Method and sheet like sensor for measuring stress distribution

A sensor system for measuring stress distribution comprising:

• a grid of members which change in resistance when subjected to strain, the members intersecting at internal nodes and intersecting at boundary nodes at the periphery of the grid defining a plurality of legs;
• and
• an analyzer electrically connected to the boundary nodes and configured to:
• a) measure the resistances of the legs between the boundary nodes,
• b) estimate the resistances of all of the legs,
• c) calculate the resistances of all of the legs based on the measured resistance of the legs between the boundary nodes and the estimated resistances of all of the legs,
• d) compare the calculated resistances of the legs between the boundary nodes with the measured resistances of the legs between the boundary nodes,
• e) based on the comparison, re-estimate the resistances of all of the legs, and
• f) iteratively repeat steps c)-e) until the measured resistances of the legs between the boundary nodes converge to the calculated resistances of legs between the boundary nodes to thus accurately determine the resistances of the legs between or connected to the internal nodes.

A sensor system comprising:

• a grid including internal nodes and boundary nodes at the periphery of the grid defining a plurality of legs;
• and
• an analyzer electrically connected to the boundary nodes and configured to:
• a) measure a characteristic of the legs between the boundary nodes,
• b) estimate the same characteristic of all of the legs,
• c) calculate the same characteristic of all of the legs base on the measured characteristic of the legs between the boundary nodes and the estimated characteristic of all of the legs,
• d) compare the calculated characteristic of the legs between the boundary nodes with the measured characteristic of the legs between the bound nodes,
• e) based on the comparison, re-estimate the resistances of all of the legs;
• and
• f) iteratively repeat steps c)-e) until the measured characteristic of the legs between the boundary nodes converge to the calculated characteristic of the legs between the boundary nodes.

A method for determining impedances in a grid of leg impedances, the legs intersecting at boundary nodes at the periphery of the grid and intersecting at internal nodes within the grid, the method comprising:

• a) measuring the resistances of the legs between the boundary nodes,
• b) estimating the resistances of all of the legs,
• c) calculating the resistances of all of the legs based on the measured resistances of the legs between the boundary nodes and the estimated resistances of all of the legs,
• d) comparing the calculated resistances of the legs between the boundary nodes with the measured resistances of the legs between the boundary nodes,
• e) based on the comparison, re-estimating the resistances of all of the legs, and
• f) iteratively repeating steps c)-e) until the measured resistances of the legs between the boundary nodes converge to the calculated resistances of the legs between the boundary nodes to thus accurately determine the resistance of the legs between or connected to the internal nodes.

A sheet-like sensor for measuring stress distribution comprising:

• a grid of wires which change in resistance when subjected to strain, the wires intersecting at internal nodes and intersecting at boundary nodes at the periphery of the grid defining a plurality of legs, the wires encapsulated in an encapsulation material;
• and
• an analyzer connected to the boundary nodes and configured to:
• a) measure the resistances of the legs between the boundary nodes,
• b) estimate the resistances of all of the legs,
• c) calculate the resistances of all of the legs based on the measured resistances of the legs between the boundary nodes and the estimated resistances of all of the legs,
• d) compare the calculated resistances of the legs between the boundary nodes with the measured resistances of the legs between the boundary nodes,
• e) based on the comparison, re-estimate the resistances of all of the legs;
• and
• f) iteratively repeat steps c)-e) until the measured resistances of the legs between the boundary nodes converge to the calculated resistances of the legs between the boundary nodes to thus accurately determine the resistances of the legs between or connected to the internal nodes.

A method of measuring stress distribution in a grid of wires which change in resistance when subjected to strain, the wires intersecting at internal nodes and intersecting at boundary nodes at the periphery of the grid defining a plurality of legs, the method comprising:

• a) measuring the resistances of the legs between the boundary nodes,
• b) estimating the resistances of all of the legs,
• c) calculating the resistances of all of the legs based on the measured resistances of the legs between the boundary nodes and the estimated resistances of all of the legs,
• d) comparing the calculated resistances of the legs between the boundary nodes with the measured resistances of the legs between the boundary nodes,
• e) based on the comparison, re-estimating the resistances of all of the legs;
• and
• f) iteratively repeating steps c)-e) until the measured resistances of the legs between the boundary nodes converge to the calculated resistances of the legs between the boundary nodes to thus accurately determine the resistances of the legs between or connected to the internal nodes.

An analysis method comprising:

• a) measuring the resistances of legs of a grid between boundary nodes of said grid;
• b) estimating the resistances of all of the legs;
• c) calculating the resistances of all of the legs based on the measured resistances of the legs between the boundary nodes and the estimated resistances of all of the legs;
• d) comparing the calculated resistances of the legs between the boundary nodes with the measured resistances of the legs between the boundary nodes;
• e) based on the comparison, re-estimating the resistances of all of the legs;
• and
• f) iteratively repeating steps c)-e) until the measured resistances of the legs between the boundary nodes converge to the calculated resistances of the legs between the boundary nodes.

An analysis method comprising:

• a) measuring a characteristic of legs of a grid between boundary nodes of said grid;
• b) estimating the same characteristic of all of the legs;
• c) calculating the same characteristic of all of the legs based on the measured characteristic of the legs between the boundary nodes and the estimated characteristic of all of the legs;
• d) comparing the calculated characteristic of the legs between the boundary nodes with the measured characteristic of the legs between the boundary nodes,
• e) based on the comparison, re-estimating the characteristic of all of the legs;
• and
• f) iteratively repeating steps c)-e) until the measured characteristic of the legs between the boundary nodes converge to the calculated characteristic of the leg between the boundary node.

A sheet-like sensor for measuring stress distribution comprising:

• a grid of members which change in resistance when subjected to strain, the members intersecting at internal nodes and intersecting at boundary nodes at the periphery of the grid defining a plurality of legs;
• and
• an analyzer electrically connected only to the boundary nodes and configured to calculate any change in resistance in all of the legs based solely on the measured resistance of the legs between the boundary nodes, said analyzer configured to:
• a) measure the resistances of the legs between the bound nodes,
• b) estimate the resistances of all of the legs,
• c) calculate the resistances of all of the legs based on the measured resistances of the legs between the boundary nodes and the estimated resistances of all of the legs,
• d) compare the calculated resistances of the legs between the boundary nodes with the measured resistances of the legs between the boundary nodes,
• e) based on the comparison, re-estimate the resistances of all of the legs, and
• f) iteratively repeat steps c)-e) until the measured resistances of the legs between the boundary nodes converge to the calculated resistances of the legs between the boundary nodes to thus accurately determine the resistances of the legs between or connected to the internal nodes.

A sheet-like sensor for measuring stress distribution comprising:

• a grid of members which change in resistance when subjected to strain, the members intersecting at internal nodes and intersecting at boundary nodes at the periphery of the grid defining a plurality of legs;
• and
• an analyzer connected only to the boundary nodes, said analyzer configured to:
• a) measure the resistances of the legs between the boundary nodes,
• b) estimate the resistances of all of the legs,
• c) calculate the resistances of all of the legs based on the measured resistances of the legs between the boundary nodes and the estimated resistances of all of the legs,
• d) compare the calculated resistances of the legs between the boundary nodes with the measured resistances of the legs between the boundary nodes,
• e) based on the comparison, re-estimate the resistances of all of the legs, and
• f) iteratively repeat steps c)-e) until the measured resistances of the legs between the boundary nodes converge to the calculated resistances of the legs between the boundary nodes to thus accurately determine the resistances of the legs between or connected to the internal nodes.