Energy-based material design methods for designing protective panels against specific-sized hails, protective panels and protection systems
AssigneeNingbo University
InventorLuoyu Roy Xu
Life of this patent
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Abstract
Soft material design methods for developing protective panels against a hail with a diameter of more than 25 mm are provided, wherein the protective panel comprises a soft material layer. The methods comprise: selecting a material for the soft material layer, wherein the material has a Young's modulus Esm in a range of 1 MPa to 150 MPa, preferably 5 MPa to 100 MPa; and determining a minimum thickness Tsm of the soft material layer based on the size of a hail and the material properties of the soft material and other materials inside the protective panel. A protection system that includes these protective panels covers a whole vehicle or some fragile parts on the ground.
Claims12
A method of making a protective panel against hail with a radius equal to or smaller than a predetermined value R, wherein the protective panel comprises a soft material layer, the method comprising:
- selecting a material for the soft material layer, wherein the material of the soft material layer has a Young's modulus Esm in a range of 1 MPa to 150 MPa, and the material has a linear elastic deformation characteristic or a nonlinear elastic deformation characteristic;
- and
- producing a protective panel having the soft material layer with a minimum thickness Tsm calculated based on the predetermined value R, mechanical properties of the soft material layer and other materials in the same protective panel,
- wherein the step of producing the protective panel having the soft material layer with the minimum thickness Tsm comprises;
- calculating Tsm using Equation 1:
- T
- sm
- =
- (
- 15
-
- W
- 8
- ·
- R
-
- E
- sm
- )
- 2
- /
- 5
- when the material of the soft material layer has the linear elastic deformation characteristic, wherein W is kinetic energy of a pellet of hail having a radius of the predetermined value R, and Esm is the Young's modulus of the soft material layer;
- or
- calculating Tsm using Equation 2:
- W
- =
- 8
- 1
-
- 5
-
- R
-
- E
- s
-
- m
-
- ε
- p
-
- l
- 5
- /
- 2
-
- T
- s
-
- m
- 5
- /
- 2
- +
- 1
- 2
-
- π
-
- R
-
- σ
- p
-
- l
- (
- ε
- limit
- 2
- -
- ε
- p
-
- l
- 2
- )
-
- T
- s
-
- m
- 2
- when the material of the soft material layer has the nonlinear elastic deformation characteristic, wherein W is kinetic energy of a pellet of hail having a radius of the predetermined value R, Esm is the Young's modulus of the soft material layer, σpl is a plateau strength of the soft material layer, εpl is a plateau strain of the soft material layer, εlimit is a compressive strain limit of the soft material layer, and εlimit has a value of 0.5 to 0.6.
A method of making a protective panel against hail with a radius equal to or smaller than a predetermined value R, wherein the protective panel comprises a soft material layer, the method comprising:
- selecting a material for the soft material layer, wherein the material of the soft material layer has a Young's modulus Esm in a range of 1 MPa to 150 MPa, and the material has a linear elastic deformation characteristic;
- producing a protective panel having the soft material layer with a minimum thickness Tsm calculated based on the predetermined value R, mechanical properties of the soft material layer and other materials in the same protective panel;
- and
- wrapping a fabric sheet around the soft material layer, wherein the fabric sheet has a tensile strength of more than 500 MPa and a fracture strain of more than 5%,
- wherein the step of producing the protective panel having the soft material layer with the minimum thickness Tsm comprises:
- calculating Tsm using Equation 3:
- W
- =
- E
- fb
-
- A
- fb
-
- T
- sm
- 4
- 4
-
- L
- 3
- +
- 8
- 15
-
- R
-
- E
- sm
-
- T
- sm
- 5
- /
- 2
- wherein W is kinetic energy of a pellet of hail having a radius of the predetermined value R, Efb is a Young's modulus of the fabric sheet, Afb is a cross-sectional area of the fabric sheet, Esm is the Young's modulus of the soft material layer, and 2L is a length of the soft material layer.
A method of making a protective panel against hail with a radius equal to or smaller than a predetermined value R, wherein the protective panel comprises a soft material layer, the method comprising:
- selecting a material for the soft material layer, wherein the material of the soft material layer has a Young's modulus Esm in a range of 1 MPa to 150 MPa, and the material has a nonlinear elastic deformation characteristic;
- producing a protective panel having the soft material layer with a minimum thickness Tsm calculated based on the predetermined value R, mechanical properties of the soft material layer and other materials in the same protective panel;
- and
- wrapping a fabric sheet around the soft material layer, wherein the fabric sheet has a tensile strength of more than 500 MPa and a fracture strain of more than 5%,
- wherein the step of producing the protective panel having the soft material layer with the minimum thickness Tsm comprises:
- calculating Tsm using Equation 4:
- W
- =
- E
- fb
-
- A
- fb
-
- ε
- limit
- 4
- 4
-
- L
- 3
-
- T
- sm
- 4
- +
- 8
- 15
-
- R
-
- E
- sm
-
- ε
- pl
- 5
- /
- 2
-
- T
- sm
- 5
- /
- 2
- +
- 1
- 2
-
- π
-
- R
-
- σ
- pl
- (
- ε
- limit
- 2
- -
- ε
- pl
- 2
- )
-
- T
- sm
- 2
- wherein W is kinetic energy of a pellet of hail having a radius of the predetermined value R, Efb is a Young's modulus of the fabric sheet, Afb is a cross-sectional area of the fabric sheet, Esm is the Young's modulus of the soft material layer, 2L is a length of the soft material layer, σpl is the plateau strength of the soft material layer, εpl is the plateau strain of the soft material layer, εlimit is the compressive strain limit of the soft material layer, and εlimit has a value of 0.5 to 0.6.
Dependencies are inferred from the claim text.