Study Of The Influence Of Flash Fire To The Deformation Of Flame-resistant Fabric

Thermal deformation occurs when flame-resistant fabric confronts with fire and the degree of it is affected by the performance characteristic of fabric and the complicated environment such as hazards of flame as well as radiant heat.Fabricated into firman cloth and faced complicated surrounding environment,flame-resistant fabric changes tremendously,which causes the severe burn of skin by direct contact with scorching fabric or the exposure of skin because the thermal shrinkage deformation of fabric.The study on shape deformation of fabric under the condition of flash fire is rare.It mainly focuses on smoothness,roughness and pilling of fabric.Two dimension image of fabric can be acquired by using CCD camera in tradition method;Three dimension image can be restored through mathematical algorithm,and then the surface characteristics of fabric can be analyzed.Based on thermal protective performance(TTP)experiment,6 kinds of flame-resistant fabrics were delved which were conducted by transient flash fire for 3 and 4 seconds and acquired visual and accurate three-dimensional point cloud data of fabric surface according to the theory of laser triangulation measurement via handy three-dimensional laser scanner.Through Geomagic software,images were fixed and optimized.Height and slope images were built through using point cloud data and 8 characteristic values were collected by means of ArcGis three-dimensional program and Matlab.Evaluation system of flame-resistant fabric thermal deformation level was built.By using factor analysis,weight coefficient of each characteristic value was analyzed;bulging height of fabric was described through maximum height,average height of bulging and projection volume;fabric wrinkle was described through roughness,average slope,slope density and superficial area rate;the degree of shrink was described through fabirc shrinkage rate.The thermal deformation of the whole fabric was described through bulging height,wrinkle and shrink.And the deformation degree of those six kinds of fabrics under different combust time could be analyzed accurately from the established system.Analyzed the influencing factors of fabric flame thermal deformation.Negative correlation could be found between the deformation and weigh,thickness of fabric,especially the weight.To prevent severe thermal deformation of flame-resistant fabric when it combust to flash fire,weight should be considered to be increased primarily.With the increasing time of combust,the proformanc of thickness could reinforce to decrease deformation.It is also a negative correlation between the thermal protective proformance and the degree of thermal deformation.The more severe the fabric deformation is,the lower the fabric's TPP is.Under the condition of 4 seconds'combust,it is positive correlation between fabric and clothing shrunk rate and the correlation index revealed 0.806,which means clothing shrinkage could be estimated through shrinkage of fabric.The research provided the fundamental data to the study on clothing thermal shrinkage and laid the foundation of clothing material choosing.