3D 프린터 기반의 여성용 맞춤형 중창 디자인을 위한 모델링 프로세스 제안 - 235-240mm의 20대 여성을 대상으로 -

김정현 ( Kim Jeong-hyeon ),정의철 ( Jung Eui-chul ) 한국디자인트렌드학회 2015 한국디자인포럼 Vol.46 No.-

본 연구의 목적은 3D프린터 기반의 맞춤형 중창 디자인을 위한, 중창 디자인 요소를 정의하고 모델링 프로세스를 제안하는 데에 있다. 연구의 목적을 달성하기 위해 맞춤형 중창 디자인 시 필요한 발 치수 요소를 선정하였고 최적화 사이즈를 도출하여 모델링 하였다. 또한 3D프린터로 출력하여 착화감 테스트를 진행하였다. 중창 디자인에 필요한 발 치수 요소로는 발길이와 발너비, 발아치(Arch)이다. 최적화 사이즈는 사용자의 발길이, 발너비를 바탕으로 길이를 가감하여 도출 하였다. 발길이를 기준으로는 발의 양끝에 간격을 주었고, 발너비에 대해서는 감산하여 모델링 하였다. 착화감을 높이기 위해 발모양에 대한 고려가 중요하여, 발의 내·외측면을 사진으로 찍어 발아치(Arch)모양을 모델링 프로세스에 반영하였다. 제안한 프로세스의 타당성 평가를 위하여, 3D프린터로 중창을 출력 하고 피험자들에게 착용하게 하여 사용성 평가를 진행하였다. 피험자는 한국 여성 표준 발 크기인 235~240mm를 착용하는 20대 여성 3명을 단순 무작위 추출을 통해 정하였으며, 제작한 중창에 올라서게 하여 최대 족저압력과 평균 족저압력을 측정하였다. 왼발을 기준으로 측정한 결과, 최대 족저압력의 최대치는 후족부에서 발생하였으며, 후족부 압력의 최대치가 실험자가 평소에 사용하는 일반 중창과 비교하여 다소 낮게 나타났다. 이는 제안한 모델링 프로세스를 활용하면 맞춤형 중창이 한 곳에 집중된 압력을 분산시켜 최대 족저압력을 감소시킬 수 있다는 것을 의미한다. 본 연구는 향후 맞춤형 신발 제작을 위한 기초 연구로 활용될 수 있을 것이다. This research aimed to propose modeling process development for customized woman midsole design based-on 3D Printing technology. To accomplish the objective, we suggested design factors of customized midsole, and presented the optimized foot size, process of midsole modeling. Also, using 3D printed midsole, we performed fit test. Necessary design factors of customized midsole were foot length, ball width and foot arch. Optimized foot size was derived by adding and subtracting based on foot length, ball width. we gave a spare space from end of foot length and subtracted the 6% on ball width. For increasing the comfort of midsole, we took a picture with inner/outer foot side surface and applied to modeling. In order to evaluate the validity of suggested process, we printed a midsole using 3D printer, and conducted usability test to the subjects. The subjects are three women in their 20s, who are wearing a Korean female average foot size of 235~240mm by using the simple random sampling method. Then, subjects stood on the customized midsole and we measured the peak and average plantar pressure, based on the left foot. As a result, the maximum value of peak pressure found on the heel regions. And the peak pressure of heel regions was slightly lower compared to subject`s normal midsole. This result showed that suggested customized midsole modeling process can reduce the high plantar pressure on the heel regions by redistributing the pressure. This finding can be used as a basis for further research of customized shoes making.

달리기 중 신발 중저의 경도가 인체를 따라 흡수되는 충격에 미치는 영향

이용구,김윤혁,Lee, Yong-Ku,Kim, Yoon-Hyuk 대한의용생체공학회 2010 의공학회지 Vol.31 No.1

During running, the human body experiences repeated impact force between the foot and the ground. The impact force is highly associated with injury of the lower extremity, comfort and running performance. Therefore, shoemakers have developed shoes with various midsole properties to prevent the injury of lower extremity, improve the comfort and enhance the running performance. The purpose of this study is to investigate influence of midsole hardness on shock absorption along the human body during running. Thirty two expert runners consented to participate in the study and ran at a constant speed with three different pairs of shoes with soft, medium and hard midsole respectively. Using accelerometers we measured the shock absorption from shoe heel to cervical vertebral column. In conclusion, at the shoe heel, shock was the greatest with the hard midsole. However because most shock was absorbed between shoe heel and the knee, notable influence of midsole was not detected upper knee. At shoe heel, regardless of midsole hardness, the shock of younger female was the greatest. The authors expect to apply this result for providing a guideline for utilizing proper midsole hardness for manufacturing age and gender-specific shoe.

미드솔의 경도 및 두께가 스포츠화의 굽힘 특성에 미치는 영향

박차철 ( Cha Cheol Park ) 한국고무학회 2006 엘라스토머 및 콤포지트 Vol.41 No.2

폴리우레탄(PU)과 폴리에틸렌비닐아세터이트(EVA) 미드솔이 스포츠화의 굽힘 강성에 미치는 영향을 이해하기 위하여 두께와 경도가 다른 중창으로 스포츠화를 제조하여 중창이 스포츠화의 굽힘특성에 미치는 영향을 고찰하였다. 스포츠화의 굽힘 모멘트는 굽힘 각도 19°에서 나타나기 시작했으며, 이 초기 굽힘각도는 중창의 경도나 두께에 무관한 것으로 나타났다. 중창의 경도 및 두께가 증가함에 따라 스포츠화의 굽힘 모멘트의 값은 현저하게 증가하는 경향을 나타내었다. 발포체 시트나 미드솔 자체만으로 비교하였을 때보다 스포츠화의 굽힘 강성이 미드솔의 두께나 경도 등 신발의 설계에 따라 더욱 크게 영향을 받는 것으로 나타났다. To understand the effect of midsole on the bending stiffness of footwear, bending moment is studied with various hardness and thickness of polyurethane(PU) and poly(ethylene-co-vinylacetate)(EVA) foams which composed in footwear midsole. The initial bending moment of footwear was appeared at 19° on bending angle of footwear, and this bending angle was not depend on thickness and hardness of midsole. The bending moments of footwear were also increased with increase of the hardness and thickness of misole which were composed in footwear. Increased hardness and increased thickness of foam and midsole also cause a greater bending moment of the sports shoe, respectively.

Design of three-dimensional Voronoi strut midsoles driven by plantar pressure distribution

Cheng Huaqin,Liu Bin,Liu Meiying,Cao Wei 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.4

The customized production pattern has brought significant innovation to the design and manufacturing of footwear. To improve the matching degree between the consumer’s feet and deepen the customization of the sole’s personalized function, a three-dimensional (3D) Voronoi strut midsole structural design method driven by plantar pressure distribution is proposed in this paper, which not only realizes the functional requirements but also takes into account the aesthetic of midsoles. In this method, the foot characteristics and pressure information obtained by the foot measuring system are employed as the data-driven basic of the midsole structural design, and a weighted random sampling strategy is introduced for constructing the Voronoi sites. Moreover, a Voronoi clipping algorithm is proposed to make the 3D Voronoi diagram adaptive to the midsole boundary. And then, taking the clipped 3D Voronoi edges as skeleton lines, the smooth and continuous 3D Voronoi strut midsoles are generated by the implicit surface modelling technology and implicit function fusion. All the algorithms are integrated into a digital framework by independent programming. And both the static and dynamic tests show that the 3D Voronoi strut midsole can make the plantar pressure distribution more homogenous and can effectively reduce the load on the metatarsal and heel region. What is more, it can provide superior energy absorption and cushioning properties, offer better resilience, bring consumers a more comfortable wearing experience and reduce the probability of joint injury caused by the abnormal plantar pressure concentration.

Effects of Hardness and Thickness of Polyurethane Foam Midsoles on Bending Properties of the Footwear

Park, Cha-Cheol,Choi, Wo-Sung,Lee, Jong-Nyun The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.2

In sports shoe design to achieve better athletics performance, the bending stiffness of a footwear is an important parameter. Its bending stiffness is mostly dependent on its midsole material. Specifically, hardness and thickness oft he midsole material are the major factors on its bending stiffness. Hence, this study focuses on studying the effect of hardness and thickness on bending stiffness of sports shoes by using polyurethane(PU) foam midsole. The results from the experiments show that the bending moment increases as the bending angle increases. Increased hardness and increased thickness of mid sole also cause a greater bending moment of the sports shoe, respectively. Moreover, the effect of hardness and thickness of midsole on bending moment measured with assembled shoes is much greater than the one measured with midsoles alone. Therefore, low bending stiffness of the midsole material can not be ignored in shoe design because it could result in high bending stiffness of an assembled shoe.

비선형 유한요소법을 이용한 신발 해석 및 설계

문병영 ( Mun Byeong Yeong ),김병수 ( Kim Byeong Su ) 한국고무학회 2003 엘라스토머 및 콤포지트 Vol.38 No.3

본 논문에서는 미드솔에 에어싸이클 펌프를 장착한 골프화에 대한 해석적 방법과 설계 기술을 보여준다. 골프화는 유한요소법으로 모델링 하였으며, 더 나은 설계를 위해서 신발을 구성하는 미드솔과 아웃솔의 형상을 고려하였다. 또한 미드솔에 있는 에어싸이클 펌프의 최적의 크기와 형상을 조사하였다. 표준 인체 압력 값을 유한요소해석의 경계 값으로 채택하였다. 오그덴 타입의 변형률에너지 함수의 미지 상수는 인장시험에 따라서 조사하였다. 비선형해석을 위해서 상용 유한요소해석 프로그램 MARC V7.3을 이용하여 미드솔과 아웃솔의 변형률과 부피 변화 값을 각각 구하였다. 미드솔과 아웃솔 유한요소법에 의해 구해진 값은 탄성체의 특성에 따라서 달리 나타난다. 여기에 보인 결과는 보다 나은 골프화 해석에 사용될 것이다. 더욱이, 결과 값들은 보다 효과적인 방법을 개발하기 위한 방법으로 신발산업체에 사용되어 질 수 있다. This paper presents an analytic method and a design technique for golf shoes with air-cycled pump in the midsole. The golf shoes are modeled using the finite element method for better design by considering the configuration of the misole and the outsole, which compose the golf shoes. Also the optimum size and shape of air-cycled pump in the midsole is examined. The values of standard human pressure for boundary conditions are adopted for the FEA(Finite Element Analysis). The unknown constants of the strain energy function of Ogden type are observed in accordance with the axial tension test. By the commercial FEM software for nonlinear analysis, MARC V7.3, the strains and the values of volume change for the midsole and the outsole are obtained, respectively. It can be concluded that results obtained by FEM in the midsole and the outsole are different depending on the characteristic of elastomer. The results reported herein provide better understanding of analyzing the golf shoes. Moreover, it is believed that those properties of the results can be utilized in the shoes industry to develop the effective design method.

미드솔의 반발탄성이 러닝화의 생체역학적 특성에 미치는 영향

유찬일 ( Chan Il Yoo ),원용관 ( Yong Gwan Won ),김정자 ( Jung Ja Kim ) 한국운동역학회 2015 한국운동역학회지 Vol.25 No.1

Objective : The purpose of this study was to evaluate the effect for running shoes with resilience of midsole on biomechanical properties· Methods : 10 healthy males who had no history of injury in the lower extremity with an average age of 26·5 year(SD=1·84), height of 172·22cm(SD=4·44) and weight of 67·51 kg(SD=6·17) participated in this study· All subjects ran on the treadmill wearing three different running shoes· Footpressure data was collected using Pedar-X system(Novel Gmbh, Germany) operating at 100 Hz· Surface EMG signals for biceps femoris, rectus femoris,vastus lateralis, medial lateralis, tibialis anterior, medial gastrocnemius, soleus and peroneus longus were acquired at 1000 Hz using Bignoli 8System(Delsys Inc·, USA)· To normalize the difference of the magnitude of muscle contractions, it was expressed as a percentage relative to themaximum voluntary contraction (MVC)· The impact resilience of the midsole data was collected using Fastcam SA5 system(Photron Inc·, USA)· Collected data was analyzed using One-way ANOVA in order to investigate the effects of each running shoes· Results : TPU midsole was significantly wider in contact area than EVA, TPE midsole in midfoot and higher in EMG activity than EVA midsole atbiceps femoris· TPE midsole was significantly wider in contact area than EVA midsole in rearfoot and higher in peak pressure than EVA midsole inforefoot· EVA midsole was significantly higher in EMG activity than TPU midsole at tibia anterior· In medial resilience of midsoles, TPE midsole wassignificantly higher than EVA, TPU midsole· Conclusion : TPU midsole can reduce the load on the midfoot effectively and activate tibialis anterior, biceps femoris to give help to running·

달리기 시 하지관절의 에너지 반환 방법(Joint Power Method)을 이용한 마라톤화 Sole의 Optimal Bending Stiffness 산출

곽창수,이충일,양정수,권오복,전민주 대한운동사협회 2010 아시아 운동학 학술지 Vol.12 No.4

[INTRODUCTION] The purposes of this study were to determine optimal bending stiffness of a marathon shoe which increased bending stiffness, rearfoot control and impact force absorption of marathon shoe sole, and to compare usual methodology with energy return method(joint power method) for determining optimal midsole hardness. [METHOD] The subjects employed for this study were 13 college students who did not have lower extremity injuries for the last one year and whose running pattern was rearfoot striker of normal foot. The shoes used in this study had 4 different midsole hardness of shoe A 40, shore A 50, Shore A 60, Shore A 70 and bending stiffness was 0.05 N.m/deg - 0.4 N.m/deg. The lower leg motion during at the speed of 4m/sec were measured using a force platform and motion analysis system. [RESULT] The findings of the study were as follows : 1. It was appeared that total contact time of each phase was decreased as the increment of marathon shoe midsole hardness. 2. Maximal impact force and maximal impact force loading rate increased except shore A 40 as the midsole hardness increased. It was shown that Shore A 40 and Shore A 70 were not fitted for a marathon shoe. 3. Initial achilles tendon angle of each midsole hardness was shown similar results, and a maximal achilles tendon angle and a angular displacement of achilles tendon angle was the largest at shore A 40 and the smallest at shore A 50. 4. Initial rearfoot angle was the smallest at shore A 60 and the largest at shore A 70. A minimum rearfoot angle and the displacement of rearfoot angle was the largest at shore A 50 and the smallest at shore A 60. 5. Maximal power in 1st contact contact phase was not shown any particular tendency, but in 2nd contact phase maximal power was increased as midsole hardness was increased and distal joint. 6. The energy in 1st phase was produced at hip joint and absorbed at knee joint and ankle joint, in 2nd contact phase the energy was largest at knee joint and increased as midsole hardness was increased. [CONCLUSION] The study confirmed the previous findings that the midsole hardness of marathon shoe did influence on impact force absorption, rearfoot stability and joint energy. The optimal midsole hardness of marathon shoe was most fitted at shore A 50 and the next shore A 60 by usual shoe methodology study. It was proved that shore A 40 and shore A 70 were not fitted for marathon shoe sole. Also it was appeared that shore A 50 was the most fitted for marathon shoe sole by new attempted joint power method results that the joint energy was largely generated as midsole hardness was most flexible or hard. However, the study suggests that the similar studies like energy return were performed verified optimal bending stiffness because these conclusions were based only on tendencies of current results. [서론] 본 연구의 목적은 마라톤화 바닥의 Bending Stiffness도 증가되고 후족제어나 충격력 흡수가 잘 되는 최상의 조합(stiffness)을 규명하며, 종래의 연구방법과 Joint Power Method의 적정 신발바닥의 강도를 결정하기 위한 연구방법을 상호 비교하는데 있다. [방법] 본 연구에 동원된 피험자는 최근 1년 이내에 하지에 부상경험이 없는 남자 대학생 13명이었다. 본 연구에 사용된 마라톤화는 Bending Stiffness가 0.05 N.m/deg∼0.4 N.m/deg이며, 중저의 경도가 Shore A 40, Shore A 50, Shore A 60, Shore A 70의 4종류이었다. 달리기 시 하지동작을 3차원 영상분석법과 지면반력 측정을 통하여 분석하였다. [결과] 마라톤화의 경도가 증가함에 따라 구간별 걸린 시간도 감소하는 것으로 나타났고 충격흡수변인과 후족제어변인을 분석한 결과 마라톤화 중저의 경도는 50도가 적합한 것으로 나타났다. 하지관절의 에너지와 파워는 굴곡강도가 클수록 통계적인 차이는 없지만 증가하였으며 원위관절로 갈수록 증가하는 것으로 나타났다. [결론] 기존의 신발평가방법과 에너지 반환법을 비교했을 때 평가방법 성격의 차이에 의하여 적정굴곡강도를 선정하는데 차이를 보였다. 에너지 반환법을 이용한 마라톤화 바닥의 적정굴곡강도는 경도가 클수록 증가하는 경향을 보였지만 통계적인 차이를 나타내지 않아 현재의 연구결과로서 현장에 적용하기 어렵다고 사료된다.

런닝화의 미드솔 경도가 하지 근육의 피로와 충격력에 미치는 영향

( Eonho Kim ),( Kyuchan Lim ),( Seunghyun Cho ),( Kikwang Lee ) 한국운동역학회 2019 한국운동역학회지 Vol.29 No.3

Objective: The aim of this study was to investigate the effect of midsole hardness of running shoe on muscle fatigue and impact force during distance running. Method: Ten healthy college recreational runners who were performing distance running at least three times a week participated in this experiment. They were asked to run for 15 minutes in the treadmill at 10 km/h with running shoes having three different types of midsole hardness (Soft, Medium, Hard). EMG signal and insole pressure were collected during the first and last one minute for each running trials. Data were analyzed using a one-way analysis of variance (ANOVA) with repeated measures. Results: Midsole hardness did not affect the consistency of stride length. For the median frequency of the EMG signal, only VL was affected by midsole hardness; that of medium was greater than other midsoles (p<.05). The loading rate of impact forces increased by midsole hardness (p<.01). Conclusion: Although soft midsole could attenuate impact forces at heel contact, it might have a negative effect on the fatigue of muscle which could decelerate the body after heel contact. Therefore, it is necessary to select the optimum hardness of midsole carefully for both reduction impact forces and muscle fatigue.

런닝화의 미드솔 경도가 하지 근육의 피로와 충격력에 미치는 영향

김언호,임규찬,조승현,이기광 한국운동역학회 2019 한국운동역학회지 Vol.29 No.3

Objective: The aim of this study was to investigate the effect of midsole hardness of running shoe on muscle fatigue and impact force during distance running. Method: Ten healthy college recreational runners who were performing distance running at least three times a week participated in this experiment. They were asked to run for 15 minutes in the treadmill at 10 km/h with running shoes having three different types of midsole hardness (Soft, Medium, Hard). EMG signal and insole pressure were collected during the first and last one minute for each running trials. Data were analyzed using a one-way analysis of variance (ANOVA) with repeated measures. Results: Midsole hardness did not affect the consistency of stride length. For the median frequency of the EMG signal, only VL was affected by midsole hardness; that of medium was greater than other midsoles (p<.05). The loading rate of impact forces increased by midsole hardness (p<.01). Conclusion: Although soft midsole could attenuate impact forces at heel contact, it might have a negative effect on the fatigue of muscle which could decelerate the body after heel contact. Therefore, it is necessary to select the optimum hardness of midsole carefully for both reduction impact forces and muscle fatigue.