added max_rpm example

examples/max_rpm.rs

@@ -0,0 +1,52 @@
+use std::{f64::consts::PI, f64::consts::TAU};
+use units::{
+    dimensions::{Density, Frequency, Length, Pressure, Speed},
+    prefixes::{Deci, Mega},
+    units::{density::KgPerCubicMeter, Meters, MetersPerSecond, Pascals, Rpm},
+};
+
+pub fn speed_to_rpm(tip_speed: Speed, radius: Length) -> Frequency {
+    tip_speed / (TAU * radius)
+}
+
+#[derive(Copy, Clone, Debug)]
+pub struct Flywheel {
+    tensile_strength: Pressure,
+    density: Density,
+    radius: Length,
+    thickness: Length,
+}
+
+impl Flywheel {
+    pub fn steel(radius: Length, thickness: Length) -> Self {
+        Self {
+            tensile_strength: Pressure::new::<Mega<Pascals>>(700.0),
+            density: Density::new::<KgPerCubicMeter>(7850.0),
+            radius,
+            thickness,
+        }
+    }
+    pub fn wood(radius: Length, thickness: Length) -> Self {
+        Self {
+            tensile_strength: Pressure::new::<Mega<Pascals>>(105.0),
+            density: Density::new::<KgPerCubicMeter>(700.0),
+            radius,
+            thickness,
+        }
+    }
+    pub fn max_velocity(&self) -> Speed {
+        Speed::new::<MetersPerSecond>(
+            ((self.tensile_strength * 2.0 * self.thickness)
+                / (self.density * PI.powf(2.0) * self.radius.square()))
+            .val::<units::units::MetersPerSqTime>()
+            .powf(0.5),
+        )
+    }
+}
+
+fn main() {
+    let steel = Flywheel::steel(Length::new::<Meters>(0.5), Length::new::<Deci<Meters>>(1.0));
+    let max_rpm = speed_to_rpm(steel.max_velocity(), steel.radius);
+    println!["{steel:?}"];
+    println!["{}", max_rpm.val::<Rpm>()];
+}