worcester polytechnic instituteusers.wpi.edu/~cfurlong/es2502/lect14/lect14.pdf · mechanical...
TRANSCRIPT
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Mechanical Engineering Department
WORCESTER POLYTECHNIC INSTITUTEMECHANICAL ENGINEERING DEPARTMENT
STRESS ANALYSISES-2502, D’2020
17 April 2020
We will get started soon...
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Mechanical Engineering Department
STRESS ANALYSISES-2502, D’2020
WORCESTER POLYTECHNIC INSTITUTEMECHANICAL ENGINEERING DEPARTMENT
We will get started soon...
Lecture 14: Unit 6: tension/compression of slender
longitudinal bars: stress concentrations
17 April 2020
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Mechanical Engineering Department
Instructor: Cosme FurlongHL-152
(774) 239-6971 – Texting WorksEmail: cfurlong @ wpi.edu
http://www.wpi.edu/~cfurlong/es2502.html
General information
Teaching Assistant: Zachary ZolotarevskyEmail: zjzolotarevsky @ wpi.edu
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Mechanical Engineering Department
Stress concentrations
Ripping open candy wrap with the help of
stress concentration
Stress
concentrations
appear here
Zigzag edges added to
amplify appliedstresses
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Mechanical Engineering Department
Stress concentrations: stress “flow”
Reducing stress
concentration:
rounding edges
Stress concentration on:
sharp edgesReducing stress concentrations
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Mechanical Engineering Department
Designing to minimize stress concentrations
Initial design Improved design
Modifications to reduce stress concentrations at a sharp corner
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Mechanical Engineering Department
Stress concentrationsAxially loaded component with a hole: stress concentration factor
avg
max
KStress concentration factor:
Stresses
distribution
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Mechanical Engineering Department
Stress concentrationsAxially loaded component with a hole: stress concentration factor
𝑃 = න𝜎 𝑑𝐴
A @ a-a
Internal balancing
force at a-a
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Mechanical Engineering Department
Stress concentration factorAxially loaded component with a hole
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Mechanical Engineering Department
Stress concentrationsAxially loaded component with edges: stress concentration factor
avg
max
KStress concentration factor:
Stresses
distribution
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Mechanical Engineering Department
Stress concentrationsAxially loaded component with edges: stress concentration factor
𝑃 = න𝜎 𝑑𝐴
A @ a-a
Internal balancing
force at a-a
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Mechanical Engineering Department
Stress concentration factorAxially loaded component with edges
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Mechanical Engineering Department
Axial load: example O
The A-36 steel plate has a thickness of 12 mm. If there are shoulder
fillets at B and C, and Allow = 150 MPa, determine the maximum axial
load P that it can support. Calculate its elongation, neglecting the effect
of the fillets.
Approach:
1) Determine stress
concentration factors
2) Compute maximum
load
3) Compute elongation
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Mechanical Engineering Department
Inelastic axial deformationPlastic deformations
Model: elastic perfectly
plastic behavior
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Mechanical Engineering Department
Inelastic axial deformationPlastic deformations
Distribution of internal stresses
as load increases
(a)
Elastic
deformations(b)
Elastic + plastic
deformations
(c)
Plastic
deformations
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Mechanical Engineering Department
Reading assignment
• Chapters 3 and 4 of textbook
• Review notes and text: ES2001, ES2501
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Mechanical Engineering Department
Homework assignment
• As indicated on webpage of our course