The assembly defines the baseline mechanical system.
The spindle contains the shaft as the moving element, radial aerostatic bearings, a double-acting aerostatic thrust bearing, a radial gas-turbine drive and the grinding tool as the process interface.
It is classified as non-contact because rotor support and torque generation are achieved without mechanical contact: through pressurised gas films in the bearings and gas flow in the turbine drive.
Four functional elements define the structural model.
- Moving element: shaft, rotor mass distribution and tool interface.
- Non-contact supports: radial and thrust bearing geometry, clearance, load capacity, stiffness, damping, flow and locations.
- Drive unit: torque source, configuration and position in the assembly.
- Tool interface: grinding tool, process loads, interface geometry and required accuracy.
The assembly drawing defines their physical arrangement. The structural model defines their functional and parametric relationships.
Bearing modifications must be evaluated at spindle-system level.
An increase in local stiffness or load capacity can change the complete rotor–support system. The consequences may appear in shaft displacement, support reactions, natural frequencies, critical-speed separation and unbalance response.
- Support layout changes the effective boundary conditions of the shaft.
- Bearing coefficients depend on the selected operating state and coordinate basis.
- Shaft geometry and mass distribution determine how the support state enters the modes.
- The drive and tool interface define additional loads, moments and interface constraints.
Engineering sequence from structural prototype to system verification.
This system-level design sequence was subsequently implemented in the AURA workflow. The bearing remains a calculation object; the spindle remains the engineering system that must satisfy the process requirements.
How AURA uses the structural prototype.
The resulting support state is first screened in the shaft-line rotor model and can then continue into targeted external CFD or structural FE when higher-fidelity evidence can change the system decision.