Method and device for testing a material sample in a standard test for inplane fracture toughness evaluation

Patent metadata

Field	Value
Publication number	US-10690575-B2
Application number	US-201916502568-A
Country	US
Kind code	B2
Filing date	Jul 3, 2019
Priority date	Jun 15, 2017
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A method of testing a material sample of a type used in a wall of a structure in a standard test for in-plane fracture toughness evaluation. The method comprises obtaining a sample having a lateral length no larger than a thickness of the wall of the structure, shaping the sample to have (a) a bottom surface, (b) a profiled top surface having a central notch, (c) a first coupling feature on a first side of the central notch, and (d) a second coupling feature on a second side of the central notch, assembling a test specimen which increases the width of the sample beyond the lateral width by coupling a first lateral extension to the first coupling feature and a second lateral extension to the second coupling feature, and applying a standard fracture toughness test to the so-assembled test specimen and sample to evaluate the fracture toughness of the sample.

First claim

What is claimed is:

1. A method of testing a material in a standard test for in-plane fracture toughness evaluation, the material sample of a type used in a wall of a structure, the method comprising:
obtaining a sample of the wall of the structure;
shaping the sample into a notched component, the notched component including a flat bottom surface having a thickness dimension equal to a thickness of the wall of the structure, and a profiled top surface, the profiled top surface having a central notch oriented perpendicular to a plane of the bottom surface to define a crack, a first socket on a first side of the central notch, and a second socket on a second side of the central notch;
assembling a test specimen which increases an effective thickness of the sample beyond the thickness of the bottom surface of the notched component by coupling a first lateral extension to the first socket and a second lateral extension to the second socket of the notched component;
applying a standard fracture toughness test to the so-assembled test specimen in order to evaluate the fracture toughness of the material in an in-plane direction by creating a bending moment that opens the crack defined by the central notch; and
machining the notched component such that the central notch is oriented to open in a S-L direction in a standard fracture toughness test,
wherein the crack in the central notch includes a first section of rectangular cross section having a first width and a distinct second section having a second width that is smaller than the first width, and wherein the bending moment opens the crack by increasing the first and second widths.

2. The method of claim 1 , further comprising forming the first and second lateral extensions such that a sum of the lengths of the first and second lateral extensions and the thickness of the notched component is as great or greater than 4.5 times the width of the notched component as measured from the bottom surface to a tip of the profiled surface.

3. The method of claim 1 , wherein the first and second sockets are symmetrical about the central notch.

4. The method of claim 1 , wherein the first and second sockets are asymmetrical about the central notch.

5. The method of claim 1 , wherein the standard fracture toughness test applies force to the bottom surface of the notched component.

6. The method of claim 1 , wherein the first and second sockets are elbow-shaped notches.

7. The method of claim 1 , wherein the structure as a thickness ranging from about 5 mm to about 70 mm.

8. The method of claim 1 , wherein the first and second lateral extensions have a length (L) that is set according to the following inequality
2 L+T≥ 4.5 W

in which T is the thickness of the sample and W is the width of the notched component.

9. An apparatus for testing a material used in a wall of a structure for fracture toughness, the apparatus comprising:
a notched component made from a sample of the material of the structure shaped to have (a) a bottom surface having a width equal to a thickness of the wall of the structure, (b) a profiled top surface, the profiled top surface having a central notch that defines a crack, (c) a first socket on a first side of the central notch, and (d) a second socket feature on a second side of the central notch;
a first lateral extension coupled to the first socket of the notched component; and
a second lateral extension coupled to the second socket of the notched component,
wherein the first and second lateral extensions extend an effective width of the notched component to provide an assembled test specimen of sufficient length to be used in a standard fracture toughness test, and
wherein the central notch of the notched component is oriented to open in a S-L direction in a standard fracture toughness test,
wherein the crack in the central notch includes a first section of rectangular cross section having a first width and a distinct second section of having a second width that is smaller than the first width, and wherein a bending moment created by the standard fracture toughness test tends to open the crack by increasing the first and second widths.

10. The apparatus of claim 9 , wherein the first and second lateral extensions are formed such that a sum of the lengths of the first and second lateral extensions and the thickness of the notched component is as great or greater than 4.5 times the width of the notched component as measured from the bottom surface to a tip of the profiled surface.

11. The apparatus of claim 9 , wherein the structure has a thickness ranging from about 5 mm to about 70 mm.

12. The apparatus of claim 11 , wherein the pipe structure is made of X65 steel.

Assignees

• Saudi Arabian Oil Co

Inventors

• Traidia Abderrazak
• Chatzidouros Elias
• Jouiad Mustapha

Classifications

• G01N2203/0298

  Manufacturing or preparing specimens · CPC title

• G01N2203/027

  Specimens with holes or notches · CPC title

• G01N2203/0066

  Propagation of crack · CPC title

• G01N2203/0064

  Initiation of crack · CPC title

• G01N2001/2886

  Laser cutting, e.g. tissue catapult · CPC title