Strain Gauge Rosette: Definition and Limitations

By BYJU'S Exam Prep

Updated on: September 25th, 2023

A Strain Gauge Rosette is a type of sensor used to measure a material’s strain. It consists of multiple strain gauges arranged in a specific pattern, usually in a rosette shape. The gauges are typically bonded to the surface of the material being tested, and their electrical resistance changes as the material are deformed, allowing for precise measurement of the strain.

Strain Gauge Rosette PDF

Strain gauge rosettes are commonly used in various aerospace, automotive, and civil engineering applications. They are particularly useful when the strain is not uniform across a surface, as the multiple gauges in a rosette allow strain measurement in multiple directions. Strain gauge rosettes are also useful in high-stress environments, providing more accurate readings than a single strain gauge.

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What is Strain Gauge Rosette?

The Strain Gauge Rosette sensors measure the strain on a material. It comprises several strain gauges arranged in a certain pattern, typically in the shape of a rosette. Strain gauge rosettes are focused on the GATE ME exam as well. These gauges are normally attached to the surface of the material under test, and their electrical resistance varies as the material deforms, allowing for exact strain measurement.

The multiple gauges in a rosette allow for the measurement of strain in multiple directions, making it particularly useful in situations where the strain is not uniform across a surface. These sensors are commonly used in various industries, such as aerospace, automotive and civil engineering.

Material of Strain Gauge Rosettes

Strain gauge rosettes typically comprise substrate material on which the strain gauges are bonded. The most common substrate materials used for strain gauge rosettes are metal and composite. Metal substrates, such as aluminum or steel, are often used for high-temperature and high-stress applications. They are durable and have good heat dissipation properties, which helps prevent the gauges from overheating and damaging.

Composite materials, such as fiberglass or carbon fiber, are also commonly used as substrates for strain gauge rosettes. They are lightweight and have good corrosion resistance, making them suitable for aerospace and automotive applications. They are also flexible, allowing them to conform to the shape of the measured part. The strain gauges are typically made of thin metal foil, such as nickel-chromium alloy, and bonded to the substrate using a special adhesive. The adhesive must withstand the environmental conditions of the application and maintain a good bond with the substrate.

Construction of Strain Gauge Rosettes

The construction of a strain gauge rosette typically consists of several key components: the substrate, the strain gauges, and the adhesive. The substrate is the base material on which the strain gauges are bonded. As mentioned, this can be a metal such as aluminium or steel or a composite material such as fibreglass or carbon fibre. The strain gauges are typically made of thin metal foil, such as nickel-chromium alloy. They are designed to change electrical resistance when a mechanical force is applied to them. The gauges are usually arranged in a specific pattern, such as a rosette, to measure strain in multiple directions.

The adhesive is used to bond the strain gauges to the substrate. It must withstand the application’s environmental conditions and maintain a good bond with the substrate. The adhesive is applied to the substrate in the rosette pattern, and the gauges are then placed on top and pressed into the adhesive. The adhesive is then cured, typically by heating it, to create a permanent bond. The strain gauges are typically connected to a data acquisition system by wires, which are soldered or welded to the gauges. The data acquisition system records the electrical resistance of the gauges, which can be used to calculate the strain on the material being tested. This is a basic construction of the Strain gauge rosette. The design and construction can vary depending on the application and the manufacturer.

Measurement of Strain

Strain measurement can be performed in two ways namely,

  • Direct (electrical-type gauges based on Resistive, Capacitive, Inductive or Photoelectric principles)
  • Indirect (optical methods, such as Photoelasticity, the Moiré technique, or Holographic interferometry)

The majority of strain gauges are foil types, available in a wide choice of shapes and sizes to suit a variety of applications. They consist of a pattern of resistive foil which is mounted on a backing material. They operate on the principle that as the foil is subjected to stress, the resistance of the foil changes in a defined way.


The strain gauge is connected to a Wheatstone Bridge circuit with a combination of four active gauges (full bridge), two gauges (half bridge) or less commonly, a single gauge (quarter bridge). In the half and quarter circuits, the bridge is completed with precision resistors.

The complete Wheatstone Bridge is excited with a stabilised DC supply and with additional conditioning electronics, can be zeroed at the null point of measurement. As stress is applied to the bonded strain gauge, a resistive change takes place and unbalances the Wheatstone Bridge.

This results in a signal output, related to the stress value. As the signal value is small, (typically a few millivolts) the signal conditioning electronics provides amplification to increase the signal level to 5 to 10 volts, a suitable level for application to external data collection systems such as recorders or PC Data Acquisition and Analysis Systems.


Most manufacturers of strain gauges offer extensive ranges of different patterns to suit a wide variety of applications in research and industrial projects.

They also supply all the necessary accessories including preparation materials, bonding adhesives, connection tags, cable, etc. The bonding of strain gauges is a skill and training courses are offered by some suppliers. There are also companies which offer bonding and calibration services, either as an in-house or on-site service.

Rosette Strain Gage

  • A strain gage only measures strain in one direction, in order to get principal strains, it is necessary to use a strain rosette
  • A strain rosette is a cluster of 3 strain gages oriented at different angles

A strain gage rosette is, by definition, an arrangement of two or more closely positioned gage grids, separately oriented to measure the normal strains along different directions in the underlying surface of the test part.

  • Rosettes are designed to perform a very practical and important function in experimental stress analysis.
  • Rosettes are manufactured from different combinations of grid alloy and backing material to meet varying application requirements.
  • They are also offered in a number of gage lengths, noting that the gage length specified for a rosette refers to the active length of each individual grid within the rosette.
  • To determine the three independent components of plane strain, three linearly independent strain measures are needed, i.e., three strain gages positioned in a rosette-like layout.

For example, Consider a strain rosette attached on the surface with an angle a from the x-axis. The rosette itself contains three strain gages with internal angles b and g, as illustrated on the right.


Suppose that the strain measured from these three strain gages are ea, eb, and ec, respectively.

The following coordinate transformation equation is used to convert the longitudinal strain from each strain gage into strain expressed in the xy coordinates,


Applying this equation to each of the three strain gages results in the following system of equations,


These equations are then used to solve for the three unknowns, ex, ey, and exy.


  1. The above formulas use the strain measure exy as opposed to the engineering shear strain gxy, image005. To use gxy, the above equations should be adjusted accordingly
  2. The free surface on which the strain rosette is attached is actually in a state of plane stress, while the formulas used above are for plane strain. However, the normal direction of the free surface is indeed a principal axis for strain. Therefore, the strain transform in the free surface plane can be applied.

Special Cases of Strain Rosette Layouts:

Case 1: 45º strain rosette aligned with the xy axes, i.e., α = 0º, β = γ = 45º.



Case 2: 60º strain rosette, the middle of which is aligned with the y-axis, i.e., α = 30º, β = γ = 60º.



Uses of Strain Gages:
  • Strain gages attached to Wheatstone bridges can be used for the measurement of tension, bending, and torsion.
  • In biomedical applications, strain gages can be used for determining forces in bones
  • Slightly modified strain gauges can be used for muscle contraction and blood pressure measurement.

Applications of Strain Gauge Rosettes

The Strain Gauge Rosette sensors measure the strain on a material. It is made up of numerous strain gauges arranged in a certain pattern, usually in the shape of a rosette. Strain gauge rosettes have a wide range of applications in various industries, including:

  1. Aerospace: Strain gauge rosettes measure the strain on aircraft components such as wings, fuselages, and engines. They are used to monitor the aircraft’s performance and detect any potential issues.
  2. Automotive: Strain gauge rosettes measure the strain on car components such as frames, suspension systems, and engines. They are used to monitor the car’s performance and detect any potential issues.
  3. Civil Engineering: Strain gauge rosettes are used in the construction industry to measure the strain on structures such as bridges, buildings, and dams. They are used to monitor the structures’ performance and detect any potential issues.
  4. Biomedical Engineering: They are used in biomedical engineering to measure the strain on bones and joints to study the human body’s biomechanical behaviour.
  5. Industrial: They are used in industrial applications such as monitoring the performance of machinery and detecting any potential issues, such as cracks in rotating shafts.
  6. Research: They study materials’ mechanical properties and test new designs.

These are some of the common applications of Strain gauge rosettes. Due to their ability to measure strain in multiple directions, they are versatile tools that can be used in many fields.

Limitations of Strain Gauge Rosettes

Strain gauge rosettes have limitations, including sensitivity to small strains, temperature effects, and potential for hysteresis and creep error. Improper installation and exposure to electromagnetic interference and fatigue can also impact the accuracy of measurements.

  1. Sensitivity: Strain gauge rosettes may have limited sensitivity to accurately measure small strains.

  2. Temperature Effects: Temperature changes can cause expansion or contraction of the material, affecting the measurements of strain.

  3. Hysteresis: The hysteresis error caused by the material’s nonlinear behaviour can affect the measurements’ accuracy.

  4. Creep: The material may deform over time under load, leading to errors in the strain measurements.

  5. Fatigue: Continuous exposure to high-stress levels can cause the material to fatigue, reducing its accuracy in measuring strain.

  6. Electromagnetic Interference: Electromagnetic fields can interfere with the strain gauges’ readings, leading to measurement errors.

  7. Installation: Improper installation of the strain gauges can affect their accuracy and durability.

Important GATE Notes
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Zeroth and First Laws of Thermodynamics Universal Joint
First Law of Thermodynamics Helical Gear
Triangle Law of Forces Connecting Rod
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Mechanical Energy Constant Velocity

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