A Model for Automatic Control of Vibratory Plate Compactor
of the most Application of automatic control into compaction eglenineering works. This isoduel to problem compared with other machines used in civil g the difficulties in getting proper feedback, consisting of a transfer to the compactor and information on the state of the soil being just under compaction. The The paper presents an approach to this difficult and practically ti p ort nt p h have been discussion contains evaluation of several different responses possibility of a1 in information on g used so far in compaction analysis. compactor without Additionally, involving mathematical model of soil is mechanical behaviour of c pacto considered.
Dynamic Compaction Analysis
A simplified model based on the one‐dimensional wave equation, which accounts for the interaction of the pounder and the soil, and the propagation of stress wave in the soil during the dynamic compaction of loose granular soil is presented. The soil beneath the pounder is represented by a nonlinear soil column, while the surrounding soil is represented by a series of springs and dashpots. The spring simulates the dynamic soil stiffness and the dashpot accounts for the radiation damping effect. The input soil parameters of the model can be determined in the laboratory or estimated from correlations with measured field data. In spite of the various simplifying assumptions in the model and the predictive method, computed results, such as pounder penetration and degree and depth of improvement, show an encouraging measure of agreement with available field measurements from two dynamic compaction projects. The proposed model is potentially useful for the analysis of dynamic compaction of loose granular soil.
Fatigue effects on the coordinative pattern during cycling: kinetics and kinematics evaluation.
The aim of the present study was to analyze the net joint moment distribution, joint forces and kinematics during cycling to exhaustion. Right pedal forces and lower limb kinematics of ten cyclists were measured throughout a fatigue cycling test at 100% of PO(MAX). The absolute net joint moments, resultant force and kinematics were calculated for the hip, knee and ankle joint through inverse dynamics. The contribution of each joint to the total net joint moments was computed. Decreased pedaling cadence was observed followed by a decreased ankle moment contribution to the total joint moments in the end of the test. The total absolute joint moment, and the hip and knee moments has also increased with fatigue. Resultant force was increased, while kinematics has changed in the end of the test for hip, knee and ankle joints. Reduced ankle contribution to the total absolute joint moment combined with higher ankle force and changes in kinematics has indicated a different mechanical function for this joint. Kinetics and kinematics changes observed at hip and knee joint was expected due to their function as power sources. Kinematics changes would be explained as an attempt to overcome decreased contractile properties of muscles during fatigue.