Method to design honeycombs for a shear flexible structure
View Patent ↗A design method for optimizing the shear layer of a shear band for use in a tire is provided. The shear layer has a honeycomb configuration and the design method optimizes the dimensions of the honeycomb.
1. A computer implemented method for designing a tire, said tire having a shear band that has a desired in-plane effective shear stiffness, G 12 *, a desired maximum shear strain, (γ 12 *)max, a shear layer, said shear layer having a honeycomb structure having a plurality of vertical members, a summation of lengths of said vertical members, H′, an overall height, H, a plurality of horizontal cells, N h , a wall thickness, t, vertical layers, N v , a length of the honeycomb structure, L, a defined variable, d, which is the ratio of said length, L to the number of said plurality of horizontal cells, N h , another defined variable, R, which is the ratio of said summation of lengths of said vertical members, H′ relative to said overall height, H, in order to obtain said G 12 * and said (γ 12 *)max, the method comprising the following steps:
first, holding constant said wall thickness t and said vertical layers N v in a computer implemented algorithm, and second, using the computer implemented algorithm, temporarily fixing d and determining a value of said variable R that provides said desired (γ 12 *)max.
2. The method of claim 1 , which further comprises the step of holding constant the value of R and finding a value of d that provides the desired value of G 12 *.
3. The method of claim 2 , which further comprises the step of choosing a value for d so that N h as calculated by L/d is an integer so that the honeycomb structure has the desired dimensions.
4. A tire that comprises a shear band with a shear layer designed by the method of claim 1 .
5. A computer implemented method for design of a shear layer for use in a shear band of a tire, said shear layer having a desired in-plane effective shear stiffness, G 12 *, a desired maximum shear strain, (γ 12 *)max, said method including the use of a honeycomb design algorithm, said honeycomb having a plurality of vertical members, a summation of a vertical member lengths H′, an overall height, H, a plurality of horizontal cells, N h , wall thickness, t, vertical layers, N v , a length of the honeycomb structure, L, a defined variable, d, which is the ratio of said length, L, to said number of horizontal cells, N h , another defined variable R, which is the ratio of the summation of said vertical member lengths, H′, relative to said overall height, H, said method comprising the following steps:
first, inputting a one or more constituent material properties, a design value for said height, H, a design value for said length, L, a target range for (γ 12 *)max, and a target value of G 12 * into the computer implemented honeycomb design algorithm, and
second, using the computer implemented algorithm to fix the number of horizontal cells, N h , to an initial value N h1 and using a bisection loop to find a value of R that will produce a value for (γ 12 *)max within a specified range, wherein the value of N h1 used in this step is found using the equation N h1 =2L/H, which sets d to be approximately equal to H/2 while ensuring that N h1 is an integer.
6. The method of claim 5 , which further comprises the step of holding the value of R found in the previous step constant and calculating N hf , wherein N h1 , N h2 and G 12 * have a linear relationship, using the following equation:
N
hf
=
[
N
h
1
+
(
(
G
12
*
)
targ
-
(
G
12
*
)
1
(
G
12
*
)
2
-
(
G
12
*
)
1
)
(
N
h
2
-
N
h
1
)
]
(
10
)
wherein the effective shear stiffness corresponding to N h1 , G 12 *1, is taken from step two and a second data point N h2 , which is needed to use said linear relationship between N h1 , N h2 and G 12 * to find N hf , is calculated by doubling N h1 and finding the corresponding effective shear stiffness, G 12 *2 using step two.
7. The method of claim 6 , wherein once R and N hf are found, changing the initial values for N v and t and repeating step two again for the new combination of N v and t.
8. The method of claim 7 , further comprising reporting the resulting structures for each topology combination along with their effective properties.
9. A tire made with a shear band that has a shear layer designed according to the method of claim 5 .