O que é uma célula de carga de extensômetro

In industrial and technological fields, precise measurement of force and weight is crucial. The Strain Gauge Load Cell, a key sensor that converts mechanical quantities such as force or weight into electrical signals, has become one of the most common and important measurement tools in industrial applications. With its high precision and wide range of applications, this sensor plays a critical role in providing reliable measurement data across various industries. Its operation principle and structure are highly sophisticated, utilizing the strain effect to convert small mechanical deformations into detectable electrical signals.

Strain Gauge Load Cells Princípio de funcionamento

The Strain Gauge Load Cell core principle is based on the strain effect, which states that the electrical resistance of a conductor material changes when it undergoes deformation. In simple terms, when the sensor is subjected to external force, the elastic element inside the sensor undergoes small deformations. This deformation causes the strain gauges attached to it to deform as well, leading to changes in resistance. By measuring these small changes in resistance, the applied force can be calculated.

Strain Gauge Load Cells Working Process

1. Applying External Force: When the object to be measured applies a force, the elastic element inside the load cell deforms slightly.
2. Strain Gauge Deformation: Since the strain gauges are tightly attached to the elastic element, they deform as the elastic element deforms (either stretching or compressing).
3. Resistance Change: The deformation of the strain gauges leads to changes in their length and cross-sectional area, which in turn causes changes in resistance. Resistance increases when stretched and decreases when compressed.
4. Wheatstone Bridge: To measure such small changes in resistance, multiple strain gauges (usually four) are connected in a Wheatstone bridge circuit. This bridge amplifies the resistance change, making it easier to detect.
5. Output Voltage: When no external force is applied, the bridge is in a balanced state, and the output voltage is zero. When external force deforms the elastic element, it causes a change in the strain gauge resistance, unbalancing the bridge and generating a weak voltage signal proportional to the applied force.
6. Signal Processing: This weak voltage signal is then amplified and digitized through amplifiers and an analog-to-digital converter (A/D converter), ultimately converting into a force or weight reading that can be displayed or used by a control system.

Strain Gauge Load Cells Structure

The Strain Gauge Load Cell consists mainly of two core components:

1. Elastic Element (Flexure Element): This is the metal body of the sensor, typically made from high-strength alloy steel or aluminum. The design of the elastic element is highly precise, allowing it to undergo small, predictable elastic deformations when external force is applied, while being able to return to its original shape once the force is removed.
2. Strain Gauges: These are the sensing elements that convert the mechanical deformation of the elastic element into an electrical signal. Strain gauges are typically made from fine metal wires or metal foils arranged in a grid pattern and securely bonded to the elastic element.

Strain Gauge Load Cells Aplicações

Due to their high precision, stability, and wide range of measurement, strain gauge load cells have been widely used across many industries. Some of the common application areas include:

1. Industrial Weighing Systems: Such as truck scales, vehicle scales, hanging scales, packaging scales, and batching scales, which are used for precise measurement and control of material weights in logistics and warehousing industries.
2. Material Testing Machines: Used for precise measurement of material mechanical properties in tension, compression, bending, and fatigue tests, providing accurate data for research and material testing.
3. Process Control: Applied in the monitoring of tank, bin, and reactor levels or weights to enable automated control in various manufacturing processes.
4. Aeroespacial: Used for stress, strain, and fatigue testing of aircraft wings, engines, and structural components, ensuring the safety and durability of aviation structures.
5. Medical Equipment: Used in medical weight scales and rehabilitation devices, providing accurate physiological data to assist doctors in diagnosis and treatment.
6. Civil Engineering: Applied in stress monitoring and health assessment of large structures like bridges, dams, and buildings, ensuring the safety and stability of construction projects.
7. Automotive Industry: Used in crash testing, suspension system testing, and engine torque measurement to improve vehicle safety and performance.

Differences Between Different Types of Load Cells

Conclusão

Strain Gauge Load Cells, with their high precision, stability, and versatile applications, have become indispensable components in various industries. Whether used in industrial production for precise weighing or in research, medical, and aerospace fields for accurate measurements, they have proven to be reliable and crucial in providing critical data. With ongoing technological advancements, the applications of strain gauge load cells will continue to expand, offering more precise and dependable measurement solutions for industries worldwide.