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Research Interests:
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Research Interests:
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Research Interests: Business and Agriculture
Fretting as a damaging way of the surface in contact is known for over 80 years. In the last 20 years there have been important achievements in the experimental research, understanding and description of the mechanisms that lead to this... more
Fretting as a damaging way of the surface in contact is known for over 80 years. In the last 20 years there have been important achievements in the experimental research, understanding and description of the mechanisms that lead to this phenomenon. From the definition of the phenomenon of fretting and the study of the influence of various factors on fretting it was concluded that the main factor in the occurrence of fretting is the existence of the relative oscillating movement of small and very small amplitude between the contact surfaces under the action of a normal tasks.
Research Interests: Fretting and Phenomenon
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, fretting-fatigue and fretting... more
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, fretting-fatigue and fretting corrosion. Three fretting regimes will be considered: stick regime, slip regime and mixed regime. Obviously the partial slip transition develops the highest stress levels which can induce fatigue crack nucleation depending on the fatigue properties of the two contacting first bodies. Therefore prediction of the frontier between partial slip and gross slip is required.
Research Interests:
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. The present paper argues that adhesion forces and elastic deformation in the contact zone... more
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. The present paper argues that adhesion forces and elastic deformation in the contact zone may contribute significantly to the relative displacement during fretting of metals A tangential force whose magnitude is less equal on greater than the force of limiting friction will not give rise to a sliding motion. It is determined the energy loss dissipated per fretting cycle
Fretting regimes were first mapped by Vingsbo. In a similar way, three fretting regimes will be considered: stick regime, slip regime and mixed regime. The mixed regime was made up of initial gross slip followed by partial slip condition... more
Fretting regimes were first mapped by Vingsbo. In a similar way, three fretting regimes will be considered: stick regime, slip regime and mixed regime. The mixed regime was made up of initial gross slip followed by partial slip condition after a few hundred cycles. For the study of the fretting phenomenon in case of elastics assemblages spring slides with multiple sheets, I used the experimental stall. On the rigid support the elastic lamella is assembling through the agency of the superior plate and of the screws. The elastic lamella oscillates because of the rod crank mechanism with eccentric. This mechanism is auctioned with the electrical engine assuring the necessary conditions for producing the fretting phenomenon
There are two factors that reduce the opportunity for certification process as capable. The first factor is the volume of production and the second factor is related to the level of precision required by the client runtime, ie the size... more
There are two factors that reduce the opportunity for certification process as capable. The first factor is the volume of production and the second factor is related to the level of precision required by the client runtime, ie the size tolerances. The tolerance is low, the capability value decreases and the process must be improved to meet the minimum capability values. Both aspects of production volumes and related capabilities accuracy (precision and accuracy of the estimate process capability) are combined in a calculation of economic efficiency, it finally generates design quality system.
Fretting phenomenon is a complex deterioration phenomenon that can be found in most technicalapplications which require the existence of contacts undergoing a small amplitude oscillatory motion. Frettinghas two sides, one given by... more
Fretting phenomenon is a complex deterioration phenomenon that can be found in most technicalapplications which require the existence of contacts undergoing a small amplitude oscillatory motion. Frettinghas two sides, one given by fretting-wear and another one given by fretting-fatigue, both leading to specificdeteriorations.
Fretting damage is often the origin catastrophic failures or loss of functionality in many industrial applications. Considered as a plague for modern industry, fretting is encountered in all quasi-static loadings submitted to vibration... more
Fretting damage is often the origin catastrophic failures or loss of functionality in many industrial applications. Considered as a plague for modern industry, fretting is encountered in all quasi-static loadings submitted to vibration and thus concerns many industrial branches. The main parameters were reported to be amplitude displacement, normal load, frequency, surface roughness and morphology, and residual stresses. The present paper argues that adhesion forces and elastic deformation in the contact zone may contribute significantly to the relative displacement during fretting of metals.
Fretting as a damaging way of the surface in contact is known for over 80 years. In the last 20 years there have been important achievements in the experimental research, understanding and description of the mechanisms that lead to this... more
Fretting as a damaging way of the surface in contact is known for over 80 years. In the last 20 years there have been important achievements in the experimental research, understanding and description of the mechanisms that lead to this phenomenon. As fretting mechanisms can be discussed in close relation with many other aspects (egmovement, materials, contact, geometry, load, test device dynamics etc), and general presentation will be followed .
A communities of practice is a group of people who share a concern, a set of problems or a passion about a common topic, a passion for a professional or personal activity. Universities may be regarded as professional communities in which... more
A communities of practice is a group of people who share a concern, a set of problems or a passion about a common topic, a passion for a professional or personal activity. Universities may be regarded as professional communities in which joint activities are carried out, with well-defined structures. Using networks at university level increases joint assembly of ideas held by each individual, while the exchange of ideas and practices inevitably may lead to the system enrichment, producing effectively loops of innovation and development.
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, frettingfatigue and fretting... more
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, frettingfatigue and fretting corrosion. Fretting regimes were first mapped by Vingsbo. In a similar way, three fretting regimes will be considered: stick regime, slip regime and mixed regime. The mixed regime was made up of initial gross slip followed by partial slip condition after a few hundred cycles. Obviously the partial slip transition develops the highest stress levels which can induce fatigue crack nucleation depending on the fatigue properties of the two contacting first bodies. Therefore prediction of the frontier between partial slip and gross slip is required.
For "non-conforming" contact where deformations are small enough compared to body dimensions, the theoretical elasticity will apply to the closed contact defined by the contact area.The tension can be calculated by considering... more
For "non-conforming" contact where deformations are small enough compared to body dimensions, the theoretical elasticity will apply to the closed contact defined by the contact area.The tension can be calculated by considering each body as a solid semiinfinite, limited by a flat surface, that is to say a semisphere of elasticity. This idealization, where the bodies have the surface of the arbitrary profile and seen as a semifinished extension is almost universal for the elastic contacts.Tensions and displacements in the elastic semisphere can determine surface tractions being deduced for the first time by Boussinesq (1885) and Cerruti (1882) who have made the theory of potential, and this approach is presented by Love as well (1957)
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Correct analysis of a malfunction is a very important step in the remediation process of a product. It is necessary to have a clear vision, especially to determine the cause of the malfunction, although sometimes it can be masked by other... more
Correct analysis of a malfunction is a very important step in the remediation process of a product. It is necessary to have a clear vision, especially to determine the cause of the malfunction, although sometimes it can be masked by other defects. Quality Management offers many classic and modern tools to help find solutions that ensure quality improvement. This paper presents a modern method of quality management, called the tree diagram, applied to the issue of increasing the reliability of the chain transmissions. The advantage of using this chart is that it offers the possibility of logically and chronologically examining the objectives and actions that solve a quality or non-quality problem. In the proposed case study, the overall objective is to increase the reliability of the chain transmissions. Specific objectives are set and for each specific objective, we identify potential solutions that can be adopted. For the proposed general objective, the following three specific obj...
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In this work the authors present the result of the theoretical researches and experiences concerning the identification and elimination of the tight places in the automatic montage of the electric ignition devices used in the pyrotechnic... more
In this work the authors present the result of the theoretical researches and experiences concerning the identification and elimination of the tight places in the automatic montage of the electric ignition devices used in the pyrotechnic industry for improving the labour productivity. Taking into account the fact the above production system is an expectation system depending on a theoretical study followed by computer simulation with the data processing product WINQSB, Queing System Simulation module, we identified the tight places that generate expectation queues when remaking, verifying and assembling the electric ignition devices of the indigenous electric detonators. In this way, using the WINQSB simulation, we offered solutions for 3 analysis types: the ensemble and marks analysis which entered the system, the analysis of the working machines using and the analysis of the queues.
Research Interests:
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, fretting-fatigue and fretting... more
Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, fretting-fatigue and fretting corrosion. Fretting regimes were first mapped by Vingsbo. In a similar way, three fretting regimes will be considered: stick regime, slip regime and mixed regime. The mixed regime was made up of initial gross slip followed by partial slip condition after a few hundred cycles. Obviously the partial slip transition develops the highest stress levels which can induce fatigue crack nucleation depending on the fatigue properties of the two contacting first bodies. Therefore prediction of the frontier between partial slip and gross slip is required.
Research Interests:
It presents the mechanisms of the bird’s legs, by exemplifying with the parrot. It gives structural data and they are written mathematical relationships which are necessary to write the calculations of these mechanisms. It shows how these... more
It presents the mechanisms of the bird’s legs, by exemplifying with the parrot. It gives structural data and they are written mathematical relationships which are necessary to write the calculations of these mechanisms. It shows how these mechanisms can be used as prehensile mechanisms, but also as stepping mechanisms. Such mechanisms can be used, for example, for the robots that are displaced on narrow bars.
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Fretting damage is often the origin catastrophic failures or loss of functionality in many industrial applications. Considered as a plague for modern industry, fretting is encountered in all quasi-static loadings submitted to vibration... more
Fretting damage is often the origin catastrophic failures or loss of functionality in many industrial applications. Considered as a plague for modern industry, fretting is encountered in all quasi-static loadings submitted to vibration and thus concerns many industrial branches. The main parameters were reported to be amplitude displacement, normal load, frequency, surface roughness and morphology, and residual stresses. The present paper argues that adhesion forces and elastic deformation in the contact zone may contribute significantly to the relative displacement during fretting of metals.
Research Interests:
There is no industrial sector in which welding is not used as a manufacturing process. Welding assembly is a highly polluting technology process, especially of the atmosphere and soil. The formation of gases in the welding process is the... more
There is no industrial sector in which welding is not used as a manufacturing process. Welding assembly is a highly polluting technology process, especially of the atmosphere and soil. The formation of gases in the welding process is the result of burning the electrodes, flows, forming the molten metal bath and making the weld seam. Welding operators are exposed to smoke and toxic gases resulting from the welding process, which may be dangerous to health. Many acute intoxications due to excessive exposure or short-term exposure to smoke and gas resulting from the welding process have been studied over time. However, in addition to general effects such as respiratory irritation, long-term effects have been directly attributed the influence of smoke and toxic gases, for example, the chronic effects due to the presence of chromium, nickel and aluminum. There are some welding sections where the level of noxes exceeds the limits allowed by the law, and in these cases it is fairly possibl...
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The occupational risk assessment of a machine building company must cover each activity and workstation, taking into account each component of the production system (work system), each workload, work equipment and the work environment.... more
The occupational risk assessment of a machine building company must cover each activity and workstation, taking into account each component of the production system (work system), each workload, work equipment and the work environment. This assessment is an extremely complicated and complex issue since the production system of such an enterprise is particularly complex and complicated. Welding assembly is a highly polluting technology process, especially of the atmosphere and soil. The formation of gases in the welding process is the result of burning of the electrodes, powders, forming the molten metal bath and making the weld seam. Welding operators are exposed to smoke and toxic gases resulting from the welding process, which can in many cases be hazardous to health. Many acute intoxications that may be caused by excessive exposure to or short exposure to smoke and gas resulting from the welding process have been studied over time. In the paper are presented the elements of risk ...
There are given details about the cochleoid geometry and there are traced, based on equations, different areas of cochleoid, based on a supporting mechanism. They are shown the laws of variation of the curvature radius and of the tracer... more
There are given details about the cochleoid geometry and there are traced, based on equations, different areas of cochleoid, based on a supporting mechanism. They are shown the laws of variation of the curvature radius and of the tracer point coordinates. It is studied the material point movement on the cochleoid and there are presented relationships and diagrams for speeds and accelerations.
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Research Interests:
The work relates to practical conceivement and achievement of mecanical and action structure of an antropomorphe industrial robot with 4 freedom degrees + gripper, conceived at “C. Brâncuşi” University – Târgu Jiu for didactical usage.... more
The work relates to practical conceivement and achievement of mecanical and action structure of an antropomorphe industrial robot with 4 freedom degrees + gripper, conceived at “C. Brâncuşi” University – Târgu Jiu for didactical usage. The work presents cinematical chain and building solutions used for mechanical structures, actionand comand systems and speed regulate system of an industrial robot.