# Mechanical Engineering

## Worm Gear Efficiency

Most gear types have efficiencies in a fairly tight range.  On the other hand, worm gear efficiency can vary greatly.  A large portion of losses in a worm gear set is due to the sliding friction between the worm and gear. The sliding friction is dependent on the worm lead angle, λ and the coefficient …

## Using the Combined Stress Tool

In bodies under plane stress, MEboost’s combined stress tool calculates various stresses that allow for comparison to a yield strength in uniaxial tension.  These stresses are used in conjunction with failure theories to determine suitability of a design. The tool calculates the following: Von Mises stress In-plane principal stresses Maximum shear stresses (in-plane and out …

## Maximum Shear Stress for Plane Stress

When a body is under plane stress,  determining maximum shear stress can depends on the stress state.  In this article we’ll look at the conditions that determine whether in-plane shear stress or out of plane shear stress is the maximum. Plane Stress Consider an element where applied stresses are confined to the xy plane. In …

## Using the MEboost Shaft Design Tool

MEboost’s shaft design tool allows for comprehensive analysis of shaft designs.  The shaft design tool allows for the following analysis: Static stress. Deflection and slope. Stress life fatigue analysis for infinite life. Static and fatigue stress concentrations. Critical speed calculation. For more general information on shaft design, see shaft design considerations. Shaft Design Tool Coordinate …

## Failure Theories for Ductile Materials

In this article, we will discuss two of the common failure theories for ductile materials: the maximum shear stress theory and the maximum distortion energy theory.  We’ll also discuss why the maximum normal stress theory should never be used with ductile materials. When we have a situation with combined stress, we need to find an …

## Shaft Design Considerations

Shaft design is a common task in machines because shafts are everywhere.  While common, the amount of thought that goes into it can be surprisingly large.  In this article we’ll look at the various considerations to create a shaft design. Things to Check in a Shaft Design Static stress  The shaft must withstand stress that …

## Beam Diagrams in MEboost

Beam diagrams are an easy way to understand how loading of a beam translates into bending stress.  If you add a deflection diagram, there is even more information that is readily available.  MEboost has a tool that can create shear, moment and deflection diagrams. Assumptions and Load Types The tool requires that the beam is …

## Using Mohr’s Circle for Plane Strain

Mohr’s circle for plane strain can be used for determining principal strains in a body under plane strain.  This article will cover the basics of Mohr’s circle in plane strain, and how it is easily created using MEboost. MEboost also handles bodies under plane stress.  To learn about this scenario, refer to the article on …

## Pressure Head Conversion

MEboost has a pressure head conversion tool that converts pressure to head or head to pressure.  We’ll cover the underlying theory of pressure head conversion and how this conversion is easily done in MEboost. Conversion Equation Head is the fluid height equivalent to pressure.  In other words, head is the height of a fluid column …

## System and Pump Curves

The system curve tool in MEboost can generate a fluid system curve approximation as well as up to four pump curves on the same chart.  You can also generate a combined pump curve where pumps are either in parallel or series.  In this article, we’ll show how calculations are made and how to generate the …