# Strain Gauges Fundamentals

Strain gauges have been around for almost 80 years and continue to be key assets to measure fatigues and test materials for productivity and safety reasons. But how do I calculate material stress from strain? How can I select the right strain gauge and install it correctly? Our experts dug deep to provide you with their best answers to these and all important questions about measuring with strain gauges.

## Basics of Strain Measurements and Experimental Stress Analysis

### Strain measurement glossary

Benefit from our practical on-line glossary by looking up the most important technical terms in the field of strain measurement.

### Experimental Stress Analysis (ESA) using strain gauges

The principle of Experimental Stress Analysis (ESA) consists in using strain gauges to measure strains on a component's surface. The absolute value and direction of the mechanical stresses are determined from the measured strains and the known properties of the material (modulus of elasticity and Poisson’s ratio). These calculations are based on Hooke’s Law which applies to the elastic deformation range of linear-elastic materials. Learn more by clicking here.

### The Wheatstone bridge circuit

The Wheatstone bridge is well suited for the measurement of small changes of a resistance and is, therefore, also suitable for measuring the resistance change in a strain gauge. It is commonly known that the strain gauge transforms strain applied into a proportional change of resistance. Find more about the application of Wheatstone Bridge Circuits here.

### The reference book on Experimental Stress Analysis using strain gauges

Get a complete overview of the topic of "An Introduction into Measurements using Strain Gauges" - in Karl Hofmann's 250-page reference book.

## Selecting the Right Strain Gauges, Adhesive, Covering Agents and More

### How to select the right strain gauge

HBM offers a wide range of strain gauges suitable for almost every measuring task. But how to find the right strain gauge? Here you will get enough information to help you find the right strain gauge for your needs in an easy and straightforward way.

### How to select the right adhesive

Strain gauges are usually applied to the surface of the measurement object using adhesives. Here you can learn how to select  the correct adhesive according to the material and temperature range. This page also provides tips for preparing a measuring point to ensure good bonding for strain transfer.

### How to select the right covering agent

The quality of a measurement with strain gauges depends essentially on the type of installation and design of the measuring point. A thorough preparation of the installation surface, correct connection, and protective covering are important factors for problem-free results.

## Installation of Strain Gauges: All There is to Know

### How to prepare material for a strain gauge installation

Click here for a quick overview on how to prepare your material for an effective strain gauge installation. Apply the suggestions given by our highly-skilled experts for a successful installation on concrete, plastics, fiber-reinforced material, among others.

### How to install a strain gauge

This training video shows you all the necessary step by step for a successful strain gauge installation. No measurement skills or previous installation experience is required.

### How to weld a strain gauge

Some environments are not suitable for bonding strain gauges due to very low temperatures or excessive dust formation, e.g. on construction sites. Weldable strain gauges are the best choice for being used in this type of environments. Watch our video on how to weld your strain gauge correctly.

### Tips for installing strain gauges

In many cases, measuring strain on an object is done in a short timeframe. If the strain gauge is improperly installed, false measurements can be obtained. Watch this video to learn how to install gauges in the most effective way.

### Practical hints for the installation of strain gauges

Get a complete overview of the topic of "Practical Hints for the Installation of Strain Gages"- in Karl Hofmann's reference book.

## Reduction and Elimination of Measurement Errors

### Measurement uncertainty: less errors, better results

There are possible sources of error when strain gauges are used in experimental stress analysis. Learn how to successfully assess measurement uncertainty already in the design stage by clicking on the title above.

### Temperature effects on measurement results

Unwanted temperature effects can affect the measurement result when using strain gauges. Find practical assistance on how to minimize these effects or compensate for them entirely. Learn more by clicking on the title above.

Particularly electrical resistance changes in the cable that connects the measuring pints to the measuring device, e.g. due to temperature variations, have negative effects in the measurement. Click above to find out more.

## Acquiring Data with the Right Hardware and Software

### How to work with strain gauges in catman AP

In this tutorial you will learn how to set up strain gauge rosettes using HBM's catman®AP data acquisition software and a QuantumX MX1615 data acquisition system.

## Training, Webinars and References on Strain Measurements and Gauges

### Recorded webinars

Missed one of our live webinars? Watch our recorded webinars on strain measurements and strain gauges using the filter to select the ones that best suits your needs.

### Successful case studies and references

Get access to all the successful stories involving the use of strain gauges in a wide scope of measurement applications and projects undergone by HBM. Just select Strain Gauges in the dropdown list under Type of Sensors Used, here.