This module outlines the basic mechanics of elastic response | a physical phenomenon that
materials often (but do not always) exhibit. An elastic material is one that deforms immediately
upon loading, maintains a constant deformation as long as the load is held constant, and returns
immediately to its original undeformed shape when the load is removed. This module will also
introduce two essential concepts in Mechanics of Materials: stress and strain
After reading this chapter, you should be able to answer the following questions: What is stress, and how is it different than stressors and strains? What are the four main types of stressors? How do individuals cope with stress? How does the Type A Behavior Pattern influence the stress process? How does stress affect job performance and organizational commitment? What steps can organizations take to manage employee stress?
Soils are aggregates of mineral particles, and together with air and/or water
in the void spaces, they form three-phase systems. A large portion of the
earth’s surface is covered by soils, and they are widely used as construction
and foundation materials. Soil mechanics is the branch of engineering that
deals with the engineering properties of soils and their behavior under
Simple Stresses in Machine Parts
C H A P T E R
Simple Stresses in Machine Parts
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. Introduction. Load. Stress. Strain. Tensile Stress and Strain. Compressive Stress and Strain. Young's Modulus or Modulus of Elasticity. Shear Stress and Strain Shear Modulus or Modulus of Rigidity. Bearing Stress. Stress-Strain Diagram. Working Stress. Factor of Safety. Selection of Factor of Safety. Stresses in Composite Bars. Stresses due to Change in Temperature—Thermal Stresses.
This book is intended to supply engineering professionals and students with a comprehensive
and definitive reference to statics and dynamics of solids and structures. The book is for use
as a resource and design tool in research and development, and for use as a study guide and
learning aid in engineering education.
The book is written to meet the needs for interactive computing in technical referencing and
Load. Stress. Strain. Tensile Stress and Strain. Compressive Stress and Strain. Young's Modulus or Modulus of Elasticity. Shear Stress and Strain Shear Modulus or Modulus of Rigidity. Bearing Stress. Stress-Strain Diagram. Working Stress. Factor of Safety. Selection of Factor of Safety. Stresses in Composite Bars. Stresses due to Change in Temperature—Thermal Stresses. Linear and Lateral Strain. Poisson's Ratio. Volumetric Strain. Bulk Modulus. Relation between Bulk Modul u s a n d Yo u n g ' s Modulus. Relation between Young's Modulus and Modulus of Rigidity. Impact Stress. Resilience.
Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture.In modern materials science, fracture mechanics is an important tool in improving the mechanical performance of materials and components.
This chapter summarizes the structure of solids, including atomic bonding forces, atomic structures, crystal imperfections, slip, and mechanical strength. The section on mechanical properties and tests discusses all the hardness tests and includes a detailed explanation of the tensile test and tensile properties. The section on strength, stress, and strain
The main objective of this book is to show, in a logical sequence, a set of papers
presenting new ideas that have been the result of the great advance in the knowledge
of steel within the last few decades. Amongst the fundamental topics dealt with is the
relationship between steel's properties in terms of its structure and composition and
how this is affected by its surrounding environment (i.e. stresses, temperature, strains,
STRENGTH UNDER STATIC CIRCUMSTANCES
Charles R. Mischke, Ph.D., RE. Professor Emeritus of Mechanical Engineering Iowa State University Ames, Iowa Joseph E. Shigley Professor Emeritus The University of Michigan Ann Arbor, Michigan
12.1 PERMISSIBLE STRESSES AND STRAINS / 12.2 12.2 THEORY OF STATIC FAILURE / 12.3 12.3 STRESS CONCENTRATION / 12.7 12.4 FRACTURE MECHANICS / 12.11 12.5 NONFERROUS METALS / 12.17 12.6 STOCHASTIC CONSIDERATIONS / 12.20 REFERENCES / 12.
The medical consequences of
operating outside of the normal boundaries of a well tuned musculo-tendinous system are
also poorly understood, although clearly recognized in the persistent atrophy experienced
in microgravity despite rigorous exercise programs.
Muscle force generation is length and velocity sensitive. The process is repetitive in the
sense that muscles will always generate force based on their length-tension and forcevelocity
properties, causing tendon deformation.
Piezoelectricity from the Greek word "piezo" means pressure electricity. Certain crystalline
substances generate electric charges under mechanical stress and conversely experience a
mechanical strain in the presence of an electric field.
The piezoelectric effect was discovered in some naturally occurring materials in the 1880s.
However it was not until the Second World War that man-made polycrystalline ceramic ma‐
terials were produced that also showed piezoelectric properties.
ANORECTAL AND PELVIC FLOOR TESTS
Pelvic floor dysfunction is suggested by the inability to evacuate the rectum, a feeling of persistent rectal fullness, rectal pain, the need to extract stool from the rectum digitally, application of pressure on the posterior wall of the vagina, support of the perineum during straining, and excessive straining. These significant symptoms should be contrasted with the sense of incomplete rectal evacuation, which is common in IBS.
Velocity encoded phase-contrast magnetic resonance imaging (VE-PC MRI) is another
imaging technique used to noninvasively measure Achilles tendon strain and changes in its
force-displacement relationship concomitant with chronic unloading and subsequent
recuperation. This technique will be reviewed in terms of its ability to quantify the Achilles
tendon Young’s modulus (MPa) from a stress-strain curve.
In the range of high strain rates, the mechanical behaviour of materials is characterized by an increased
strain rate sensitivity, by increasing effects of mass inertia forces and by the adiabatic character of the
For the relation between stress, strain and strain rate, empirical formulae are now mostly replaced by
material laws based on structural mechanical models, whose parameters are to be determined by adequate
systematic methods. Also special effects such as the influence of strain rate on...
The use of fibre optic sensors in structural health monitoring has rapidly accelerated in recent years. By embedding fibre optic sensors in structures (e.g. buildings, bridges and pipelines) it is possible to obtain real time data on structural changes such as stress or strain. Engineers use monitoring data to detect deviations from a structure’s original design performance in order to optimise the operation, repair and maintenance of a structure over time.
It is a curve in which unit load or stress is plotted against unit elongation, technically known as strain. O– A represents the stress is directly proportional to strain, and point A is known proportional limit. Point B represents elastic limit beyond which the material will not return to its original shape when unloaded but will retain a permanent deformation called permanent set.
Torsional Shear Stress. Shafts in Series and Parallel. Bending Stress in Straight Beams. Bending Stress in Cur ved Beams. Pr incipal Stresses and Principal Planes. Determination of Principal Stresses for a Member Subjected to Biaxial Stress. Application of Principal Stresses in Designing Machine Members. Theories of Failure under Static Load. Maximum Principal or Nor mal Stress Theor y (Rankine’s Theory). Maximum Shear Stress Theory (Guest’s or Tresca’s Theory). Maximum Principal Strain Theor y (Saint Venant’s Theory). Maximum Strain Energy Theory (Haigh’s Theory).