Design Of Screw Jack Numerical 2 Part 2 - Design Against Static Loads - Machine Design I

TL;DR

This video discusses the design safety check for screws in machine design, considering aspects such as torsion, compression, and bending stresses.

Transcript

click the Bell icon to get latest videos from Ekeeda Hello friends welcome back to the subject of machine design 1 now we are going to do the design safety check for the selected screw in the last lecture we have derived the notations for it and we have found out different values of its dimensions so there are two aspects which we need to consider ... Read More

Key Insights

• ✊ Shear stress and compressive stress are two prominent stress types induced in a power screw.
• 📁 Bending stress should also be considered, as screws may fail under direct compression or bending.
• 🧑‍🏭 The maximum principle stress and maximum shear stress are both important factors to consider in determining screw failure, but in this case, only torsion is considered.
• ✊ By comparing allowable shear stress and induced shear stress, the safety of the power screw can be determined.

Questions & Answers

Q: What aspects are considered in the design safety check for screws?

The design safety check for screws considers torsion, compression, bending, and possible failure under combined loading conditions, such as compression and bending stress or shear stress and bending stress.

Q: How is shear stress calculated for a power screw?

Shear stress in a power screw is calculated using the standard formula derived from the torsion equation, where torsion is equal to the shear stress. By substituting the appropriate values, such as the diameter and torsion, the shear stress can be determined.

Q: What is the formula for compressive stress calculation in screws?

The formula for calculating compressive stress in screws is straightforward. After calculation, the value is typically given in units of million newtons per millimeter squared.

Q: How is bending stress evaluated in power screws?

Bending stress in power screws is evaluated using the bending equation. By substituting the values for second moment of area and bending moment, the bending stress can be calculated.

Summary & Key Takeaways

• The video covers the calculation of shear stress for a power screw, considering torsion as a failure condition.

• It also explains the calculation of compressive stress using a straightforward formula.

• The video discusses the use of the bending equation to determine bending stress in the screw and considers the possibility of the screw failing under combined loading conditions.