Investigation Into the Flexural Strength of a Material for Resin-Reinforced Rapid Prototyping Transtibial Sockets

Author(s):  
L. H. Hsu ◽  
C. T. Lu ◽  
G. F. Huang ◽  
J. T. Chen ◽  
H. S. Yang ◽  
...  

This investigation employed Taguchi experimental design method and ASTM three-point bending test to determine the parameters that influence the flexural strength of a material composed of a thin layer fabricated by a rapid prototyping (RP) machine and coated with a layer of unsaturated polyester resin (UPR). Since current rapid prototyping machines use a layer-based process to manufacture products, this will result in RP products liable to break along forming layers when bending load is applied. A type of resin-reinforced RP transtibial socket is proposed to strengthen the flexural strength so that the abrupt collapse can be prevented if a transtibial prosthetic socket made by an RP machine. This study proposed wrapping a layer of unsaturated polyester resin around a preliminary thin RP socket manufactured by a fused deposition modeling (FDM) machine to reinforce its flexural strength. Factors affecting the strength of the resin-reinforced RP socket include thickness and forming orientation of the preliminary RP socket, thickness of the UPR layer, and type of material used to make the preliminary RP socket. Employing Taguchi experimental design method and ASTM three-point bending test standard, the parameters that influence the flexural strength of the resin-reinforced RP prosthetic socket can be determined. Based on the appropriate parameters, including thickness of the RP layer and UPR layer, the RP material and RP fabricating orientation, the preliminary thin RP prosthetic sockets can be fabricated by an FDM machine. And the thin layer preliminary RP sockets were then wrapped with cotton socks and laminated UPR layer to form resin-reinforced RP sockets. To confirm the effectiveness of the resin-reinforced sockets developed in this study, a volunteer subject with unilateral left below-knee amputation is recruited to implement the experiment. The pressures at residual limb/socket interface were measured by using a pressure distribution measurement system and movement was captured by a motion analysis system while a volunteer patient wears the resin-reinforced RP socket. The experimental results demonstrated that the applicability of the proposed type of material and a resin-reinforced RP transtibial socket has been verified. A prosthetist may use the interface pressures exerting on stump and gait pattern during walking to assess the suitability of this type of RP socket based on clinical expertise. Further trial use and more subjects are needed to validate the durability of the proposed RP socket.

Author(s):  
L. H. Hsu ◽  
C. T. Lu ◽  
G. F. Huang ◽  
J. T. Chen ◽  
W. C. Chuang ◽  
...  

This article introduced a type of rapid prototyping (RP) transtibial socket that is fabricated by a fused deposition modeling (FDM) machine and wrapped with a layer of unsaturated polyester resin (UPR) to enhance its flexural strength. As current rapid prototyping machines use a layer-based process to manufacture products, this will result in RP products liable to break along forming layers once bending moment is applied. To prevent RP prosthetic socket from breakage, this study proposed wrapping a layer of unsaturated polyester resin around a preliminary thin RP socket to reinforce its flexural strength. Factors affecting the strength of the resin-reinforced RP socket include thickness and forming orientation of the preliminary RP socket, thickness of the UPR layer, and type of material used to make the preliminary RP socket. Employing Taguchi experimental design method and ASTM three-point bending test standard, the parameters that influence the flexural strength of the resin-reinforced RP prosthetic socket can be determined. Based on the appropriate parameters, including thickness of the RP layer and UPR layer, the RP material and RP fabricating orientation, the preliminary thin RP prosthetic sockets can be fabricated by an FDM machine. And the thin layer preliminary RP sockets were then wrapped with cotton socks and laminated UPR layer to form resin-reinforced RP sockets. To confirm the effectiveness of the resin-reinforced sockets developed in this study, the pressures at residual limb/socket interface were measured by using a pressure distribution measurement system and movement was captured by a motion analysis system while a patient wears the resin-reinforced RP socket. Two resin-reinforced RP sockets have been fabricated and tested by a volunteer amputee. Analysis of the experimental results would assist a prosthetist to assess the distribution of interface pressures at the pressure-tolerant (PT) and pressure-relief (PR) areas of the residual limb. And, the gait pattern will be used to evaluate the applicability while the resin-reinforced RP socket is worn. Trial uses for durability test of the proposed RP socket are being arranged.


2010 ◽  
Vol 34 (1) ◽  
pp. 37-45 ◽  
Author(s):  
L. H. Hsu ◽  
G. F. Huang ◽  
C. T. Lu ◽  
D. Y. Hong ◽  
S. H. Liu

This article proposes a type of transtibial socket composed of an inner layer fabricated by a rapid prototyping (RP) machine and an outer layer coated with unsaturated polyester resin. This work integrates contemporary technologies including a handheld scanner and CAD systems, to design a thin primary socket shape and then manufactures the socket using a fused deposition-modeling machine. To prevent breakage caused by the layer-based forming process and to reinforce flexural strength, the current research coats the preliminary RP socket with a layer of unsaturated polyester resin. After shaping the proximal brim of the resin-reinforced RP socket to match the specific stump, this study assembles and aligns a shank and a prosthetic foot to form a prosthesis set. After completing a trial safety walk wearing the prosthesis, which is satisfactory to the amputee and a registered prosthetist, this research measures interface pressures between the stump and the resin-reinforced RP socket. Experiment results demonstrate that the resin-reinforced RP socket is applicable for transtibial amputees. In addition to strengthening the FDM socket and producing consistent socket fit, this study also demonstrates a feasible procedure that employs current technologies to design and manufacture transtibial sockets without plaster moulds.


2011 ◽  
Vol 8 (2) ◽  
pp. 551-560
Author(s):  
Baghdad Science Journal

In this study, composite materials were prepared using unsaturated polyester resin as binder with two types of fillers (sawdust and chopped reeds). The molding method is used to prepare sheets of UPE / sawdust composite and UPE / chopped reeds composite. The mechanical properties were studied including flexural strength and Young's modulus for the samples at normal conditions (N.C). The Commercial wood, UPE and its composite samples were immersed in water for about 30 days to find the weight gain (Mt%) of water for the samples, also to find the effect of water on their flexural strength and Young's modulus. The results showed that the samples of UPE / chopped reeds composite gained highest values of flexural strength (24.5 MPa) and Young's modulus (5.1 GPa) as compared with other composites at (N.C). The results showed that the wet samples of sawdust composite have lowest values of weight gain (Mt %) of water (0.043%) as compared with other composites after immersion. Also it’s showed a slight decrease in values of Young's modulus for all the samples after immersion as compared with the samples at (N.C). Finally it’s showed a slight decrease in values of flexural strength for all the samples except for the composite material formed from UPE / chopped reeds which showed an increase in the value of flexural strength after immersion, where the wet samples of UPE / chopped reeds composite gained (29 MPa) as compared with the samples at (N.C).


Author(s):  
Hyon Wook Ji ◽  
Dan Daehyun Koo ◽  
Jeong-Hee Kang

Cured-in-place pipe (CIPP), as a kind of trenchless sewer rehabilitation technology, is a method to repair sewer pipe using unsaturated polyester resin. This study develops a CIPP liner using hot water or steam curing as well as glass fiber, in contrast to traditional methods, which use nonwoven fabric. Composite material samples were fabricated by combining liner materials using various methods, and the structural characteristics of the liners were compared and analyzed through short- and long-term flexural strength tests. A long-term test was conducted for 10,000 h, and the results revealed 13.3 times higher flexural strength and 8 times higher flexural modulus than the American Society for Testing Materials minimum criteria for CIPP short-term properties. The maximum creep retention factor was 0.64, thereby reducing the design thickness of the CIPP by up to 54%. The structural characteristics also improved when glass fibers were mixed with traditional CIPP liner, making it possible to reduce the thickness by 30%. Glass fibers result in high structural strength when combined with unsaturated polyester resin. Structural strength increased, even when glass fibers were mixed with traditional CIPP liner. The main contribution of this research is the development of a high strength CIPP liner and improvement of the structural properties of CIPP lining without using the specially formulated resin or lining materials.


2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Zekeriya Parlak ◽  
Tahsin Engin ◽  
İsmail Şahin

Magnetorheological (MR) dampers have attracted the interest of suspension designers and researchers because of their variable damping feature, mechanical simplicity, robustness, low power consumption and fast response. This study deals with the optimal configuration of an MR damper using the Taguchi experimental design approach. The optimal solutions of the MR damper are evaluated for the maximum dynamic range and the maximum damper force separately. The MR dampers are constrained in a cylindrical container defined by radius and height. The optimal damper configurations obtained from this study are fabricated and tested for verification. The verification tests show that the dampers provide the specified damper force and dynamic range.


2007 ◽  
Vol 14 (04) ◽  
pp. 817-820
Author(s):  
MIN HUANG ◽  
KE-ZHI LI ◽  
HE-JUN LI ◽  
QIAN-GANG FU ◽  
GUO-DONG SUN

SiC coating for carbon/carbon composites was prepared by pack cementation method. The effects of coating process on the microstructure and the mechanical properties of C / C composites were analyzed by SEM and three-point bending test, respectively. As the infiltrated Si improved the interfaces bonding during the coating process, the flexural strength and flexural modulus of SiC -coated carbon/carbon composites were both increased by about 10% than the naked C / C composites. In addition, the mechanism of the change of failure mode of SiC coated C / C composites and naked C / C composites was addressed.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Francisco Carrión ◽  
Laura Montalbán ◽  
Julia I. Real ◽  
Teresa Real

Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.


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