A stepped steel shaft, shown below, is used in a spur gear reducer. The shaft is subjected to a constant axial stress (A=40 MPa), a constant bending moment that results in a variable stress (M=60 MPa) due to loads by bearings and gears, and a steady torque (T=80 MPa). However, these stress values do not take into account stress concentration factors. The shaft has a D=45 mm, d=30 mm, and r=6 mm, resulting in ki,bend=1.34, Kraxial 1.48, and k₁,tor 1.2. The shaft is made of steel with S,=1006 MPa, S,=648 MPa, and H₂=229. The size of the shaft results in a gradient factor of CG=0.9. The shaft has a fine-ground finish. A 90% reliability is required. Verify the stress concentration factors are correct for this shaft geometry. Calculate the safety factor relative to infinite life (106 cycles). If the safety factor is less than one (i.e., shaft fails), find the number of cycles to failure.

Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
icon
Related questions
icon
Concept explainers
Question
1) A stepped steel shaft, shown below, is used in a spur gear reducer. The shaft is subjected to a constant axial stress (A=40 MPa), a constant bending moment that results in a variable stress (M=60 MPa) due to loads by bearings and gears, and a steady torque (T=80 MPa). However, these stress values do not take into account stress concentration factors. The shaft has a D=45 mm, d=30 mm, and r=6 mm, resulting in \(k_{t,bend}=1.34\), \(k_{t,axial}=1.48\), and \(k_{t,torsion}=1.2\). The shaft is made of steel with \(S_u=1006\) MPa, \(S_y=648\) MPa, and \(H_B=229\). The size of the shaft results in a gradient factor of \(C_g=0.9\). The shaft has a fine-ground finish. A 90% reliability is required. Verify the stress concentration factors are correct for this shaft geometry. Calculate the safety factor relative to infinite life (\(10^6\) cycles). If the safety factor is less than one (i.e., shaft fails), find the number of cycles to failure.

**Diagram Explanation:**
- The diagram shows a stepped shaft with two different diameters, \(D\) and \(d\).
- The shaft is subjected to a bending moment \(M\) at both ends and a torque \(T\).
- There are forces \(A\) applied axially at the center of the larger diameter section.
- The radius \(r\) of the fillet between the two diameters is indicated.
- The visual aids support understanding of the various forces and geometries impacting the shaft's stress analysis.
Transcribed Image Text:1) A stepped steel shaft, shown below, is used in a spur gear reducer. The shaft is subjected to a constant axial stress (A=40 MPa), a constant bending moment that results in a variable stress (M=60 MPa) due to loads by bearings and gears, and a steady torque (T=80 MPa). However, these stress values do not take into account stress concentration factors. The shaft has a D=45 mm, d=30 mm, and r=6 mm, resulting in \(k_{t,bend}=1.34\), \(k_{t,axial}=1.48\), and \(k_{t,torsion}=1.2\). The shaft is made of steel with \(S_u=1006\) MPa, \(S_y=648\) MPa, and \(H_B=229\). The size of the shaft results in a gradient factor of \(C_g=0.9\). The shaft has a fine-ground finish. A 90% reliability is required. Verify the stress concentration factors are correct for this shaft geometry. Calculate the safety factor relative to infinite life (\(10^6\) cycles). If the safety factor is less than one (i.e., shaft fails), find the number of cycles to failure. **Diagram Explanation:** - The diagram shows a stepped shaft with two different diameters, \(D\) and \(d\). - The shaft is subjected to a bending moment \(M\) at both ends and a torque \(T\). - There are forces \(A\) applied axially at the center of the larger diameter section. - The radius \(r\) of the fillet between the two diameters is indicated. - The visual aids support understanding of the various forces and geometries impacting the shaft's stress analysis.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 4 images

Blurred answer
Knowledge Booster
Combined Loading
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.
Similar questions
Recommended textbooks for you
Elements Of Electromagnetics
Elements Of Electromagnetics
Mechanical Engineering
ISBN:
9780190698614
Author:
Sadiku, Matthew N. O.
Publisher:
Oxford University Press
Mechanics of Materials (10th Edition)
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:
9780134319650
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Thermodynamics: An Engineering Approach
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:
9781259822674
Author:
Yunus A. Cengel Dr., Michael A. Boles
Publisher:
McGraw-Hill Education
Control Systems Engineering
Control Systems Engineering
Mechanical Engineering
ISBN:
9781118170519
Author:
Norman S. Nise
Publisher:
WILEY
Mechanics of Materials (MindTap Course List)
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:
9781337093347
Author:
Barry J. Goodno, James M. Gere
Publisher:
Cengage Learning
Engineering Mechanics: Statics
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:
9781118807330
Author:
James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:
WILEY