On October 18, 2018 USEA "Lyuben Karavelov" is celebrating 80 years since its establishment.
Faculty: Mechanics and Mathematics
Contact hours: 15h, 15h lectures, 0h seminars
Self-study hours: 30h, 15h tutoring,, 15h practical training
Year, semester, weekly workload: Year 2, semester 3, lectures 1.0h,
ECTS - 1
Main topics: The academic subject „Strength of Materials“ comprises:
Subject matter , aims and objectives of the discipline. Theoretical model of a deformable rigid body. Hands-on hypotheses. Definition of cross section forces. Method of the intersection for determining cross section forces and drawing of their diagrams. A case-study of a plane. Differential relations of Jurawski. Checking on diagrams of cross section forces, double-checking of the same for the spatial task. Moments of inertia - definitions. Moments of inertia in translation of the coordinate system. Steiner's theorem. Major central inertia axes and moments. Moments of inertia of some simple geometric shapes.
Strain state – definitions and sign convention.Three-dimensional stress state. Basic theorems. Main normal stresses and directions. Ellipsoid of Lame. Two-dimensional stress state - analytical and graphical representation (Mohr's circle). Deformed state. Definitions and sign convention. Differential equations of Cauchy. Generalized and simple Hooke's law. Poisson's ratio. General plan for solving the task of resistance of materials. Pure strength (pressure). Definitions. Stress and strain state. Experimental study. Acceptable tensile strengths. Statically indeterminate tasks in pure tension (compression). Pure twisting of cylindrical beams with circular and annular cross-section. Statically determinate and indeterminate tasks. Pure twisting of beams of non-circular cross-section. Bending; classification - types of bending. Pure specific bending - normal stresses. Navier formula Special bending combined with shear stress. Zhuravski Formula. Application of the Navier and Zhuravski formulas for different sections - composed and rolled. Major normal strains of special bending combined with shear stress. Complete dimensioning. Overall bending. Stress state. Dimensioning. Bending deformation. Method of integrating the differential equation of the elastic line. Definitions. Deformation work and potential energy of deformation. Theorem of Clapeyron. Integrals of Maxwell - Mohr. Kastilyano theorem. Rule of Vereshchagin. Classic and contemporary theories of strength. Dimensioning in bending combined with tensile strength (compression). Determining of the nucleus of different cross-sections. Determining acceptable force. Determining of the nucleus of different cross-sections. Determining acceptable force. Buckling - definitions. Euler's formula for critical force, major cases, limit of applicability. Buckling above the limit of proportionality. Dimensioning - the classic method, j - method.
Course assignments cover all units, whereupon it is required from each student to prepare an individual assignment as they shall develop an independent study on stress and strain states of a structure or a part of it under the influence of an external load.
For the extracurricular sessions, of 90 hours, some other course tasks are assigned.