Methods for forewarning of critical condition changes in monitoring civil structures

A sensor module for forewarning of a critical event in a larger-than-human-size physical structure, the sensor module comprising:

• means for mounting the sensor module on the physical structure,
• wherein the sensor module further comprises a multi-axis accelerometer producing accelerometer data for a plurality of axes of motion at a location on the physical structure;
• wherein the sensor module further comprises a processor that executes program instructions for computing mechanical power data (P) from the accelerometer data;
• wherein the processor computes a composite measure of dissimilarity (Ci) from normalized measures of dissimilarity for distribution functions derived from a phase space for a plurality of sets of mechanical power data;
• wherein the processor computes a forewarning of an impending critical event based on either one of a 1) a selected number of occurrences of the composite measure of dissimilarity (Ci) above the forewarning threshold or 2) after a selected number of occurrences of composite measure of dissimilarity (Ci) above a failure value threshold;
• and
• wherein the processor causes transmission of a forewarning signal of the impending critical event to a human observer, through one or more of a visual signal, an audible signal or a tangible signal.

A method for monitoring structural integrity of a physical structure, the method comprising:

• sensing mechanical vibrations at a plurality of locations in the structure with a respective plurality of sensors each including a tri-axial accelerometer mounted on the structure for providing data;
• converting tri-axial acceleration data into mechanical power (P) data representative of hysteresis strain energy at the plurality of locations on the structure;
• collecting the mechanical power (P) data at a single processing device;
• processing the mechanical power (P) data within the single processing device to provide a failure forewarning threshold of an impending failure of the structure based on a number of occurrences of the mechanical power data exceeding the failure forewarning threshold over a predetermined sampling time;
• and
• wherein the forewarning signal is provided to a human observer through a visual, audible or tangible signal.

A computer system for forewarning of a critical event in a larger-than-human-size physical structure, the system comprising:

• a plurality of sensor units mounted on the physical structure, each including a tri-axial accelerometer and each producing data for a plurality of respective locations on the physical structure;
• wherein the sensor units each include a radio transmitter for periodically transmitting radio signals carrying the accelerometer data representative of mechanical vibrations from the respective locations;
• and
• a network gateway receiver receiving the radio signals from the sensor units and converting the radio signals to data for transmission over a wide area network;
• a host computer receiving the accelerometer data transmitted through the wide area network;
• wherein the host computer executes program instructions for computing vibration mechanical power data from multiple axes of accelerometer data for each respective sensor;
• and
• providing a forewarning signal of an impending critical event to a human observer, through a visual, audible or tangible signal.