Modeling of Compression Curves of Flexible Polyurethane Foam with Variable Density, Chemical Formulations and Strain Rates
Authors
Abstract:
Flexible Polyurethane (PU) foam samples with different densities and chemical formulations were tested in quasi-static stress-strain compression tests. The compression tests were performed using the Lloyd LR5K Plus instrument at fixed compression strain rate of 0.033 s-1 and samples were compressed up to 70% compression strains. All foam samples were tested in the foam rise direction and their compression test stress results were modeled using a constitutive Polymeric or Phenomenological Foam Model (PFM). In this research, a new constitutive PFM model that consists of mechanical systems such as dashpots and springs was formulated to be used for different strain rate experiments. The experimental compression test results for different strain rates were compared to the PFM model results for all foam samples. Both modeling and experimental results showed pretty good agreement. From curve fitting of the experimental tests with the PFM model; different mechanical materials’ coefficients such as elastic and viscous parameters were computed. These mechanical parameters are indeed important characteristics for viscoelastic materials. This model can be used for constant and variable strain rates and for characterizing biomechanical material applications such as bone tissues, muscle tissues and other cellular materials.
similar resources
Glycols in Polyurethane Foam Formulations with a Starch–Oil Composite
A dry starch–oil composite was blended with each of three glycols; ethylene, polyethylene, and propylene, and then reacted with isocyanate to produce polyurethane foams. The liquid glycols permitted the dry composite to blend well with the other ingredients in the foam formulations. Infrared spectra confirmed the presence of urethane structures in the composite–glycol foams. Polyethylene glycol...
full textWaste Minimization Strategy: Flexible Polyurethane Foam Manufacture
Methylene chloride and CFCs are used as auxiliary blowing agents in the manufacture of flexible polyurethanefoams and are promptly emitted during the manufacturing processes.The concentrationof the auxiliary blowing agent are quite low due to the accepted practice of using large volumes of air to lower the ambient concentration of toxic isocyanates (a key chemical in the urethane reaction seque...
full text5. Exploring Urea Phase Connectivity in Molded Flexible Polyurethane Foam Formulations Using LiBr as a Probe
full text
extraction and acetylation of purified trypsin from bovin pancreas and study of some its physico-chemical properties
آنزیم تریپسین در شرایط قلیایی ناپایدار می باشد .و فعالیت پروتئولیتیکی تریپسین منجربه خود هضمی آن در جایگاههای خاصی می گردد. بنابر این آنزیمی با ناپایداری بالا محسوب میگردد. در سالهای اخیر موفق شدند که با ایجاد تغیرات شیمیایی با اضافه کردن فلزات خاص ، کلسیم و یا عمل استیلاسیون منجر به افزایش پایداری آنزیم تریپسین گردند. مطالعات در حال حاضر نشان می دهد که تریپسین استیله شده فعالیت آنزیمی خود را ...
15 صفحه اولNovel Gelling Catalyst for Non-Emission Flexible Polyurethane Foam
Flexible and semi-rigid polyurethane foams have been widely used in automotive interior parts, residential upholstered furniture and bedding. In these, as well as other end use industries, a reduction of Volatile Organic Compounds (VOCs) emissions from polyurethane foams continues to be an important issue [1, 2]. To address this challenge, reactive amine catalysts, which have an active hydrogen...
full texta comparison of teachers and supervisors, with respect to teacher efficacy and reflection
supervisors play an undeniable role in training teachers, before starting their professional experience by preparing them, at the initial years of their teaching by checking their work within the proper framework, and later on during their teaching by assessing their progress. but surprisingly, exploring their attributes, professional demands, and qualifications has remained a neglected theme i...
15 صفحه اولMy Resources
Journal title
volume 6 issue 1
pages 82- 97
publication date 2014-03-30
By following a journal you will be notified via email when a new issue of this journal is published.
Hosted on Doprax cloud platform doprax.com
copyright © 2015-2023