The vibration amplitudes and the forces transmitted to the supporting medium can become the governing factor of the foundation of these machines.
In other words, in the numerical model, when the maximum allowable displacement of the machine foundation is consistently applied to the foundation, it showed that the stress of about 160 kPa might be additionally generated to the pile head.
The displacement of the spread foundation along the machine driving direction is shown in Fig. 9.
In consideration of the dynamic load additionally generated, the design of the machine foundation is performed in the course of the following two steps.
It was thought that the design concepts of the machine foundation, assuming that the additional dynamic load due to machine vibration equals to 50% of the static load in current code, is excessively conservative.
Firstly, calculate the natural frequency and displacement of the machine foundation system subjected to the vibration load by dynamic load to avoid resonance, and design to satisfy the allowable displacement given from the machine manufacturer.
Next, the strength, stability and ground bearing capacity of the Machine foundation based on static load are evaluated, and in this case, the pseudo-static design considering the additional dynamic load is made up.
The allowable bearing capacity of a pile calculated by the model tests was considered as a working load, and after loading the working load to the single pile by the numerical analysis, the dynamic numerical analysis that applies the vibration of the machine foundation was performed.
Monitoring technologies related to the thermal error study of heavy-duty CNC machine tools are important foundation of the research on the machine tool thermal error mechanism and the establishment of a thermal error prediction model.
Description of the machine.
