METHOD FOR MANUFACTURING A SANDWICH STRUCTURE

Abstract

The invention relates to a method for manufacturing a sandwich structure comprising two steel-faced sheets separated by a polymer layer. This method comprises the following steps: - dimensioning the sandwich structure according to a target to be achieved, by carrying out the following sub-tasks: steps: - the target to be achieved is defined in terms of three target values, namely the tensile stiffness tc, expressed in kN / mm, the flexural stiffness bc, expressed in kN / mm and the surface mass mc, expressed in kg / m2; - a tolerance margin for achieving the target values ​​is defined;- The sandwich structure is defined as a function of five variables, namely the thickness ea of ​​the steel sheets, expressed in mm, the thickness ep of the polymer layer, expressed in mm, the intrinsic Young's modulus yp of the polymer layer, the intrinsic density dp of the polymer layer and the volume fraction rp of the polymer layer, expressed as a percentage by volume of the polymer material layer; - the combinations of ea, ep, yp, dp and rp allowing the target values ​​to be achieved within the defined tolerance range are defined; - or a useful range is determined for each variable from the above; - the steel and polymer layers are chosen for which each variable lies within the range defined in the previous step; - and the corresponding sandwich structure is produced.

Description

within the range defined in the previous step; - and the corresponding sandwich structure is produced.

Claims

DEMANDS 1) A method for manufacturing a sandwich structure comprising two steel facings separated by a polymer layer, comprising the steps according to which: - The sandwich structure is dimensioned according to a target to be achieved by following the sub-steps according to which: The target to be achieved is defined by three target values, namely its tensile stiffness Te expressed in kN / mm, its flexural stiffness Bc expressed in kN / mm and its surface mass Mc expressed in kg / m 2 , We define a tolerance for achieving the target values, The sandwich structure is defined by five variables, namely the thickness Ea of the steel facings expressed in mm, the thickness Ep of the polymer layer expressed in mm, the intrinsic Young's modulus Yp of the polymer layer, the intrinsic density dp of the polymer layer and the volumetric rate Rp of the polymer layer expressed as a volumetric percentage of the polymer layer containing material, We identify the combinations Ea, Ep, Yp, dp and Rp that allow us to reach the target values ​​with the defined tolerance, From this, we deduce, for each variable, a domain of operation. - we select the steel and the polymer layer for which each variable lies within the domain defined in the previous step, - we manufacture the corresponding sandwich structure. 2) A manufacturing method according to claim 1 wherein the target to be achieved is a monolithic metallic material other than steel. 3) Manufacturing process according to claim 2 wherein the target to be reached is aluminium. 4) Manufacturing method according to claim 3 wherein the target to be achieved is aluminium of thickness equal to 0.9mm. 5) Manufacturing method according to claim 3 wherein the target to be achieved is aluminium of thickness equal to 0.8mm. 6) A manufacturing process according to any one of the preceding claims wherein the tolerance in achieving the target values ​​is 10%. 7) A manufacturing method according to any one of the preceding claims wherein the step of identifying the combinations Ea, Ep, Yp, dp and Rp enabling the target values ​​to be achieved with the defined tolerance includes a step in which combinations Ea, Ep, Yp, dp and Rp are generated. 8) Manufacturing method according to claim 7 comprising a step of graphical analysis of the combinations Ea, Ep, Yp, dp and Rp generated. 9) Sandwich structure obtainable by the process according to any one of claims 1 to 8 implemented for a 0.9mm aluminium target with Tc=31.5N / mm, Bc=10.2N / mm, Mc=2.43Kg / m2 and a tolerance of 10%, the sandwich structure comprising: - Two steel facings with a thickness Ea of steel between 0.133 and 0.165mm, - a polymer layer sandwiched between the two facings and exhibiting: O A thickness Ep between (-2.5xEa0.713) and (-2.5xEa+0.88), A density dp between 0.9 and 1.4, O A volumetric rate Rp greater than or equal to 0.2 and strictly less than al, A Young's modulus Yp less than 4000 MPa, Let the volumetric rate Rp and the Young's modulus Yp satisfy the inequality: Yp*(0.49*Rp 0.23 R+1 / (Yp*(1-Rp))) > 50 MPa ^sandwich structure according to claim 9 wherein the steel thickness Ea is between 0.141 and 0.158mm and the polymer layer thickness Ep is between (-2.5xEaO,73) and (-2.5xEaO,87). 11) Sandwich structure according to any one of claims 9 to 10 wherein the polymer layer comprises a mixture of a polyamide and a copolymer of ethylene and unsaturated carboxylic acid and / or its derivative. I2) sandwich structure obtainable by the process according to any one of claims 1 to 8 implemented for a 0.8mm aluminum target with Tc=28.0N / mm, Bc=7.2N / mm, Mc=2.16Kg / m 2 and a tolerance of 10%, the sandwich structure comprising: - Two steel facings with a thickness Ea of steel between 0.118 and 0.146mm, - A polymer layer sandwiched between the two facings and featuring: O A thickness Ep between (-2.5xEa+0.632) and (-2.5xEa+0.75), A density dp between 0.9 and 1.4, O A volumetric rate Rp greater than or equal to 0.2 and strictly less than al, A Young's modulus Yp less than 4000 MPa, Let the volumetric rate Rp and the Young's modulus Yp satisfy the inequality: Yp*(0.49*Rp O.23*Rp+1 / (Yp*(1-Rp))) > 50 MPa ^sandwich structure according to claim 12 wherein the steel thickness Ea is between 0.126 and 0.140mm and the polymer layer thickness Ep is between (-2.5xEa+0.646) and (-2.5xEa+0.728). I4) sandwich structure according to any one of claims 12 to 13 wherein the polymer layer comprises a mixture of a polyamide and a copolymer of ethylene and unsaturated carboxylic acid and / or its derivative.