A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Active control of buckling using piezo-ceramic actuators
Although structural materials such as steel are very strong in many ways, they have one severe flaw, they are flexible. When long, thin members are loaded in compression beyond a certain critical load, this flexibility leads to buckling, in which the member suddenly flexes due to the applied load. Buckling is a sudden failure that occurs without warning and often leads to complete structural collapse, requiring that very large safety factors (load reductions of 20 till 100 times) be incorporated into designs in order to ensure that buckling does not occur. Active control allows members to be loaded beyond their critical buckling load by using sensors to detect the onset of buckling motion and applying actuation forces to restore the member to the undeflected position. In theory, a perfectly straight, unperturbed column will never buckle, and can support loads well above the critical buckling load. The key idea that makes active control of buckling attractive is that if the onset of buckling is detected very early, while the column is still nearly straight, the column will still be supporting almost all of the applied load. Thus the control forces do not need to support the applied load directly but keep the deflections of a column small. Experiments conducted using a composite steel/piezo-ceramic column achieved a factor of 5.6 increase in load-bearing capability through active stabilization of the first two uniaxial buckling modes. In addition, a small-scale railroad-style truss bridge was constructed to demonstrate that multiple actively stabilized compressive members may be incorporated into a compound structure. An overview of the experimental results is given, design criteria for actively stabilized members are suggested and potential industrial applications are discussed.
Active control of buckling using piezo-ceramic actuators
Although structural materials such as steel are very strong in many ways, they have one severe flaw, they are flexible. When long, thin members are loaded in compression beyond a certain critical load, this flexibility leads to buckling, in which the member suddenly flexes due to the applied load. Buckling is a sudden failure that occurs without warning and often leads to complete structural collapse, requiring that very large safety factors (load reductions of 20 till 100 times) be incorporated into designs in order to ensure that buckling does not occur. Active control allows members to be loaded beyond their critical buckling load by using sensors to detect the onset of buckling motion and applying actuation forces to restore the member to the undeflected position. In theory, a perfectly straight, unperturbed column will never buckle, and can support loads well above the critical buckling load. The key idea that makes active control of buckling attractive is that if the onset of buckling is detected very early, while the column is still nearly straight, the column will still be supporting almost all of the applied load. Thus the control forces do not need to support the applied load directly but keep the deflections of a column small. Experiments conducted using a composite steel/piezo-ceramic column achieved a factor of 5.6 increase in load-bearing capability through active stabilization of the first two uniaxial buckling modes. In addition, a small-scale railroad-style truss bridge was constructed to demonstrate that multiple actively stabilized compressive members may be incorporated into a compound structure. An overview of the experimental results is given, design criteria for actively stabilized members are suggested and potential industrial applications are discussed.
Active control of buckling using piezo-ceramic actuators
Verhindern der Biegung einer druckbelasteten Tragsäule unter Verwendung von piezokeramischen Stellgliedern als Lageregler
Berlin, A.A. (author)
1995
14 Seiten, 7 Bilder, 12 Quellen
Conference paper
English
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