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Stark NEP, Clark C, Rowson S. Human Head and Helmet Interface Friction Coefficients with Biological Sex and Hair Property Comparisons. Ann Biomed Eng 2023:10.1007/s10439-023-03332-9. [PMID: 37540293 DOI: 10.1007/s10439-023-03332-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 07/24/2023] [Indexed: 08/05/2023]
Abstract
Dummy headforms used for impact testing have changed little over the years, and frictional characteristics are thought not to represent the human head accurately. The frictional interface between the helmet and head is an essential factor affecting impact response. However, few studies have evaluated the coefficient of friction (COF) between the human head and helmet surface. This study's objectives were to quantify the human head's static and dynamic COF and evaluate the effect of biological sex and hair properties. Seventy-four participants slid their heads along a piece of helmet foam backed by a fixed load cell at varying normal force levels. As normal force increased, static and dynamic human head COF decreased following power-law curves. At 80 N, the static COF is 0.32 (95% CI 0.30-0.34), and the dynamic friction coefficient is 0.27 (95% CI 0.26-0.28). Biological sex and hair properties were determined not to affect human head COF. The COFs between the head and helmet surface should be used to develop more biofidelic head impact testing methods, define boundary conditions for computer simulations, and aid decision-making for helmet designs.
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Affiliation(s)
- Nicole E-P Stark
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 120 Kelly Hall, 325 Stanger Street, MC 0298, Blacksburg, VA, 24061, USA.
| | - Charlotte Clark
- Department of Materials Science and Engineering, Virginia Tech, Blacksburg, USA
| | - Steve Rowson
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 120 Kelly Hall, 325 Stanger Street, MC 0298, Blacksburg, VA, 24061, USA
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Heap WE, Keeley CT, Yao EB, Naclerio ND, Hawkes EW. Miniature, Lightweight, High-Force, Capstan Winch for Mobile Robots. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3192758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- William E. Heap
- College of Engineering, University of California, Santa Barbara, CA, USA
| | - Chris T. Keeley
- College of Engineering, University of California, Santa Barbara, CA, USA
| | - Elvy B. Yao
- College of Engineering, University of California, Santa Barbara, CA, USA
| | - Nicholas D. Naclerio
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - Elliot W. Hawkes
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
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McMullen RL, Schiess T, Kulcsar L, Foltis L, Gillece T. Evaluation of the surface properties of hair with acoustic emission analysis. Int J Cosmet Sci 2020; 43:88-101. [PMID: 33140853 PMCID: PMC7984217 DOI: 10.1111/ics.12672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The tactile sensation of hair is an important consumer-perceivable attribute. There are limited instrumental options to measure the haptic properties of hair. In this study, we introduce a novel technique using the acoustic emissions produced when skin comes in contact with dry hair in a stroking motion. METHODS Using a free-field microphone with a frequency response of 8-12,500 Hz, we recorded acoustic emission data of the interaction of skin with hair. Data were captured with Electroacoustics Toolbox software and analysed with Matlab. Acoustic emission profiles were generated allowing us to monitor the acoustic response at distinct frequencies. RESULTS Various experiments were conducted to develop this novel technique as a suitable measure to monitor the surface properties of hair. Increasing the normal force and velocity of the interaction led to an increase in acoustic emissions. We also examined the acoustic profile of hair that underwent chemical treatment. For example, bleached hair produced a much higher magnitude acoustic response than the corresponding virgin hair. On the other hand, hair conditioner systems mitigated the acoustic response. Finally, investigations of textured hair revealed that the three-dimensional structure of the hair fibre assembly and its ability to return to its original state when perturbed produce the most dominant acoustic response for this type of hair. CONCLUSION We introduce a cutting-edge method to reproducibly evaluate the surface properties of hair. Different types of hair geometry produce unique acoustic profiles as do hair types that experience harsh damaging treatments. This is also a very practical and efficient way to evaluate the degree of protection or conditioning of the fibre.
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Affiliation(s)
- R L McMullen
- Ashland Specialty Ingredients, G.P., 1005 US HWY 202/206, Building N, Bridgewater, NJ, USA
| | - T Schiess
- Ashland Specialty Ingredients, G.P., 1005 US HWY 202/206, Building N, Bridgewater, NJ, USA
| | - L Kulcsar
- Ashland Specialty Ingredients, G.P., 1005 US HWY 202/206, Building N, Bridgewater, NJ, USA
| | - L Foltis
- Ashland Specialty Ingredients, G.P., 1005 US HWY 202/206, Building N, Bridgewater, NJ, USA
| | - T Gillece
- Ashland Specialty Ingredients, G.P., 1005 US HWY 202/206, Building N, Bridgewater, NJ, USA
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Zhang G, Zeng X, Su Y, Borras FX, de Rooij MB, Ren T, van der Heide E. Influence of suture size on the frictional performance of surgical suture evaluated by a penetration friction measurement approach. J Mech Behav Biomed Mater 2018; 80:171-179. [PMID: 29427933 DOI: 10.1016/j.jmbbm.2018.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 01/20/2018] [Accepted: 02/02/2018] [Indexed: 11/29/2022]
Abstract
The frictional performances of surgical sutures have been found to play a vital role in their functionality. The purpose of this paper is to understand the frictional performance of multifilament surgical sutures interacting with skin substitute, by means of a penetration friction apparatus (PFA). The influence of the size of the surgical suture was investigated. The relationship between the friction force and normal force was considered, in order to evaluate the friction performance of a surgical suture penetrating a skin substitute. The friction force was measured by PFA. The normal force applied to the surgical suture was estimated based on a Hertzian contact model, a finite element model (FEM), and a uniaxial deformation model (UDM). The results indicated that the penetration friction force increased as the size of the multifilament surgical suture increased. In addition, when the normal force was predicted by UDM, it was found that the ratio between the friction force and normal force decreased as the normal force increased. A comparison of the results suggested that the UDM was appropriate in predicting the frictional behavior of surgical suturing.
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Affiliation(s)
- Gangqiang Zhang
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, 200240, Shanghai, China; University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands
| | - Xiangqiong Zeng
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands; Chinese Academy of Sciences, Shanghai Advanced Research Institute, Lubricating Materials Laboratory, 201210 Shanghai, China
| | - Yibo Su
- Brightlands Materials Center, Urmonderbaan 22 6167 RD Geleen, The Netherlands
| | - F X Borras
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands
| | - Matthijn B de Rooij
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands
| | - Tianhui Ren
- Shanghai Jiao Tong University, School of Chemistry and Chemical Engineering, Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, 200240, Shanghai, China.
| | - Emile van der Heide
- University of Twente, Laboratory for Surface Technology and Tribology, 7500AE Enschede, The Netherlands; TU Delft, Faculty of Civil Engineering and Geosciences, Stevinweg 1, 2628 CN Delft, The Netherlands; Ghent University, Soete Laboratory, Technologiepark Zwijnaarde 903, B-9052 Zwijnaarde, Belgium
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Chance G, Jevtić A, Caleb-Solly P, Dogramadzi S. A Quantitative Analysis of Dressing Dynamics for Robotic Dressing Assistance. Front Robot AI 2017. [DOI: 10.3389/frobt.2017.00013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Gerhardt LC, Mattle N, Schrade GU, Spencer ND, Derler S. Study of skin-fabric interactions of relevance to decubitus: friction and contact-pressure measurements. Skin Res Technol 2008; 14:77-88. [PMID: 18211605 DOI: 10.1111/j.1600-0846.2007.00264.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND/PURPOSE Prolonged pressure as well as friction and shear forces at the skin-textile interface are decisive physical parameters in the development of decubitus. The present article describes the contact phenomena at the skin-textile interface and the development of a purpose-built textile friction analyser (TFA) for the tribological assessment of skin-fabric interactions, in connection with decubitus prevention. METHODS Interface pressure distributions were recorded in the pelvic and femoral regions between supine persons and a foam mattress. Fabrics made of various natural and synthetic yarns were investigated using the TFA. A vertical load of 7.7 kPa was applied to the swatches, simulating high interface pressures at the skin-fabric interface and clinical conditions of bedridden persons. Fabrics were rubbed in reciprocating motions against a validated skin-simulating material to determine static as well as dynamic friction coefficients (COFs). RESULTS Maximum contact pressures ranged from 5.2 to 7.7 kPa (39-58 mmHg) and exceeded the capillary closure pressure (32 mmHg) in all investigated bedding positions. For both COFs, a factor of 2.5 was found between the samples with the lowest and highest values. Our results were in a similar range to COFs found in measurements on human skin in vivo. The results showed that our test method can detect differences of 0.01 in friction coefficients. CONCLUSION TFA measurements allow the objective and reliable study of the tribology of the skin-textile biointerface and will be used to develop medical textiles with improved performance and greater efficacy for decubitus prevention.
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Affiliation(s)
- L-C Gerhardt
- EMPA, Laboratory for Protection and Physiology, Swiss Federal Laboratories for Materials Testing and Research, St Gallen, Switzerland.
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