Preparation and hemisphere forming properties of electric heating fabrics based on tailored fiber placement technology
Objective Electric heating fabrics have a wide range of uses,where deformation is inevitable.Therefore,electric heating fabrics should have the ability to conform to three-dimensional surfaces.The research objective is to design the arrangement of electric heating elements based on temperature matching,construct a multi-element combination electric heating fabric structure,and provide a design basis for compromising optimization of electric heating fabrics for use in special-shaped composite components.Method Using the tailored fiber placement(TFP)technology,aramid bundled nickel chromium alloy wire are fixed onto fiberglass fabric(G1)along a predetermined path to prepare electric heating fabric.The surface density of nickel chromium wire is kept constant,and four kinds of arrangement and distribution are designed,namely linear(E1),sine wave(E2),gear(E3),and cuspate(E4).The electrothermal properties of electric heating fabric under external voltage and its adaptability to hemispherical punch were systematically studied.Results Under a 10 V direct-current voltage,the electric heating fabric rapidly heated up and reached the highest equilibrium temperature on the surface after 30 s.At this point,the power was cut off and the surface of the electrically heated fabric were left for natural cooling.After 30 s of electrification,the maximum equilibrium temperature on the surface of E1 was 159.5℃,while E2,E3,and E4 were 92.8℃,66.7℃,and 31.5℃,respectively.When the formation reached the same displacement,the load on E1,E2,E3,and E4 subjected to the hemispherical punch was significantly greater than that on G1,and the mechanical response was found to be related to the distribution of nickel chromium alloy wire.The maximum formation reaction force of E4 was 72.17 N,which is 75.08%,56.18%,47.23%,and 12.54%higher than that of G1,E1,E2,and E3,respectively.The maximum in-plane shear angles on the surface of G1,E1,E2,E3,and E4 specimens were 34.18°,32.26°,30.8°,28.04°,and 21.08°,respectively.The maximum in-plane shear angle of four types of electric heating fabrics was negatively correlated with the reaction force borne by the hemispherical formation process.The smaller the maximum in-plane shear angle,the greater the reaction force borne during the hemisphere forming,and the more obvious the surface wrinkles of the fabric,the less likely it is to deform.This is because in the hemisphere forming experiment,the formation force in the electric heating fabric can be released through in-plane shear deformation.When the forming displacement was 50 mm along the 45° direction of the fabric,the maximum shear angle occurred at a distance of approximately 79 mm from the apex of the hemisphere.The weft and warp indentation of E1 were 15.8 mm and 16.7 mm,respectively.The weft and warp indentation of the four types of electric heating fabric specimens demonstrated a gradually decreasing trend.This is because the nickel chromium alloy wires with different arrangement and distribution changed the original formation performance of G1 during the forming process,thereby determining the weft and warp indentation of the four types of electric heating fabrics.Conclusion The research revealed that the main factor affecting the maximum equilibrium temperature change on the surface of electric heating fabrics is the arrangement and distribution of nickel chromium alloy wires.The binding friction between the introduced nickel chromium alloy wire and aramid wire changes the stress situation of the overall electric heating fabric during hemisphere forming.The maximum in-plane shear angle of E1,E2,E3,and E4 specimens is negatively correlated with the hemisphere forming reaction force.That is,the greater the reaction force on the electric heating fabric during hemisphere forming,the less likely it is to deform.After the forming test,the appearance of the fabric shows an increase in wrinkles,an increase in defects,and a decrease in the weft and warp indentation.
electric heating fabrictailored fiber placement technologyelectrothermal propertyhemisphere formingin-plane shearing
万方数据
维普
