
Set Up ◽  
And Control ◽  
Time Scan

Abstract Background On June 21st de-escalation measures and state-of-alarm ended in Spain after the COVID-19 first wave. New surveillance and control strategy was set up to detect emerging outbreaks. Aim To detect and describe the evolution of COVID-19 clusters and cases during the 2020 summer in Spain. Methods A near-real time surveillance system to detect active clusters of COVID-19 was developed based on Kulldorf’s prospective space-time scan statistic (STSS) to detect daily emerging active clusters. Results Analyses were performed daily during the summer 2020 (June 21st – August 31st) in Spain, showing an increase of active clusters and municipalities affected. Spread happened in the study period from a few, low-cases, regional-located clusters in June to a nationwide distribution of bigger clusters encompassing a higher average number of municipalities and total cases by end-August. Conclusion STSS-based surveillance of COVID-19 can be of utility in a low-incidence scenario to help tackle emerging outbreaks that could potentially drive a widespread transmission. If that happens, spatial trends and disease distribution can be followed with this method. Finally, cluster aggregation in space and time, as observed in our results, could suggest the occurrence of community transmission.

scholarly journals Development of an Exercise Training Protocol to Investigate Arteriogenesis in a Murine Model of Peripheral Artery Disease

2019 ◽  
Vol 20 (16) ◽  
pp. 3956 ◽  
Author(s):  
Ayko Bresler ◽  
Johanna Vogel ◽  
Daniel Niederer ◽  
Daphne Gray ◽  
Thomas Schmitz-Rixen ◽  
...  
Keyword(s):  
Peripheral Artery Disease ◽  
Suitable Model ◽  
Peripheral Artery ◽  
Running Wheel ◽  
Limb Perfusion ◽  
Collateral Growth ◽  
Artery Disease ◽  
Set Up ◽  
Exercise Induced ◽  
And Control

Exercise is a treatment option in peripheral artery disease (PAD) patients to improve their clinical trajectory, at least in part induced by collateral growth. The ligation of the femoral artery (FAL) in mice is an established model to induce arteriogenesis. We intended to develop an animal model to stimulate collateral growth in mice through exercise. The training intensity assessment consisted of comparing two different training regimens in C57BL/6 mice, a treadmill implementing forced exercise and a free-to-access voluntary running wheel. The mice in the latter group covered a much greater distance than the former pre- and postoperatively. C57BL/6 mice and hypercholesterolemic ApoE-deficient (ApoE−/−) mice were subjected to FAL and had either access to a running wheel or were kept in motion-restricting cages (control) and hind limb perfusion was measured pre- and postoperatively at various times. Perfusion recovery in C57BL/6 mice was similar between the groups. In contrast, ApoE−/− mice showed significant differences between training and control 7 d postoperatively with a significant increase in pericollateral macrophages while the collateral diameter did not differ between training and control groups 21 d after surgery. ApoE−/− mice with running wheel training is a suitable model to simulate exercise induced collateral growth in PAD. This experimental set-up may provide a model for investigating molecular training effects.

Optimization of the Wrist Pin End of an Automobile Engine Connecting Rod With an Interference Fit

1990 ◽  
Vol 112 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Vijay Sarihan ◽  
Ji Oh Song
Keyword(s):  
Finite Element ◽  
Optimum Design ◽  
Three Dimensional ◽  
Stress Singularity ◽  
Design Strategy ◽  
Structural Components ◽  
Connecting Rod ◽  
Fem Model ◽  
Automobile Engine ◽  
Interference Fit

Current design procedures for complicated three-dimensional structural components with component interactions may not necessarily result in optimum designs. The wrist pin end design of the connecting rod with an interference fit is governed by the stress singularity in the region where the wrist pin breaks contact with the connecting rod. Similar problems occur in a wide variety of structural components which involve interference fits. For a better understanding of the problems associated with obtaining optimum designs for this important class of structural interaction only the design problems associated with the wrist pin end of the rod are addressed in this study. This paper demonstrates a procedure for designing a functional and minimum weight wrist pin end of an automobile engine connecting rod with an interference fit wrist pin. Current procedures for Finite Element Method (FEM) model generation in complicated three-dimensional components are very time consuming especially in the presence of stress singularities. Furthermore the iterative nature of the design process makes the process of developing an optimum design very expensive. This design procedure uses a generic modeler to generate the FEM model based on the values of the design variables. It uses the NASTRAN finite element program for structural analysis. A stress concentration factor approach is used to obtain realistic stresses in the region of the stress singularity. For optimization, the approximate optimization strategy in the COPES/CONMIN program is used to generate an approximate design surface, determine the design sensitivities for constrained function minimization and obtain the optimum design. This proposed design strategy is fully automated and requires only an initial design to generate the optimum design. It does not require analysis code modifications to compute the design sensitivities and requires very few costly NASTRAN analyses. The connecting rod design problem was solved as an eight design variable problem with five constraints. A weight reduction of nearly 27 percent was achieved over an existing design and required only thirteen NASTRAN analyses. It is felt that this design strategy can be effectively used in an engineering environment to generate optimum designs of complicated three-dimensional components.

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