# Measurements and Analysis for Mechanical Engineers

Lead Author(s): **Bridget Smyser**

Student Price: **Contact us to learn more**

An online textbook geared toward mechanical engineers that teaches experimental design, data analysis, uncertainty concepts, and key measurement techniques.

# Table of Contents

Chapter 1: Introduction to Measurements

How and why we measure

Measurement systems

Variables

Units and Standards

Image sources

References

Chapter 2: Instrument Characteristics

What do we need to know about sensors?

Accuracy and precision

Demystifying specification sheets

Sensitivity and common errors

Types of Instruments

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References

Chapter 3: Calibration and Standards

Standards

Basic theory of calibration

Calibration methods for common measurements

Calibration for pressure measurement

Calibration for temperture measurement

Calibration for strain, mass, and load measurement

Calibration for pH measurement

Calibration for sound measurement

Calibration for flow rate measurement

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References

Chapter 4: Design of Experiments

Big picture of Design of Experiments

Parameter Design

Examining the need for the experiment

Defining the objectives for the experiment

Determining what you want to measure

System and Tolerance Design

Identifying the important variables

Designing the experiment

Performing the experiments

Data Reduction Design

Analyzing the results

Acting on the results

Reporting the results

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References

Chapter 5: Uncertainty

How close can we get?

Design stage uncertainty

Advanced stage uncertainty

Multiple measurement analysis

Error propagation

Reducing and eliminating errors

Summary

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References

Chapter 6: Statistical Data Analysis

Introduction to statistical measurement theory

Infinte statistics and the normal distribution function

Histograms

Finite statistics

Comparing samples using t-tests

Two-tailed t-tests

One tailed t-tests

t-tests between two samples

Data analysis in Microsoft Excel

Analysis of variance (ANOVA)

Correlation analysis

Testing for normality

Comparing histograms

Normal probability plots

Chi-squared analysis for goodness of fit

Number of data points needed for significant results

Identifying outliers

Summary

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References

Chapter 7: Dynamic Measurements

General model for measurement system behavior

Zero order systems

First order systems

Step function input

Pulsed input

Ramp input

Wave function input

Second order systems

Step function input

Wave function input

Special case: Using system behavior to study heat transfer

Summary

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References

Chapter 8: Electrical Measurements and Signal Processing

Basic definitions

Signal characteristics

Periodic signals and Fourier analysis

Sampling theory

Useful circuit concepts

Amplifiers

Filters

Special purpose circuits

Errors in electrical measuremetns

Electrical measurement devices

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References

Chapter 9: Strain and Related Measurements

Review of stress-strain concepts

Relating strain to electrical resistance

Wheatstone bridge circuits for strain measurements

Quarter bridge circuits

Half bridge circuits

Full bridge circuits

Strain gauge specifications

Practical considerations for strain gauges

Applications of strain gauges

Summary

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References

Chapter 10: Temperature and Related Measurements

What is temperature?

Errors in temperature measurement

Methods for measuring temperature

Thermal expansion measurements

Thermoelectric measurements

Thermal resistance measurements

Thermal radiation measurements

Measuring thermal and transport properties

Thermal conductivity

Viscosity

Diffusion coefficients

Summary

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References

Chapter 11: Pressure and Related Measurements

Pressure scales and units

Types of pressure instruments

Hydrostatic pressure instruments

Aneroid pressure instruments

Static calibration

Dynamic pressure measurements in flowing fluids

Fluid flow over objects

Transmission effects in dynamic pressure measurements

Summary

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References

Chapter 12: Fluid Flow Measurement

Air flow measurement

Thermal anemometry

Doppler anemometry

Particle image velocimetry

Mass flow measurement

Volumetric flow rate measurement

Differential pressure meters

Turbine flow meters

Rotameters

Drag based meters

Electromagnetic flow meters

Ultrasonic flow meters

Calibration of flow meters

Practical considerations for flow measurements

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References