US 12,298,279 B1 · Testing method for layered strength of Roebel single-strands

Abstract

A testing method for layered strength of Roebel single-strands is provided, which relates to the field of material strength testing technologies. The testing method includes: preparing multiple Roebel single-strands as multiple testing samples; preparing multiple anvil heads, and welding the multiple anvil heads and the multiple testing samples in one-to-one correspondence to obtain multiple samples for anvil tensile testing; performing a tensile test on each sample for anvil tensile testing based on a set temperature and a set test position, and calculating peak load data of each sample for anvil tensile testing in the tensile test; calculating strength values of the multiple Roebel single-strands based on the peak load data of each sample for anvil tensile testing, and fitting the strength values based on a Weibull distribution function to obtain strength statistical characteristics; and calculating strength degradation data of each of the multiple Roebel single-strands based on the strength statistical characteristics.

A testing method for layered strength of Roebel single-strands, comprising:

step 1, obtaining a rare earth barium copper oxide (REBCO) superconducting tape, and cutting the REBCO superconducting tape based on preset sample geometric data using a laser marking machine to obtain multiple Roebel single-strands as multiple testing samples;
step 2, preparing multiple anvil heads, and welding the multiple anvil heads and the multiple testing samples in one-to-one correspondence to obtain multiple samples for anvil tensile testing;
step 3, performing a tensile test on each of the multiple samples for anvil tensile testing based on a set temperature and a set testing position, and calculating peak load data of each of the multiple samples for anvil tensile testing in the tensile test;
step 4, calculating strength values of the multiple Roebel single-strands based on the peak load data of each of the multiple samples for anvil tensile testing, and fitting the strength values based on a Weibull distribution function to obtain strength statistical characteristics;
and
wherein specific calculation formulas for fitting the strength values based on the Weibull distribution function are expressed as follows:
F
⁢
(
σ
)
=
1
-
exp
[
-
(
σ
-
γ
α
)
β
]
;
R
⁢
(
σ
)
=
1
-
F
⁡
(
σ
)
;
where F(σ) represents the Weibull distribution function, α represents a scale parameter, β represents a shape parameter, γ represents a position parameter, exp represents a natural exponential function, σ represents the strength value of each of the multiple Roebel single-strands, and R(σ) represents a reliability function;
step 5, calculating strength degradation data of each of the multiple Roebel single-strands under different temperatures and different positions based on a relative error formula and the strength statistical characteristics;
wherein specific calculation formulas (1)-(4) are expressed as follows:
Degradation
⁢
(
Temperature
)
=
σ
⁡
(
RT
,
case
)
-
σ
⁡
(
77
⁢
K
,
case
)
σ
⁡
(
RT
,
case
)
;
(
1
)
Degradation
⁢
(
RT
,
Cutting
)
=
σ
⁡
(
RT
,
Uncut
)
-
σ
⁡
(
RT
,
case
)
σ
⁡
(
RT
,
Uncut
)
;
(
2
)
Degradation
⁢
(
77
⁢
K
,
Cutting
)
=
σ
⁡
(
77
⁢
K
,
Uncut
)
-
σ
⁡
(
77
⁢
K
,
case
)
σ
⁡
(
77
⁢
K
,
Uncut
)
(
3
)
Degradation
⁢
(
Temperature
&
⁢
Cutting
)
=
σ
⁡
(
RT
,
Uncut
)
-
σ
⁡
(
77
⁢
K
,
case
)
σ
⁡
(
RT
,
Uncut
)
;
(
4
)
wherein case represents a cutting state, Uncut represents an uncut REBCO superconducting tape, RT represents a room temperature, Cutting represents that a corresponding degradation degree is related to the cutting state of the REBCO superconducting tape, Temperature represents that a corresponding degradation degree is related to a temperature change factor;
Degradation( ) represents a degradation degree of the strength value of the Roebel single-strand, σ( ) represents a strength value in a temperature and a cutting state;
the formula (1) represents a degradation degree of the strength value of the Roebel single-strand under 77 Kelvin degrees (K) relative to the strength value of the Roebel single-strand under the room temperature, the formula (2) represents a degradation degree of the strength value of the Roebel single-strand under the room temperature relative to the strength value of the uncut REBCO superconducting tape under the room temperature, the formula (3) represents a degradation degree of the strength value of the Roebel single-strand under the 77 K relative to the strength value of the uncut REBCO superconducting tape under the 77 K, and the formula (4) represents a degradation degree of the strength value of the Roebel single-strand under the 77 K relative to the strength value of the uncut REBCO superconducting tape under the room temperature.

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Testing method for layered strength of Roebel single-strands

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Testing method for layered strength of Roebel single-strands

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Abstract

Claims7