.pod-calculator-wrapper {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 25px;
margin-bottom: 30px;
}
.pod-calc-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 24px;
font-weight: 700;
}
.pod-input-group {
margin-bottom: 15px;
display: flex;
flex-direction: column;
}
.pod-row {
display: flex;
flex-wrap: wrap;
gap: 20px;
}
.pod-col {
flex: 1;
min-width: 250px;
}
.pod-label {
font-weight: 600;
margin-bottom: 5px;
color: #495057;
display: block;
font-size: 14px;
}
.pod-input {
width: 100%;
padding: 10px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.15s ease-in-out;
}
.pod-input:focus {
border-color: #007bff;
outline: none;
}
.pod-btn {
background-color: #007bff;
color: white;
border: none;
padding: 12px 20px;
font-size: 16px;
font-weight: 600;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 15px;
transition: background-color 0.2s;
}
.pod-btn:hover {
background-color: #0056b3;
}
.pod-result-box {
background-color: #e8f4fd;
border: 1px solid #b8daff;
border-radius: 4px;
padding: 20px;
margin-top: 25px;
display: none;
}
.pod-result-item {
display: flex;
justify-content: space-between;
align-items: center;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px solid #d6e9fc;
}
.pod-result-item:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.pod-result-label {
color: #004085;
font-weight: 600;
}
.pod-result-value {
font-weight: 700;
color: #0056b3;
font-size: 18px;
}
.pod-article {
line-height: 1.6;
color: #333;
margin-top: 40px;
}
.pod-article h2 {
color: #2c3e50;
border-bottom: 2px solid #007bff;
padding-bottom: 10px;
margin-top: 30px;
}
.pod-article h3 {
color: #495057;
margin-top: 25px;
}
.pod-tip {
background-color: #fff3cd;
border-left: 5px solid #ffc107;
padding: 15px;
margin: 20px 0;
font-size: 0.95em;
}
function calculateWearRate() {
// Get inputs
var massLoss = parseFloat(document.getElementById("pod_mass_loss").value);
var density = parseFloat(document.getElementById("pod_density").value);
var load = parseFloat(document.getElementById("pod_load").value);
var diameter = parseFloat(document.getElementById("pod_track_diameter").value);
var speed = parseFloat(document.getElementById("pod_speed").value);
var duration = parseFloat(document.getElementById("pod_duration").value);
// Validation
if (isNaN(massLoss) || isNaN(density) || isNaN(load) || isNaN(diameter) || isNaN(speed) || isNaN(duration)) {
alert("Please fill in all fields with valid numbers.");
return;
}
if (density <= 0 || load <= 0 || diameter <= 0 || speed <= 0 || duration <= 0) {
alert("Values must be greater than zero.");
return;
}
// Calculations
// 1. Calculate Volume Loss (mm³)
// Note: mg / (g/cm³) = mm³ because 1 g/cm³ = 1 mg/mm³
var volumeLoss = massLoss / density;
// 2. Calculate Sliding Distance (m)
// Circumference (m) = PI * Diameter (mm) / 1000
var circumferenceMeters = (Math.PI * diameter) / 1000;
var totalRevolutions = speed * duration;
var slidingDistance = circumferenceMeters * totalRevolutions;
// 3. Calculate Specific Wear Rate (mm³/N·m)
// k = Volume Loss / (Load * Sliding Distance)
var wearRate = volumeLoss / (load * slidingDistance);
// Display Results
document.getElementById("res_volume").innerHTML = volumeLoss.toFixed(4) + " mm³";
document.getElementById("res_distance").innerHTML = slidingDistance.toFixed(2) + " m";
// Format Wear Rate (Scientific notation is often better for very small numbers)
document.getElementById("res_rate").innerHTML = wearRate.toExponential(4);
// Show results div
document.getElementById("pod_results").style.display = "block";
}
Understanding Pin-on-Disk Wear Rate Calculation
The Pin-on-Disk test is one of the most common methods in tribology for characterizing the wear resistance of materials. It involves a stationary pin pressed against a rotating disk under a known load. By measuring how much material is lost during the test, engineers can calculate the Specific Wear Rate, a critical metric for predicting the lifespan of mechanical components.
The Specific Wear Rate Formula
The calculation is based on Archard's wear equation. The specific wear rate ($k$) represents the volume of material removed per unit of energy (Load × Distance). The standard formula used in this calculator is:
$k = \frac{V}{F \times L}$
Where:
- $k$: Specific Wear Rate ($mm^3/N\cdot m$)
- $V$: Volume of worn material ($mm^3$)
- $F$: Normal Load applied (Newtons)
- $L$: Total Sliding Distance (meters)
How to Determine Input Values
To use the calculator effectively, you need to derive the inputs from your experimental setup:
1. Volume Loss ($V$)
Directly measuring the volume of a wear scar can be difficult. It is more common to weigh the sample before and after the test to find the Mass Loss (in mg). You then divide this mass by the material's density ($g/cm^3$) to get the volume loss.
Note on Units: Since $1 g/cm^3$ is mathematically equivalent to $1 mg/mm^3$, dividing Mass (mg) by Density ($g/cm^3$) gives you the Volume directly in $mm^3$.
2. Sliding Distance ($L$)
The sliding distance is the total path length the pin travels over the disk. It is calculated using the geometry of the wear track:
- Calculate the circumference of the wear track ($C = \pi \times d$). Remember to convert the diameter from millimeters to meters.
- Multiply the rotation speed (RPM) by the test duration (minutes) to get total revolutions.
- Multiply revolutions by circumference to get the total Sliding Distance in meters.
Interpreting the Results
The resulting specific wear rate is usually a very small number, often displayed in scientific notation (e.g., $2.5 \times 10^{-5} mm^3/Nm$).
- Lower values ($< 10^{-6}$): Indicate excellent wear resistance (e.g., ceramics, hard coatings).
- Higher values ($> 10^{-4}$): Indicate severe wear or soft materials (e.g., unlubricated polymers).
Why is Wear Rate Important?
Calculating the wear rate allows engineers to compare different materials and lubricants objectively. It is essential for designing brake systems, hip implants, engine components, and manufacturing tools where durability is paramount.