Method for calculating internal explosion load speed based on incremental crack growth distance of pipeline

Patent metadata

Field	Value
Publication number	US-11566987-B1
Application number	US-201916979183-A
Country	US
Kind code	B1
Filing date	Jul 22, 2019
Priority date	Jul 22, 2019
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

The present disclosure discloses a method for calculating an internal explosion load speed based on an incremental crack growth distance of a pipeline. The method includes steps of: respectively measuring at least three groups of distances between neighboring markings on forward and backward crack surfaces, and calculating the average values respectively to obtain the average incremental growth distances of forward and backward cracks; calculating the natural vibration frequency of the pipeline; and setting the ratio of backward crack speed to forward crack speed of the pipeline, then calculating the internal explosion load speed of the pipeline by a formula. The present disclosure provides a new effective method for calculating the internal explosion load speed based on the available parameters of the ruptured pipeline after explosion, which can provide a comparatively accurate estimation of internal explosion load speed, thereby providing references for inferring the explosion type occurred in the pipeline.

First claim

What is claimed is:

1. A method for calculating an internal explosion load speed based on an incremental crack growth distance of a pipeline, a crack propagating in the same direction as an explosion load being defined as a forward crack, while a crack propagating in the opposite direction to the explosion load being defined as a backward crack, and the method comprising:
step S1 of respectively measuring, from a crack initiation position, at least three groups of distances between neighboring markings on forward and backward crack surfaces along an axial direction of pipeline, and then calculating average values to obtain average incremental growth distances d 1 and d 2 of the forward and backward cracks, respectively;
step S2 of calculating a natural vibration frequency f 0 of the pipeline; and
step S3 of setting a ratio c of a backward crack speed to a forward crack speed of the pipeline, c generally ranging from 0.70 to 0.95; and calculating the internal explosion load speed D by the following formula:

D
=

d
1

⁢

d
2

⁢

f
0

(

1
+
c

)

c
⁢

d
1

-

d
2

.

2. The method for calculating an internal explosion load speed based on an incremental crack growth distance of a pipeline according to claim 1 , wherein the ratio c of the backward crack speed to the forward crack speed of the pipeline is equal to 0.90.

3. The method for calculating an internal explosion load speed based on an incremental crack growth distance of a pipeline according to claim 1 , wherein the distances between the neighboring markings on the forward and backward crack surfaces are directly measured or obtained by detecting changes of material mechanical properties along a crack path and marking positions of damages.

4. The method for calculating an internal explosion load speed based on an incremental crack growth distance of a pipeline according to claim 1 , wherein three to five groups of distances between the neighboring markings on the forward and backward crack surfaces are required, respectively.

5. The method for calculating the internal explosion load speed based on the incremental crack growth distance of the pipeline according to claim 1 , wherein for a pipeline with two ends fixed, the natural vibration frequency f 0 is calculated by the following formula:

f
0

=

1

2
⁢
π
⁢
R

⁢

E

ρ
⁡
(

1
-

v
2

)

where R is a radius of the pipeline, E is an elastic modulus of pipeline material, ρ is a density of pipeline material, and v is a Poisson's ratio of pipeline material.

Assignees

• Univ China Petroleum East China

Inventors

• Du Yang
• Jiang Wenchun
• Zhou Fan
• Zheng Jinyang
• Wang Chaojie
• Chen Guoming

Classifications

• G01N29/12

  by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)} · CPC title

• G01N3/313 Primary

  generated by explosives · CPC title

• G01M5/0033 Primary

  by determining damage, crack or wear · CPC title

• G01M5/0025

  of elongated objects, e.g. pipes, masts, towers or railways (G01M5/0058 takes precedence) · CPC title

• G06Q10/06

  Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling · CPC title