Light intensity strain analysis

Claim 2

A strain analysis process for determining the strain field of a structure specimen comprising: providing a transparent structural substrate specimen, depositing a relatively thin metallic film on one surface of said specimen, measuring the optical properties of total and central image transmittance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image transmittance thereof, whereby the changes in transmittance optical properties of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 3

A strain analysis process for determining the strain field of a structure specimen comprising: providing a transparent structural substrate specimen, depositing a relatively thin metallic film on one surface of said specimen, measuring the optical properties of total and central image transmittance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image transmittance thereof, whereby the changes in transmittance optical properties of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 4

A strain analysis process for determining the strain field of a structure specimen comprising: providing a transparent structural substrate specimen, depositing a relatively thin metallic film on one surface of said specimen, measuring the optical properties of total and central image transmittance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image transmittance thereof, whereby the changes in transmittance optical properties of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 5

The process of claim 1 wherein said structure specimen is a low modulus material and the metallic film deposited thereon is in the range of 20-500 angstroms thick.

Claim 6

The process of claim 1 wherein said metallic coating is selected from the group of metals consisting of indium, aluminum, gold, silver and copper.

Claim 7

A strain analysis process for determining the strain field of a transparent polymeric material comprising: providing a transparent polymeric material specimen, depositing a metallic film coating in the range of 20-500 angstroms thickness on said specimen, measuring the optical properties of total and central image transmittance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image transmittance thereof, whereby the changes in total and central image transmittance optical property characteristics of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 8

A strain analysis process for determining the strain field of a transparent polymeric material comprising: providing a transparent polymeric material specimen, depositing a metallic film coating in the range of 20-500 angstroms thickness on said specimen, measuring the optical properties of total and central image transmittance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image transmittance thereof, whereby the changes in total and central image transmittance optical property characteristics of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 9

A strain analysis process for determining the strain field of a low modulus transparent polymeric material comprising: providing a transparent polymeric material specimen, subjecting said specimen to a predetermined stress load and while said specimen is stressed, depositing a relatively thin coating of a metal selected from the group consisting of indium, aluminum, gold, silver and copper on one surface of said specimen, measuring the optical property characteristics of total and central image transmittance of said stressed film coated specimen, gradually decreasing the stress load on said specimen while continuously measuring the changes in total and central image transmittance property characteristics until all stress load is removed, whereby the changes in total and central image transmittance optical property characteristics of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 10

A strain analysis process for determining the strain field of a low modulus transparent polymeric material comprising: providing a transparent polymeric material specimen, subjecting said specimen to a predetermined stress load and while said specimen is stressed, depositing a relatively thin coating of a metal selected from the group consisting of indium, aluminum, gold, silver and copper on one surface of said specimen, measuring the optical property characteristics of total and central image transmittance of said stressed film coated specimen, gradually decreasing the stress load on said specimen while continuously measuring the changes in total and central image transmittance property characteristics until all stress load is removed, whereby the changes in total and central image transmittance optical property characteristics of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 11

A strain analysis process for determining the strain field of an opaque high modulus structure specimen comprising: providing an opaque high modulus structure specimen, coating a thin layer of low modulus elastomeric material on said specimen, depositing a relatively thin metallic film selected from the group of metals consisting of indium, aluminum, gold, silver and copper on the exposed surface of said low modulus layer, measuring the optical properties of total and central image reflectance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image reflectance thereof, wheReby the changes in total and central image reflectance optical properties of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 12

A strain analysis process for determining the strain field of an opaque high modulus structure specimen comprising: providing an opaque high modulus structure specimen, coating a thin layer of low modulus elastomeric material on said specimen, depositing a relatively thin metallic film selected from the group of metals consisting of indium, aluminum, gold, silver and copper on the exposed surface of said low modulus layer, measuring the optical properties of total and central image reflectance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image reflectance thereof, wheReby the changes in total and central image reflectance optical properties of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 13

A strain analysis process for determining the principle directions and signs of local strains of a structural specimen comprising: providing a low modulus structural substrate specimen, depositing a metallic film in the range of 20-500 angstroms thickness and selected from the group of metals consisting of indium, aluminum, gold, silver and copper on one surface of said specimen, subjecting said film coated specimen to biaxial stress loads of sufficient magnitude as to cause multiple microscopic wrinkles and microfractures in said film, microscopically examining the stress loaded film coated specimen, whereby the microscopic wrinkle and microfractures which develop are indicative of the directions and signs of the local principle strains of said structural specimen.

Claim 14

A strain analysis process for determining the principle directions and signs of local strains of a structural specimen comprising: providing a low modulus structural substrate specimen, depositing a metallic film in the range of 20-500 angstroms thickness and selected from the group of metals consisting of indium, aluminum, gold, silver and copper on one surface of said specimen, subjecting said film coated specimen to biaxial stress loads of sufficient magnitude as to cause multiple microscopic wrinkles and microfractures in said film, microscopically examining the stress loaded film coated specimen, whereby the microscopic wrinkle and microfractures which develop are indicative of the directions and signs of the local principle strains of said structural specimen.

Claim 15

The method of claim 7 wherein the microscopic wrinkle and microfracture patterns form a diffraction grating whereby the orientation of collimated light diffracted thereby is indicative of the directions and signs of the local principal strains of said structural specimen.

Claim 16

The method of claim 7 and further including the step of measuring the wrinkle lines per unit length and the density of microfractures at the load values of interest whereby the density of microfractures and wrinkle line elements are indicative of the strain field of said structural specimen.

Claim 17

A strain analysis process for determining the strain field of a structure specimen comprising: providing a transparent structural substrate specimen, depositing a relatively thin metallic film on one surface of said specimen, measuring the optical properties of total and central image reflectance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image reflectance thereof, whereby the changes in total and central image reflectance optical properties of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 18

A strain analysis process for determining the strain field of a structure specimen comprising: providing a transparent structural substrate specimen, depositing a relatively thin metallic film on one surface of said specimen, measuring the optical properties of total and central image reflectance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image reflectance thereof, whereby the changes in total and central image reflectance optical properties of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 19

The process of claim 10 wherein said structure specimen is a low modulus material and the metallic film deposited thereon is in the range of 20-500 angstroms thick and is selected from the group of metals consisting of indium, aluminum, gold, silver and copper.

Claim 20

A strain analysis process for determining the strain field of a transparent polymeric material comprising: providing a transparent polymeric material specimen, depositing a metallic film in the range of 20-500 angstroms thickness on said specimen, measuring the optical properties of total and central image reflectance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image reflectance thereof, whereby the changes in total and central image reflectance optical property characteristics of said film coated specimen are indicative of the strain field of said structural specimen.

Claim 21

A strain analysis process for determining the strain field of a transparent polymeric material comprising: providing a transparent polymeric material specimen, depositing a metallic film in the range of 20-500 angstroms thickness on said specimen, measuring the optical properties of total and central image reflectance of said film coated specimen, subjecting said film coated specimen to biaxial stress loads while continuously measuring the optical properties of total and central image reflectance thereof, whereby the changes in total and central image reflectance optical property characteristics of said film coated specimen are indicative of the strain field of said structural specimen.