Introducción

Currently, there are companies in charge of mechanical crushing through a semiautomatic physical process of end-of-life tires (NFU), by using machinery that cuts, grinds, sifts, separates and delivers products of different dimensions. As a technified environmental manager that receives, collects and recycles used tires, contributing to the reduction of the negative environmental impact of these wastes, transforming them into alternative products, promoting the culture of recycling and improving the living standards of all those involved in the production chain, However, due to the lack of information and technical specifications of the material resulting from this recycling, the limitations of the material resulting from recycling and its possible application, particularly nylon, are unknown.
In the country there is an average import demand of light and commercial vehicles of 53,654 units and therefore for the possible application in the manufacture of the internal door panel of which 29,554 units are imported per year from the OMNIBUS BB assembler for cars and trucks , according to the association of automotive companies of Ecuador; which allows this application to be feasible since currently the components of the tires have a mixing percentage of 20% between rubber - nylon - steel for each one of the 200,000 tires processed per year.
This research aims to characterize the Nylon resulting from the tire recycling process from the descriptive method, the properties obtained in the characterization process will define the application of the automotive auto part and its validation by CAD software, CAE, providing a correct application of this new composite material as an alternative for the manufacture of auto parts in the country.

Objetivos

Mechanical and thermal characterization of a recycled material as an alternative for the manufacture of auto parts, using recycled tire materials, validating the mechanical behavior through experimental tests and CAE simulation.
Mechanical and thermal characterization of the Nylon resulting from the tire recycling process using ASTM D3039, ASTM D7624 and ISO 8302 standards for the molding of an interior door panel.

SPECIFIC:
Determine the composition of recycled Nylon and obtain specimens for tensile, flexural and thermal conductivity tests by means of the manual stratification method and compression molding according to the ASTM D3039, ASTM D7624 and ISO 8302 standards respectively.
Perform the mechanical and thermal simulation in SolidWorks of an interior door panel by assigning the properties of the original material and the characterized recycled Nylon.
Carry out the analysis and discussion of the results in order to identify the application properties in the interior door panel.

Método

The research will focus on the characterization of recycled Nylon from tires, through exploratory research taking as a reference previous studies carried out and descriptive research establishing the variables for which the resin specimens with Nylon reinforcement must be made and the subsequent obtaining of properties. mechanical, thermal conductivity which will allow to verify the results for its later application by means of a quantitative investigation.
Methodology. Under the ASTM D3039 / D3039M-17 standards for tensile tests, and ASTM D7264 / D7264M-15 for bending tests and ISO 8302 thermal conductivity test.
To obtain the specimens, the experimental methodology was applied, which allowed to determine the values and percentages of the variables for the matrix and the reinforcement through the manual stratification method by compression in molds. Validating its mechanical and thermal behavior of the internal panel with CAE tools.

Principales Resultados

The results contained in this report correspond to tensile and flexural mechanical characterization tests according to ASTM D3039 / D3039M-17 and ASTM D7264 / D7264M-15 respectively, carried out on three groups of composite material of polyester resin matrix and reinforcement made of nylon fiber. Showing a significant difference between the specimens with wire type reinforcement whose value is 12.72 MPa, and the highest value of ultimate tensile strength is 22.82 MPa for the configuration of specimens with styrene, but also a value of 19 , 26 MPa average for the configuration of the specimens without the addition of styrene, thus determining that with the value 22.82 MPa it is recommended for its use, identifying that the highest average value of the modulus of elasticity is 4997.86 MPa corresponding to the configuration of the specimens with the addition of styrene.

Tensile test:
When reviewing the values obtained in the results, it is obtained that the highest value of tensile strength of 22.82 MPa is found within the configuration of the specimens with fiber reinforcement type wool and addition with styrene, which comparing with results of Bibliographic reference shows that the tensile strength of abaca fiber is between 430-760 MPa, that of polyester resin is between 40-90 MPa (Majewski & Bledzki, 2013). The indicated tensile strength of bibliographic reference for jute is 40 MPa and 66.01 MPa for sisal whose volumetric fraction are similar. It should be noted that the value obtained in our study is lower than the tests carried out on other materials, but the value obtained is also lower than the 78 N / mm2 tensile strength of Nylon PA6, PA66.
When reviewing the values of the modulus of elasticity of the three configurations, a considerable variation is observed, obtaining a high value of 7896.25 MPa for the configuration whose fiber reinforcement is yarn type, a value of 6104.77 MPa for the configuration whose reinforcement of The fiber is wool type with styrene addition but these values correspond to a single specimen tested in each configuration and for the case study the average value of 4997, MPa corresponding to the configuration whose fiber reinforcement is wool type with styrene addition will be taken. whose value is comparable to the results obtained in composite tests with jute and sisal fiber reinforcements that presented values of 2130 and 4420 MPa respectively (Majewski & Bledzki, 2013). Thus, it is also observed that the value obtained in this study is greater than the value of the modulus of elasticity of Nylon PA6, PA66, which is 2850 N / mm2.

Bending test:
The ultimate flexural strength presented variation in the three configurations studied, among which there was a decrease for the composite material made with wool-type fiber reinforcement without the addition of styrene, whose average value is 27.65 MPa, but this value increased in the configuration of wool type fiber reinforcement and styrene addition, the average of which is 35.82 MPa. It should be noted that the value obtained of 35.82 MPa is lower than the values obtained from polyester composite materials reinforced with jute and sisal fiber, whose values are 77 MPa and 93.80 MPa respectively according to bibliographic references (Majewski & Bledzki, 2013).
The comparison of the ultimate flexural strength as a function of deformation can be observed for the different configurations of recycled Nylon and pure Nylon.
The flexural modulus decreased in the tested samples whose configuration of composite material and wool-type fiber reinforcement without the addition of styrene its average value was 1224.46 MPa, but an increase was observed in the values obtained from the tested specimens whose configuration of the wool type fiber reinforcement with addition of styrene whose average is comprised in 2438.48 MPa.

Thermal conductivity:
The values obtained from the tested samples do not show variation among themselves whose value is comprised in 0.149 W / mK, but they do show a decrease in terms of the thermal conductivity value presented in table 1 of this study for Nylon PA6, PA66 whose value it is at 0.25 W / Km.

Side impact simulation:
As shown in the results, the simulation of side impact to the interior door panel was made for two different materials, to make such comparisons between the original material and the studied material. Comparing the displacements with test results carried out by the FMVSS for commercial brands in Ecuador such as Chevrolet, Toyota, Mazda, among others, their displacement values are between 0.696 and 0.785 m (Fmvss, 1999). The displacement value obtained in our simulation for recycled Nylon is 1.8795 m.
The comparison between each of the stress and strain results is presented below.
As can be seen in figure 90, the stress value for the PS material reaches a maximum value of 36722 MPa and for the recycled Nylon a maximum value of 50648 MPa, verifying in both cases that it exceeds the value of its elastic limit.
The unitary deformation results showed variations indicating that the recycled Nylon achieves less deformation than the PS material. As detailed in the simulation method, the thermal test was carried out for the PS material and the recycled Nylon at a temperature of 100 C, obtaining minimum and maximum values.

Conclusiones

The volumetric fraction required to make the nylon-resin composite material specimens, taking into account the ease of construction of the specimens and processing, was 0.37 for both the nylon wool and yarn type specimens.
Ultimate tensile strength decreased relative to ultimate flexural strength for the three characterized configurations as did the ultimate strain. But it had a significant increase in the modulus of elasticity for the wool and yarn type Nylon fiber reinforced composite material.
The selection of the interior door panel to be analyzed with the results of the material characterized by simulation does not comply with the mechanical requirements of resistance and displacement established in the vehicle safety regulations.