Diaphragm Mechanical Cross-Section
Mechanical Visual Signal Chain
Applied Pressure
0.00 bar
Diaphragm Deflection
0.00 mm
Mechanical Displacement
0.00 mm
Applied Pressure
0.00 bar
Center Deflection
0.00 mm
APPLIED PRESSURE
bar
PROCESS PRESSURE GAUGE
DIAPHRAGM PARAMETERS
| Trial # | Pressure (bar) | Diameter (mm) | Thickness (mm) | Material | Elastic Modulus (GPa) | Center Deflection (mm) | Sensing Range |
|---|
1
Select the desired Diaphragm Material (e.g. Stainless Steel) and inspect its Elastic Modulus (E).
2
Set the Diaphragm Diameter (range: 20 – 100 mm) using the parameter slider.
3
Set the Diaphragm Thickness (range: 0.10 – 2.00 mm). Observe how thickness affects membrane stiffness.
4
Select the required Sensing Range (0–5 bar, 0–10 bar, or 0–20 bar).
5
Set the applied pressure to 0 bar.
6
Observe the diaphragm at the Zero Reference Position (dashed orange line).
7
Increase applied pressure gradually using the pressure slider or preset buttons (2.5 bar, 5.0 bar, 7.5 bar, 10 bar).
8
Observe physical Diaphragm Deflection bending upwards from fixed boundary edges.
9
Observe the Mechanical Push Rod displacement and movement along the mechanical scale.
10
Record the pressure and center deflection readings into the Observation Table.
11
Change diaphragm thickness (e.g., increase from 0.5 mm to 1.0 mm) and observe reduced deflection.
12
Repeat the experiment for different pressure values.
13
Change diaphragm diameter and observe the strong D⁴ relationship with deflection.
14
Analyze the live Pressure vs. Deflection Graph to compare linear mechanical behavior.
What is a Diaphragm Sensing Element?
A diaphragm is a primary mechanical pressure-sensing element consisting of a thin, flexible circular membrane clamped firmly around its outer circumference.
When fluid pressure is applied to one side of the diaphragm, the pressure force causes the flexible membrane to deflect perpendicularly away from its reference zero plane.
Deflection Physics & Mechanics
For a flat circular diaphragm clamped at its outer boundary (r = R), the maximum mechanical displacement occurs at the center (r = 0) and is governed by elasticity theory:
w₀ = (3 · P · (1 - ν²) · R⁴) / (16 · E · t³)
- w₀: Center deflection (mm)
- P: Applied pressure (Pascal)
- R: Diaphragm radius (mm)
- t: Diaphragm thickness (mm)
- E: Young's Modulus of elasticity (GPa)
- ν: Poisson's ratio (~0.3 for metals)
Key Parametric Relationships
- Effect of Pressure (P): Center deflection w₀ increases linearly with applied pressure.
- Effect of Thickness (t): Deflection is inversely proportional to the cube of thickness (1 / t³). A thicker diaphragm is significantly stiffer.
- Effect of Diameter (D): Deflection increases with the 4th power of diameter (D⁴). Larger diaphragms provide much higher sensitivity for low pressure measurement.
- Effect of Material (E): Stiffer materials (higher Young's Modulus E) result in smaller mechanical displacement.