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Luís F. Silva 1 | Eurico Seabra 1 | Mário Lima 1 | Rosa Vasconcelos 2 Janete Alves 3 | Catarina Guise 3 | Daniel

International Conference on Engineering Education ICEE-2010 July 18–22, 2010, Gliwice, Poland. A Successful Partnership for the Development of a Laboratory Friction Testing Apparatus: A Project Review. Dynamics of Mechanical Systems.

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Luís F. Silva 1 | Eurico Seabra 1 | Mário Lima 1 | Rosa Vasconcelos 2 Janete Alves 3 | Catarina Guise 3 | Daniel

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  1. International Conference on Engineering Education ICEE-2010 July 18–22, 2010, Gliwice, Poland A Successful Partnership for the Development of a Laboratory Friction Testing Apparatus: A Project Review Dynamics of Mechanical Systems Luís F. Silva1 | Eurico Seabra1| Mário Lima1 | Rosa Vasconcelos2 Janete Alves3 | Catarina Guise3 | Daniel Martins4 1 Department of Mechanical Engineering University of Minho (Centre for Mechanical and Materials Technologies, CT2M) School of Engineering 2 Department of Textile Engineering Campus de Azurém (Centre for Textile Science and Technology, 2C2T) 4800-058 Guimarães 3 Master student of Biomedical Engineering Portugal 4 Master student of Mechanical Engineering

  2. About us… Where are we? Guimarães European Capital of Culture FRICTORQ project The University of Minho in Guimarães

  3. Summary • Introduction; • The FRICTORQ test rig models (I, II and III): • Design and development of an add-on kit function to measure fabric friction in a liquid environment (FRICTORQ III); • Ongoing research projects: • Objective and subjective touch evaluation of hospital clothing for surgical gowns; • Objective and subjective touch evaluation of Hospital and surgical covers. • Skills acquired; • Concluding remarks.

  4. Introduction • The problem • Fabric handle: • The very common practice of rubbing a fabric between the fingers in order to access its quality and comfort characteristics (a subjective measurement). • Fabric Coefficient of Friction: • A valuable indication of its surface properties; • When touched by hand or other parts of the human body.

  5. Introduction • Our solution • FRICTORQ • Is a novel laboratory equipment based on a new method of accessing fabrics (and other 2D structures) Coefficient of Friction, using a rotary principle and, therefore, measuring Torque: • Simple and giving consistent results; • Only one measurement per sample is needed; • Operator independence.

  6. The FRICTORQ test rig models • FRICTORQ I • Dry clutch: a ring shaped body rubbing against a flat surface; • There are two bodies: the upper one with a contact surface of an annular geometry, which is placed over a horizontal flat lower sample; • The second one is forced to rotate around a vertical axis at a constant angular velocity. Friction coefficient is then proportional to the level of torque being measured by means of a high precision torque sensor; • Two working principles: • Fabric-to-fabric and Steel-to-fabric. Detail of friction area Fabric-to-fabric

  7. The FRICTORQ test rig models • FRICTORQ I Detail of friction area Steel-to-fabric Smooth Metallic Body (SMB) (Ø 50/40), 3,5 kPa Textured Metallic Body (TMB) (Ø 50/40), 3,5 kPa

  8. The FRICTORQ test rig models • FRICTORQ I • Graphical output Fabric-to-fabric Steel-to-fabric (TMB)

  9. The FRICTORQ test rig models • FRICTORQ II • The upper body is now a specially designed contact element, restricted to 3 small pads with an approximately square shape (covered by a number of calibrated steel needles), placed over the fabric sample. This upper body is forced to rotate around a vertical axis at a constant angular velocity. Friction coefficient is again proportional to the torque measured with a precision torque sensor: Being, by definition, Fa=µ.N and N=P/3, where P is the vertical load, the coefficient of friction is expressed by:

  10. The FRICTORQ test rig models • FRICTORQ II The new upper body with 3 small pads: NB - 3,5 kPa Textile Physics Laboratory (Department of Textile Engineering, University of Minho)

  11. The FRICTORQ test rig models • FRICTORQ III • Design and development of an add-on kit function to measure fabric friction in a liquid environment • Design of a new: • Container for the liquid testing; • Upper contact body (maintaining the contact pressure of 3,5 kPa), and • Pressure and centring rings. Final adopted FRICTORQ III model (virtual 3D model)

  12. The FRICTORQ test rig models • FRICTORQ III The manufacture… A typical result obtained with a swimwear fabric: The new FRICTORQ III tester: The produced add-on function:

  13. Ongoing research projects • Objective and subjective touch evaluation of hospital clothing for surgical gowns • The aim is to study and characterize the sensory comfort and touch, as well as the requirements of the fabrics used in hospital garments, specifically in surgical gowns. • Two types of non-wovens were used: • SMS (Spunbond-Melblown-Spunbond), consisting of 100% of polypropylene, and • Suprel (S), made of 80% of polyethylene and 20% of polyester. SMS S

  14. Ongoing research projects Box-plot with the obtained results: • The friction coefficient of SMS, on both sides (IF and OF), is higher than the Suprel non-woven. • The mean values vary between 0,139 and 0,190, with the minimum value obtained for the S_OF sample and the maximum for the SMS_IF. (inner face, IF, and outer face, OF) FRICTORQ with SMS samples (left) and Suprel (right)

  15. Ongoing research projects Scheffe analysis This analysis resulted in four different subsets. Mean difference significance of the ANOVA comparison It was determined that, statistically, all samples presented a different behaviour. Conclusions: From all the collected results it was possible to confirm that the non-woven more rough to the touch (usually evaluated by sliding the fabric between the fingers) has a higher coefficient of friction. Between the two tested non-wovens, SMS is rougher than the Suprel, which confirms the previous plotted results.

  16. Ongoing research projects • Objective and subjective touch evaluation of hospital and surgical covers • This research aimed at the evaluation of the parameters related with the touch of fabrics used in surgical covers and blankets. • Different phases of the project includes the: • Acquaintance with the materials used in this field; • Identification of the most relevant properties needed for the design of a surgical cover; • Understanding of the importance of touch in the evaluation of the materials used in this study; • Preparation of questionnaires to enable a preliminary subjective evaluation of touch; • Comparison of the different materials used, and • Correlation with the objective and subjective parameters of touch.

  17. Ongoing research projects • For this study, FRICTORQ was one of the used instruments and five different materials were tested: • Spunlace (FCP), made up of 55% cellulose and 45% polyester; • VPE (viscose 48,3%, polyethylene 48,3% and 3,4% of hotmelt glue) and PEPP (polyethylene 38,9%, polypropylene 57,8% and 3,3% of hotmelt glue), and • SMS and Suprel as before. FCP VPE PEPP SMS S

  18. Ongoing research projects The obtained results are plotted as follows: • Suprel is the material that exhibits a lower friction coefficient and the OF of VPE exhibits the higher coefficient of friction. • FCP, SMS and PEPP show, nevertheless, similar friction behaviour in both faces. (inner face, IF, and outer face, OF) Final remarks: Although the correlation of the objective with the subjective parameters of touch for all these fabrics is not yet attained, the study and evaluation of the touch of materials used as protective barriers is of great importance, regarding the assessment of the comfort provided by their use as surgical clothing and covers.

  19. Skills acquired The skills acquired by these students can be summarized as follows: KES instruments and tests, FRICTORQ and the thermal instrument ALAMBETA VŠST ÚZCHV • Tools, techniques, procedures and laboratory protocols … friction, surface roughness, absortivity and thermal properties, sample thickness and other mechanical properties • Participation in R&D projects • Characterization of textile materials properties Activities of research and resources management • Background knowledge acquired during undergraduate courses • Knowledge of engineering design methods • Students autonomy Statistical tools for data processing and analysis (regarding the software SPSS® Statistics V.18.0), CAD and Fluent™ software

  20. Concluding remarks • The design and development of a laboratory testing apparatus for measuring the friction coefficient in textiles and other 2D soft structures, named FRICTORQ, was reviewed; • The research framework of three MSc students have also been reported: • Design and development of an add-on kit function to measure fabric friction in a liquid environment; • Objective and subjective touch evaluation of hospital clothing for surgical gowns, and • Objective and subjective touch evaluation of hospital and surgical covers.

  21. Concluding remarks • The integration of knowledge, skills and performance relating to Competency-Based Education in the field of Mechanical Engineering Design and Characterization of new Materials and Products, to be in contact with liquid environments and for hospital applications, was implemented. • The role of the supervisors along this process was just to coach and support students in practice, allowing them the ability to perform particular scientific activities without any direct supervision.

  22. Concluding remarks • All these efforts represent a further step to accomplish the final overall objective: • “the development of a friction testing apparatus to enable a quantitative assessment of the touch/handle, in order to predict the comfort behaviour of 2D/3D structures when used or touched by humans”.

  23. The Textile Physics Laboratory(Department of Textile Engineering, University of Minho)

  24. International Conference on Engineering Education ICEE-2010 July 18–22, 2010, Gliwice, Poland THANK YOU Dynamics of Mechanical Systems A Successful Partnership for the Development of a Laboratory Friction Testing Apparatus: A Project Review • mlima@dem.uminho.pt • +351 253 510 220  •  +351 253 516 007

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