title: Creep analysis of silicone for podiatry applications.
abstract: This work shows an effective methodology to characterize the creep-recovery behavior of silicones before their application in podiatry. The aim is to characterize, model and compare the creep-recovery properties of different types of silicone used in podiatry orthotics.
  
  
  
  Creep-recovery phenomena of silicones used in podiatry orthotics is characterized by dynamic mechanical analysis (DMA). Silicones provided by Herbitas are compared by observing their viscoelastic properties by Functional Data Analysis (FDA) and nonlinear regression. The relationship between strain and time is modeled by fixed and mixed effects nonlinear regression to compare easily and intuitively podiatry silicones.
  
  
  
  Functional ANOVA and Kohlrausch-Willians-Watts (KWW) model with fixed and mixed effects allows us to compare different silicones observing the values of fitting parameters and their physical meaning. The differences between silicones are related to the variations of breadth of creep-recovery time distribution and instantaneous deformation-permanent strain. Nevertheless, the mean creep-relaxation time is the same for all the studied silicones. Silicones used in palliative orthoses have higher instantaneous deformation-permanent strain and narrower creep-recovery distribution.
  
  
  
  The proposed methodology based on DMA, FDA and nonlinear regression is an useful tool to characterize and choose the proper silicone for each podiatry application according to their viscoelastic properties.
authors.affiliation: Department of Health Science, Faculty of Nursing and Podiatry, Universidade da Coruña, Spain. Electronic address: julia.janeiro@udc.es.
authors.forename: Julia
authors.initials: J
authors.lastname: Janeiro-Arocas
authors.affiliation: Department of Mathematics, Higher Polytechnic University College, Universidade da Coruña, Spain. Electronic address: jtarrio@udc.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Tarrío-Saavedra
authors.affiliation: Department of Industrial Engineering II, Higher Polytechnic University College, Universidade da Coruña, Spain. Electronic address: jorge.lopez.beceiro@udc.es.
authors.forename: Jorge
authors.initials: J
authors.lastname: López-Beceiro
authors.affiliation: Department of Mathematics, Higher Polytechnic University College, Universidade da Coruña, Spain. Electronic address: salva@udc.es.
authors.forename: Salvador
authors.initials: S
authors.lastname: Naya
authors.affiliation: Department of Industrial Engineering II, Higher Polytechnic University College, Universidade da Coruña, Spain. Electronic address: adrian.lcanosa@udc.es.
authors.forename: Adrián
authors.initials: A
authors.lastname: López-Canosa
authors.affiliation: Department of Industrial Engineering II, Higher Polytechnic University College, Universidade da Coruña, Spain. Electronic address: nicolas.heredia.garcia@udc.es.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Heredia-García
authors.affiliation: Department of Industrial Engineering II, Higher Polytechnic University College, Universidade da Coruña, Spain. Electronic address: rartiaga@udc.es.
authors.forename: Ramón
authors.initials: R
authors.lastname: Artiaga
mesh_terms: D004548:Elasticity; D008422:Materials Testing; D009989:Orthotic Devices; D011032:Podiatry; D012828:Silicones / Q000032:analysis*; D013314:Stress, Mechanical; D014783:Viscosity
chemical_list: D012828:Silicones
keywords: Dynamic Mechanical Analysis; Functional Data Analysis; Orthotics; Podiatry; Silicones; Statistical learning