Volume 2, No. 15 (2009)
Articles
A STUDY OF THE INTERMEDIARY OBJECTS IN DESIGN PROCESS
ANGHEL DANIEL-CONSTANTIN, BELU NADIA
This paper presents a methodology to analyze the design process, based on the study of intermediary objects. Our main objective is to understand how and why intermediary objects appear in the course of the design process. The research method used in this work relies on observation of the design process. A laboratory experiment is used for this purpose. The results could be used to make recommendations for the designers to improve the performances of the design process.
THE EFFECT OF STRESS CONCENTRATION FACTORS IN CIRCULAR PROFILE SHAFTS SUBJECTED TO TORSION
ATANASIU COSTICĂ, SOROHAN ŞTEFAN, MIRON CONSTANTIN MATEI
The paper presents the conditions that must be implemented in stress analysis using the finite element method when the stress concentration factors in bars of circular cross section, having longitudinal holes and subjected to torsion must be accurate obtained. There are presented parametrically the stress concentration factors of some particular cross sections. In order to reduce the calculation time and effort, some facilities given by the symmetry of the cross section and the symmetry/antisymmetry of the load were used. The results are presented graphically and can be used in the design process of such structures. More than that, the methodology depicted in this paper may be used as a model for the analysis of other type of cross sections, different from the ones presented here.
CONTRIBUTIONS ON THE INFLUENCE OF THE PROCESSING PARAMETERS ON THE B WIDTH OF THE WELDING SEAM TO THE OPEN JOINT OF SHEETS BY FLUXSHIELDED ARC WELDING
BANU ILARION, POPA NICOLAE, BĂJAN ADRIAN
The paper presents the influence of the processing parameters (the welding arc voltage Ua, the welding current strength Is, the rate of welding vs and the feed rate of electrode ve.) on the penetration of the welding seam hp, using the Taguchi method.
OFFERS DIAGNOSE ANALYSIS IN SMALL AND MEDIUM COMPANIES (SME)
BOIAN NICOLAE
This paper presents the determinant elements of the offers diagnose analysis, as part of the companies market diagnose. Knowing the general characteristics of the product offer as a market variable, one can find its determinant factors like product market price and its fabrication costs. There are specific elements of the small and medium companies that influence the behaviour of the determinant factors. Depending on these elements we recommend evaluation two methods that are considered to be most important to small and medium companies both detailed theoretically and methodically. Finally we present an example of offer diagnose analysis.
THEORETICAL ASPECTS ON MATHEMATICAL MODELING OF THE MAXIMUM ALLOWABLE STATIC COMPRESSION RECEIVED TO NO MECHANICAL INJURY IN APPLES
CASANDROIU TUDOR, IVANESCU DANIELA
The value and quality of fruit are reduced both through injury by crushing the pulp tissue as well as strains and deviations from the characteristic geometric shape of the fruit, due to major production of the two forms (types) of mechanical defects in apples is static compression as they are subject to packaging (containers) due to the weight of the upper ranks, during periods of storage - warehousing - transport. The static compressive forces were evaluated, producing either cruses of the tissue of the fruit, or geometric shape changing characteristic, based on the application in a first approximation of the theory of Hertz bodies with convex surfaces, with applications to apples (apple - apple, apple - rigid flat surface). On this basis has developed a methodology for determination - evaluating pack height (container) for storage - warehousing, provided that the fruit in the bottom of the pack does not suffer mechanical defects.
HYDRAULIC DEVICE USED TO REGULATE AND CONTROL THE BLANKHOLDER FORCES DURING COLD FORMING PROCESS OF METAL SHEETS
CHIRIŢĂ CONSTANTIN (*), BRABIE GHEORGHE (**), HANGANU ADRIAN(*), DUCA CORNELIU (***), CALFA DANIEL(***)
The present theme of research proposes the elaboration of a technical solution for reduction or elimination of instability phenomena effect based on the study of blank holder force variation as a function of part configuration and different efforts that stress the material in different zones of the part. The article presented structure of hydraulic research equipment used to the metal sheets deformation, constructive and functional parameters and aspects concerning the influence of blank holder force on the intensity of instability phenomena.
EXPERIMENTAL STUDIES REGARDING THE OPTIMIZATION IN THE AREA OF THE CUTTING- OUTS FOR THE EASE OF THE REINFORCED FRAME
CRISTEA ANIŞOARA-GABRIELA
The mathematical modelling for optimization is a highly iterative process that implies a series of steps regarding the identification of the parameters and variables which characterize the analysed phenomenon, the definition of the evolution sets of the indices of these elements, the specification of the definition field of the variables, the elaboration of the objective function, writing the algebraical or differential relations which link the variables and the parameters and gathering data associated to the model. The design of a resistance structure supposes, on the basis of the stresses and strains produced by the actions it is subjected to during exploitation, to select the material needed for the execution, to establish the geometric form and to dimension the structural elements on the basis of the criteria of safety and reliability in exploitation, observing at the same time the criterion of economic efficiency.
TRENDS AND CURRENT GUIDELINES ADDRESS MANAGEMENT SYSTEMS INTEGRATED "QUALITY-ENVIRONMENT-OCCUPATIONAL HEALTH AND SAFETY" IN THE PROCESS INDUSTRIES
DURBACĂ ION, DURBAC NUŢA
A management system sets the goals and objectives, outlines the strategies and tactics, and develops the plans, schedules and necessary controls to run an organization. Around the world organizations are increasingly being pressed to guarantee the quality of their products / services while maintaining and even improving environmental and occupational health and safety performance in accordance with patterns established by society and in consonance with the concept of sustainability.
DETERMINATION OF THE LONGITUDINAL ELASTICITY MODULE AND OF THE POISSON COEFFICIENT WITH THE HELP OF ULTRASOUNDS
GOANŢĂ VIOREL, MIHĂLCUŢ MIHAI
The determination of the elastic characteristics of materials is usually done on standard test-samples whose traction strength is tested on test devices from which the force signal is collected, whereas the signals related to longitudinal and transversal strain are collected from extensometer. In case one wishes to determine the elastic characteristics of the materials of some structures that operate in the exploitation field, the previously described methods cannot apply because one cannot draw test-samples from the components of the respective structures. If we consider the fact that the materials of the exploited pieces can modify their elastic characteristics in time, their in-situ determination thus becomes necessary. Such a method is described below and is based on the determination of the speed of the longitudinal and transversal ultrasound waves via the respective materials.
MEASUREMENT OF THE RESISTANCE TO FRACTURE IN PIPES USING J INTEGRAL
GOANŢĂ VIOREL, BÎTCĂ CONSTANTIN
The experimental procedure for measurement of the notch fracture toughness using a non-standard curved specimen with a notch simulating the expected scratch damage of pipelines has been developed. The notch fracture toughness J?,c in terms of the J-integral has been estimated by means of Finite Element Analysis. The proposed procedure allows avoiding calculation of the stress intensity factor for non-standard specimens to determine the notch fracture toughness J?,c. Development of the present methodology encourages replacing the conservative crack-like defects approach
MATERIALS MANAGEMENT USING DATABASES
MĂRĂSCU KLEIN VLADIMIR
Many more complex data do change significantly as new experiments are done and new materials or material systems come along constantly and so entirely new data flood the literature. Materials scientists, like chemists, physicists and engineers, need means of finding these. The material process selection problem is a multi-attribute decision-making problem. This paper describes a prototype material process selection system that integrates a formal multi-attribute decision model with a relational database. The decision model enables the representation of the designer's preferences over the decision factors. The imprecise queries better model the qualitative requirements and designer preferences that occur in preliminary design.
ORGANIZATIONAL COHERENCE EVALUATION
MĂRĂSCU KLEIN VLADIMIR, BOIAN NICOLAE
The paper presents the principal coordinates of organizational coherence as part of technical and economical diagnose, putting into evidence the general factors of influence and type of ties between the main elements involved into organization activity. Based on the Galbraigth organizational design, the paper presents a model of analysis based on the character of different forces born inside the model. For each kind of force the model evaluates the determinant factors, the sense and the intensity of influence. Using the quest method on main persons involved in organization activity (managers, employers, clients, suppliers, collaborators), we can analyze and appreciate the importance of problems that company has to take a count to develop a long time coherence structure. More, the administration is able to prevent consequences of changes into their future activity. Conclusions refer also to implication of strategic changes in coherence damaging taking into consideration the probability of these to happen.
MORE TEXTILE WASTE OR CHILDREN'S CLOTHING?
STAMATE IULIANA, ŢILICĂ DANIELA
This article deals with aspects related to the posibility of utilising the fabric ("green" cotton ) that undergoes cutting so that a high value of the index of utilisation is obtained. The waste obtained after cutting is used for manufacturing children's clothing.
CALCULATION OF CANTILEVER TRUSS BEAM DEFORMATIONS USING CONTINUUM MODELING
TODOROVIC M.(1), DEDIC M.(2)
Deformation analysis of beam-like truss structures can be significantly simplified if it is replaced by a continuum beam with bulk cross-section, so that ordinary formulas from Strength of materials can be used. An energy method is applied to calculate the equivalent bending and shearing stiffnesses for a truss cantilever beam with repeated cells loaded by a force at its free end. Different types of filling bars pattern and supports combination are analyzed. The procedure is generalized the truss simple beams, and demonstrated on examples of the end deflection and end slope calculation. Results obtained are analyzed for different ratios of number of cells and ratios of bars cross-section.