How to scientifically calculate the bearing capacity parameters of silicon carbide rollers?

Silicon carbide (SiC) rollers are the core load-bearing components of kilns in the ceramic, metallurgical, photovoltaic and other industries. Their load-bearing capacity directly affects production safety and efficiency. Correctly calculating their load-bearing capacity parameters helps optimize the design, extend service life and avoid the risk of breakage. The following are key calculation methods:

1. Determine the mechanical properties of the material

The load-bearing capacity of silicon carbide rollers depends first on their material properties, including:

• Flexural strength (usually 100-400 MPa, depending on the sintering process)

• Elastic modulus (about 400-450 GPa)

• Thermal expansion coefficient (4.5×10⁻⁶/℃)

These parameters need to be obtained through test reports provided by the manufacturer or laboratory tests.

2. Calculate the load capacity under static load

The rollers in the kiln are mainly subjected to uniform loads (such as the weight of the ceramic body) and concentrated loads (such as the pressure at the supporting point). The maximum allowable load (F) can be estimated by the simply supported beam formula:

$$F=\frac{2\times \mathrm{<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">s</span></span>}<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">\times </span></span>I}{L<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">\times </span></span>\mathrm{<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">and</span></span>}}$$

in:

• σ : Material flexural strength (MPa)

• I : Moment of inertia of the area (for round bars,$\mathrm{<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">I</span></span>}<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">=</span></span>\frac{\mathrm{<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">p</span></span>}{d}^4}{64}$, d is the diameter)

• L : Roller support span (mm)

• y : distance from the edge of the section to the neutral axis ($\mathrm{<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">and</span></span>}<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">=</span></span>\mathrm{<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">d</span></span>}\mathrm{/}\mathrm{<span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;"><span\; style="margin:\; 0px;\; padding:\; 0px;\; box-sizing:\; border-box;\; vertical-align:\; inherit;">2</span></span>}$）

Example : A SiC roller with a diameter of 30 mm and a span of 2 m (σ=200 MPa) has a theoretical bearing capacity of approximately 120 kg (needs to be adjusted in combination with the safety factor).

3. Dynamic load and thermal stress correction

• Effect of high temperature : Under long-term high temperature, the strength of silicon carbide will decrease (refer to the high temperature strength curve, such as the strength attenuation of about 20% at 1400°C).

• Thermal shock : Rapid cooling and heating can cause internal stress, requiring the allowable load to be reduced by 10-30%.

4. Safety factor selection

In industrial applications, a safety factor ≥ 3 is recommended to account for material defects, installation errors or accidental impacts.

5. Practical verification

The theoretical values can be further verified by simulating the force distribution through finite element analysis (FEA) or performing physical load tests (such as three-point bending tests).

Conclusion

Scientific calculation of the bearing capacity of silicon carbide rollers requires comprehensive consideration of material properties, structural parameters and working conditions. Reasonable design can significantly increase the life of rollers, reduce kiln failures, and ensure efficient production.