Study on the Shrinkage Error of Similar Material Simulation Experiment
Shrinkage error will impact the results obtained from the observation data when studying subsidence by the method of similar material simulation experiment. Using digital industrial close-range photogrammetry system in the experiment, high-precision observational data is collected. By comparative analysis on the subsidence of the points at different locations, we obtained the distribution law of shrinkage subsidence and horizontal movement which has great significance for the study on how to reduce the shrinkage error effectively.
Analysis of dynamic damage procedure of ground building caused by horizontal distortion
It's very serious for horizontal deformation to damage building.Based on the form of horizontal deformation and damage,the mechanics mechanism of damage to building is analyzed and the dynamic damage process of horizontal deformation is disclosed from the formation process of subsidence,relation between horizontal deformation of building and surface and advance rate of stope.
Dimensional Errors of Fixtures, Locating and Measurement Datum Features in the Stream of Variation Modeling in Machining
Machining processes are usually multi-station processes involving a large number of operations and several locating datum changes. Machining errors are thus introduced, transformed and accumulated as the workpiece is being machined. This paper introduces procedures for expressing the influence of errors in fixtures, locating datum features and measurement datum features on dimensional errors in machining. These procedures are essential in the derivation of the Stream of Variation model of dimensional machining errors using the CAD/CAPP parameters of the machining process. The linear state space form of the Stream of Variation model allows for advanced control theory achievements to be employed in formal solutions to problems in multi-station machining. Modeling procedures presented in this paper were experimentally verified in machining of an automotive cylinder head.