As we accustomed the readers of PRO LIGNO Journal during the past year, we continue to present within the FRONTLINES heading the curricula subjects of the Wood Industry Faculty in Brasov. Thus, we try to meet the interest of several categories, such as employers, future candidates and foreign students, who wish to know what knowledge and which abilities are gained by the graduates of this faculty during the 4 years of study.

We continue in this edition the prezentation of the  subjects which are taught during the 2-nd year of study. Same as for the 1-st year, the curricula is common for both specializations and it mainly comprises general technical subjects (e.g. Strength of Materials, Special Mathematics, Heat Engineering, Machine Parts, Programming), but also some speciality-specific subjects (e.g. Wood Physics and Mechanics included in a previous edition, Tolerances and Dimensional Control, Wooden Structures, Wood Preservation etc.).

Subject title: STRENGTH OF MATERIALS

Semester / Year of study: semester I and II / 2nd year

Status: compulsory

Objective:

• Substantiation of basic knowledge referring to the behaviour of mechanical deformable structures made of different materials (metal, wood, composites et al.) under static and dynamic loads.
• Gaining knowledge referring to stresses and strains from metal and wooden pieces subjected to simple and complex, static and dynamic loads. Specification of the general calculus relations concerning stresses, strains and displacements, stability and cyclic loads for samples and wooden structures (bars, frames, boards, covers et al.).

Contents:
The course and seminars, as well as laboratories are divided into several chapters, as follows:

• Introduction in Strength of Materials (aim, classification of solids and forces, calculus hypothesis, definition of stresses, strains and displacements).
• Sectional stresses: axial, shearing forces, bending moments and moments of inertia. Stresses variation diagrams for straight bars, curved bars, flat and three-dimensional frames. Mobile loads, maximum moment, method of overlapping effects.
• Geometrical characteristics of flat sections: static moments, moments of inertia.
• Stresses and strains under tensile and compression loads. The typical curve of a material, the deformation energy, static undetermined systems, collapse, collapsing pressure, elastic contact. Particularisation for wooden samples.
• Shear stresses of small-sized samples. Calculus of screws, rivets and welded joints. Wood shear, calculation of wood joints.
• Stresses and strains at flat bars torsion. Torsion stresses. Static undetermined bars. Bredt's formulas. 
• Bending stresses in straight bars. Naviers formula. Jurawskis formula. Optimal sections of bent bars. Longitudinal slip. Composed beams calculation. Wood bending. Oblique bending. Bending stresses. General formula for bending stresses calculation. Bending of bars with laminated structure. Bending of equal strength bars.
• Displacements at straight bars bending (analytical method, graphic-analytical method, overlapping of the effects, two deflections equation, three deflections equation).
• Calculation hypothesis in strength of materials (Strength theories). Strength theories for wooden samples and other anisotropic materials.
• Composed stresses. Stresses type s-s, t-t, s-t. Helical springs calculation.
• Curved bars bending stresses.
• Energetic methods for calculation of the linear-elastic displacements (Clapeyron, Castigliano, Mohr-Mawell, Veresceaghin, Betti, Maxwell).
• Static undetermined bars systems (forces method, displacements method).
• Bar stability (buckling). Particularities concerning stability of wooden bars. Euler’s formula. Timosenko’s method. Boards stability. Bending and torsion stability.
• Dynamic stresses caused by forces of inertia, the behaviour under shock stresses.
• Variable stresses (fatigue of materials). Elements of a variable stresses cycle. Wohler’s curve at metals and wood. Influencing factors of the fatigue strength. Calculation of the safety coefficient at variable stresses. Lifetime of a piece.
• Calculation of thin walls vessels.
• Calculation of rotating disks.
• Calculation of thick wall vessels.
• Calculation of flat isotropic an anisotropic boards.
• Calculation above the elasticity limit.
• Numerical methods in strength of materials (FEM et al.)
• Creep and rheology elements.
• Experimental methods for the analysis of stresses and strains from solid deformable structures (electrical resistive tensiometry, Moiré fringes, photo-elasticity, the breakable laquers method et al.).

History:
            Between 1960-1965 the discipline was taught by Prof.Dr.Eng. I. DEUTSCH; between 1965-1971 by Prof.Eng. T. REDLOV and since 1972 by Prof.Dr.Eng. I. CURTU, member of the Romanian Academy of Technical Sciences.
            Several teachers sustain at present seminary hours at this discipline, such as: Lect.Dr.Eng. Camelia CERBU, Asist.Eng. Marius BABA, PhD-Student Eng. Mariana STANCIU.
            In time, the discipline carried several denominations: “Strength of materials and elasticity theory”, “Strength of isotropic and anisotropic materials” et al.

 Present Head of Discipline:
            Ioan CURTU, Professor, PhD, graduate of the Faculty of Wood Industry, class 1966.
Title of PhD Thesis: "Research concerning the stresses and strains in the structure of wood-processing machine bodies”. Thesis asserted in June 1973 at the Polytechnical Institute of Brasov.

Publications within the field of the discipline:

• “Strength of Materials”, vol. I and II, University of Brasov Publishing House, Brasov, 1977 and 1978.
• „Strength Calculus in Wood Industry”, Technique Publishing House, Bucharest, 1982.
• „Wood and Wooden Products Mechanics”, Technique Publishing House, Bucharest, 1984.
• “Strength of Materials and Elasticity Theory”,2 volumes, University of Brasov Publishing House, Brasov, 1988.
• “Applications of Forestry Mechanics”, Ceres Publishing House, Bucharest, 1982.
• “Strength of Materials”, 4 volumes, University of Brasov Publishing House, Brasov, 1996-1999.
• “Collection of Applications in Strength of Materials”, Infomarket Publishing House, Brasov, 2000-2005

Awards/Titles:

• since 1986: Head of the “Strength of Materials and Vibrations” Department, Faculty of Mechanics;
  
• since 1988: PhD supervisor in the fundamental field ENGINEERING SCIENCES, areas: STREHGTH OF MATERIALS, ELASTICITY, PLASTICITY;
• 2002-2006: Correspondent Member of Romanian Academy of Technical Sciences;
• since 2006: Full Member of Romanian Academy of Technical Sciences.

Perspectives and Opportunities:
            The future development of the discipline considers the following directions:

• Development of the Structures Calculus Laboratory with financial support from different research contracts.
• Development of the Testing Laboratory for Isotropic and Anisotropic Materials; purchasing of a computerized testing machine.

Subject title: TOLERANCES AND DIMENSIONAL CONTROL IN WOOD INDUSTRY

Semester / Year of study: semester I / 2nd year

Status: compulsory

Objectives:

• Gaining knowledge about the manufacturing accuracy of parts and products (dimensional accuracy, shape and position accuracy, geometrical state of surfaces).
• Gaining knowledge about the main notions with regards to fits and tolerances, accuracy levels and fundamental tolerances according to ISO norms for wood processing.
• Setting up and solving of dimensions chains. Construction, dimensioning and use of checking devices in wood industry.
• Study of manufacturing errors using statistical methods of analysis and control of the processing accuracy.

Contents:

The course support contains the following chapters:

• The importance of the subject. Interchangeability. Processing errors.
• Dimensional accuracy. Dimensions. Deviations. Tolerances. Fits. Fit systems.
• Methods and means of measuring dimensions. Measuring methods. Universal measuring means.
• Precision of the geometrical shape. Linearity. Profile shape. Circularity. Flatness. Surface shape. Cylindrical shape. Methods and means to determine the deviations of the geometrical shape.
• Precision of the geometrical position. Parallelism. Perpendicularity. Inclination. Coaxiality and concentricity. Radial deviation. Frontal deviation. Intersection. Nominal position. Methods and means to determine the deviations of the geometrical position.
• Geometrical state of surfaces. Waves. Roughness.
• ISO system of tolerances and fits. Tolerances system.
• ISO system of tolerances and fits. Fits system. Recommendations for applying the ISO system. Practical examples.
• Tolerances and fits systems for wooden products. Precision levels and fundamental tolerances. Fits for wooden products. Particularities of wood fits.
• Dimensions chain. Definitions, components, classification. Solving the direct problem.
• Dimensions chain. Solving the reverse problem. Functional and technological relations for solving the dimensions chain.
• Checking devices. Dimensional checking devices. Construction, dimensioning, use.
• Checking devices. Position checking devices. Construction, dimensioning, use.
• Study of processing errors using statistics.
• Laboratory sessions cover the following thematics:
• Technique of measuring the interior and exterior dimensions.
• Study and determination of the dimensional precision.
• Study and determination of the shape and position precision.
• Study and determination of the joints and wooden products fits.
• Construction and calculus of dimensional checking devices.
• Construction and calculus of position checking device.
• Evaluation.

History:

The subject was initially included in the course entitled “Furniture Manufacturing”, taught by Prof.Dr.Eng. Valentin NASTASE until 1990. Starting with 1994 the course became individual under the title “Tolerances and Fits for Wood Industry”, being taught since then by Prof.Dr.Eng. Constantin LAZARESCU.
Beginning with 2004, the course title changed into “Tolerances and Dimensional Control in Wood Industry”, as presently specified in the curricula.

Present Head of Discipline:

Prof.Dr.Eng. Constantin LAZARESCU, graduate of the Wood Industry Faculty in Brasov, class 1975.
Title of PhD Thesis: “Contribution concerning the study of wooden dowels compression in order to assure the fits in the assembling process”. Thesis defended in December 1985 at the “Transilvania” University Brasov.

Publications within the field of discipline:

• “Tolerances and Fits for Wood Industry”. LUX-LIBRIS Publishing House, Brasov, 1995.
• “Tolerances and Fits for Wood Industry. Handbook for Laboratory Classes”. Publishing House of Transilvania University of Brasov, 1996.
• “Tolerances and Dimensional Control in Wood Industry” (Romanian version). Publishing House of Transilvania University of Brasov, 2005.
• “Tolerances and Dimensional Control in Wood Industry” (English version). Publishing House of Transilvania University of Brasov, 2005.

Awards/Titles:

• 1992-2000: Vice-Dean of Wood Industry Faculty;
• since 2004: Head of the ”Machines for Wood Industry” Department.

Perspectives and Opportunities:

The future development of the discipline considers the following directions:

• Enlargement of the endowment of the Laboratory of Tolerances and Dimensional Control of the Faculty of Wood Industry by acquisition of modern measuring and control equipment.
• Complete endowment of the Laboratory for Testing and Analysis of the Manufacturing Accuracy with performant equipment for the study of the geometrical shape of surfaces of lignin-cellulose based materials.