engineering mechanics statics - meriam and kraige (5th ed)engineering mechanics statics - meriam and...

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Strength of Materials(ceng 1002) Semester II 2008

Introduction

specimen in tensile test (ultimate strength), imwf Stuttgart

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Strength of MaterialsMechanics of MaterialsMechanics of Solids

from rigid to deformable bodies �

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

stress

Cutting plane � inner actionequilibrium at particle

stress

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Stress

F F

F F

F

stress σ = F / A [kN/cm²]

example: suspended rod

- cross section area A [cm²]

- Force F [kN]

cutting planeinner actionequilibrium at particle

σ

F

A

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Strain

F

2F

2F

example: suspended rod

-Length L-Elongation ∆L

L L

∆L2=2∆L1

strain ε = ∆L / L

F

F

L

∆L1

strain εproportional to stress σ

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Hooke’s Law

linear equation : σ = Eε

E = Young�s Modulus

strain ε

stress σ[kN/m²]

gradient E [kN/m²]

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Hooke’s Law

Example: Bungee Cable

- Stress Analysis

- Serviceability

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

stress-strain diagram of mild steelaxial loadingtensile test

determination oftensile strengthand Young�s Modulus

area of plasticity

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

ε

σductile material brittle material

ε

σ

tensile test

image of failure, compression test

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

deflection due to loading

strain

stre

ss

specimen in tensile test (ultimate strength), imwf Stuttgart

Material Properties

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

Concrete specimen in compression test

free blocked

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Deflection due to condition of loading

tension compression bending torque shear

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

Timber

perpendiculartensile stress due to shrinkage

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

Timber

orthotropic material behaviour

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

cycling curves for material creepe.g. synthetics, textiles Danzer, S.18

time

time

time

time

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

Steeltime

time

time

time

deflection due to temperature (fire exposure) Brandschutzatlas

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Properties

Steel deflection due to temperature (fire exposure) Brandschutzatlas

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Stability

Buckling of columnsEuler Formula

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Stability

Buckling of columns

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Stability

Buckling of columns

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Concept of Design

load assumption : safety factor

material strength : reduction factor

stress analysis : design stress < allowable stress (stability)

serviceability : design deflection < limit deflection

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Unexpected loads

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Design Project “Bottle Bubble” Example: from an unknown material to construction

University of Karlsruhe, 2005

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Material Behaviour - determining the Elastic Modulus

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Calculation

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Lectures: Monday 8:15 � 10:00 a.m. Room No4

Karsten Schlesier

Tutorials: Friday 8:15 � 11:40 a.m. Room No4

Mesgana Seyoum

Consultation: Thursday 4:00 � 6:00 p.m. Room 211

Karsten Schlesier

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Final Exam14.07.2008mo16

07.07.2008mo15

Workshop30.06.2008mo14

Lab Session 223.06.2008mo13

Buckling Analysis616.06.2008mo12

Stability of Compression Members609.06.2008mo11

Compound Stresses 502.06.2008mo10

Torsion426.05.2008mo9

Mid-Semester Exam19.05.2008mo8

Lab Session 112.05.2008mo7

Deflection of Beams305.05.2008mo6

Bending of Beams328.04.2008mo5

Strain - Axial Load221.04.2008mo4

Stress - Axial Load114.04.2008mo3

Introduction to SOM07.04.2008mo2

Course Information04.04.2008fr1

ContentChapterDatedayweek

Calender Semester II 2008

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Course Outline

1 Stress – Axial LoadsNormal Stress, Shearing Stress, Transformation of Stress, Concept of Design

2 Strain – Axial LoadsStrain, Stress-Strain Diagram, Hooke�s Law, Deflection under Axial Load, Material Properties

3 Bending of BeamsStress due to pure Bending, Shearing Stress in Beams, Moment of Inertia, Stress Distribution, Deflection of Beams, Design of Beams

4 TorsionMoment of Torsion, Shearing Stresses and Deformations of Circular Shafts

5 Analysis of plane StressCompound Stresses, Combined Stresses, Transformation of Stress, Mohr�s Circle

6 Stability of Compression MembersEuler Formula, Buckling Load, Buckling Analysis

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

Assessment / Requirements

Minimum of 75% attendance during lecture hours and tutorials, 100% attendance during practical work sessions (except for unpredicted mishaps) � watch notice for further details.

Quota of Total Course Credit: 40% mid-semester examination40% final-semester examination20% assignments, practical workshop

Literature

Popov, E.P., Mechanics of Materials Beer and Johnson, Mechanics of Materials, 2001Gere and Timoshenko, Mechanics of Materials, 1990

E-learning Platform

www.elboon.net (elearning board online) � under construction!www.ocw.mit.edu MIT open courseware � Solid Mechanics

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil EngineeringStrength of Materials

ADDIS ABABA UNIVERSITYFaculty of Technology

Department ofCivil Engineering

G. Galileo