SOLID MECHANICS - 1 (S.M.1) SYLLABUS

II B.Tech. Civil - First Semester

ANU - SYLLABUS

UNIT-1

STRESS

Introduction,Method of sections; Definition of stress;Normal stresses in axially loaded bars;Shear stresses; Allowable stress and Factor of safety.

STRAIN

Normal strain; Stress- Strain relationships; Hooke's Law, Poisson's ratio;Thermal strain and deformations of axially loaded bars,statically indeterminate bars,Stress-Strain relationship for Shear.

GENERALIZED HOOKE'S LAW and PRESSURE VESSELS

Generalized Hooke's law for isotropic materials; Relationship between Modulus of elasticity and Modulus of rigidity; Bulk modulus;

Thin-walled pressure vessels - cylindrical and spherical vessels.

UNIT - II

INTERNAL FORCES IN BEAMS

Introduction; Diagrammatic conventions for supports,loads; Calculation of reactions, Shear force and Bending moment in beams. Shear force and Bending moment diagrams;Differential equations of equilibrium for a beam element.

UNIT - III

INORMAL STRESSES IN BEAMS

Introduction; Basic assumptions; The elastic flexure formula; application of flexure formula;

Unsymmetrical bending - Bending about both principal axes of a beam with symmetric cross section.

UNIT -IV

SHEAR STRESSES IN BEAMS

Shear flow; The shear stress formula for beams; Shear stress in beam flanges; Shear centre.

TORSION

Torsion of circular elastic bars - basic assumptions; The torsion formula, Design of circular bars in torsion for strength, Angle of twist of circular bars.

TEXT BOOKS

1.Strength of materials by R.K.Bansal

REFERENCE BOOKS

1. Engineering mechanics of solids by E.P. Popov

2.Strength of materials by S.P Timoshenko and D.H.Young

Comments

Relation between Modulus of Elasticity and Modulus of Rigidity

Modulus of Elasticity (E) It is the ratio between Normal stress to Normal strain within the elastic limit. Elastic Modulus E = Normal stress/Normal strain E = s/e Modulus of Rigidity (G) It is the ratio between Shear stress to Shear strain within the elastic limit. Rigidity Modulus G = Shear stress/ Shear strain G = Ƭ / ø Relation between Modulus of Elasticity and Modulus of Rigidity: Consider a solid cube PQRS is subjected to a shearing force F. Let Ƭ be the shear stress produced in the faces PQ and RS due to this shear force. The complementary shear stress consequently produced in the vertical faces PS and RQ is also equal to same and shown in figure as Ƭ Due to the pure shearing force, the cube is deformed PQRS to PQR'S' . The point S moved to S' and point R moved to R' as shown in fig. The shear strain = The angle of distortion ø ...

Shearing Stresses Distribution in Circular Section

Show that the shearing stress developed at the neutral axis of a beam with circular cross section is τ max = (4/3)(F/πr2). Assume that the shearing stress is uniformly distributed across the neutral axis. Solution : Let us consider the circular section of a beam as displayed in following figure. We have assumed one layer EF at a distance y1 from the neutral axis of the circular section of the beam Shear stress at a section will be given by following formula as mentioned here Where, F = Shear force (N) τ = Shear stress (N/mm2) A = Area of section, where shear stress is to be determined (mm2) ȳ = Distance of C.G of the area, where shear stress is to be determined, from neutral axis of the beam section (m) Q = A. ȳ = Moment of the whole shaded area about the neutral axis I = Moment of inertia of the given section about the neutral axis (mm4) For circular cross-section, Moment of inertia, I = ПR4/4 b = Width of the given section where shear stress is to be determined. Let us co...

PORTAL METHOD and CANTILEVER METHOD

The behavior of a structure subjected to horizontal forces depends on its height to width ratio. The deformation in low-rise structures, where the height is smaller than its width, is characterized predominantly by shear deformations. In high rise building, where height is several times greater than its lateral dimensions, is dominated by bending action. To analyze the structures subjected to horizontal loading we have two methods. Portal method and Cantilever method 1. PORTAL METHOD The portal method is an approximate analysis used for analysing building frames subjected to lateral loads such as Wind loads/ seismic forces. Since shear deformations are dominant in low rise structures, the method makes simplifying assumptions regarding horizontal shear in columns. Each bay of a structure is treated as a portal frame, and horizontal force is distributed equally among them. Assumptions in portal method 1. The points of inflection are located at the mid-height of e...

Prof.Kodali Srinivas

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