• 대한기계학회논문집A
• /
• 제20권6호
• /
• pp.1836-1842
• /
• 1996

In this paper, static and fatigue bending strengths of CFRP(carbon fiber reinforced plastic laminates having impact damage(FOD) are evaluated. Composite laminates used for this experiment are CF/EPOXY and CF/PEEK orthotropy laminated plates, which have two-interfaces[${0^0}_4{90^0}_4}$]$_sym$. A steel ball launched by the air gun colides against CFRP laminates to generate impact damages. The damage growth during bending fatigue test is observed by the scanning acoustic microscope(SAM). When the impacted side is compressed, the residual fatigue bending strength of CF/PEEK specimen P is greater that that of CF/EPOXY SPECIMEN B. On the other hand, when the impacted side is in tension, the residual fatigue bending strength of CF/PEEK speicemen P is smaller than that of CF/EPOXY specimen B. In the case of impacted-side compression, fracture is proposed from the transverse crack generated near impact point. On the other hand, fracture is developed toward the impact point from the edge of interface-b delamination in the case of impacted-side tension.

• 한국전산구조공학회논문집
• /
• 제31권1호
• /
• pp.23-29
• /
• 2018

무릎 임플란트에서 접촉압력이 마모에 큰 영향을 미친다. 본 연구에서는 본 연구기관에서 개발한 무릎 임플란트 모델을 이용하여 유한요소해석을 하였다. 연구와 산업에서 실제로 사용하는 조합을 이용하여 총 10가지의 무릎 임플란트의 재료조합에 대한 접촉압력을 분석하였다. 무릎이 30도, 45도 60도 기울어져있을 때의 하중을 가하여 접촉압력을 구하였다. 접촉압력을 계산한 결과 티타늄합금-UHMWPE 조합에서 가장 작은 접촉압력이 나왔다. UHMWPE의 경우 대퇴골부에 어떠한 재료를 사용하여도 접촉압력이 크게 변하지 않았다. 접촉압력이 가장 큰 조합과 작은 조합을 비교하였을 때 0.77% 차이를 보였다. 반면에 Carbon/PEEK 복합재료의 경우 접촉압력이 가장 큰 경우와 작은 경우를 비교하였을 때 5.3% 차이를 보였다. 이를 통해 Carbon/PEEK 복합재료를 베어링부로 사용할 경우 대퇴골부의 재료가 마모에 영향을 미침을 알 수 있다. 본 연구는 무릎 임플란트 마모예측과 마모를 최소화 연구에 도움이 될 것이라 생각한다.

• Composites Research
• /
• 제29권5호
• /
• pp.243-248
• /
• 2016

열경화성 탄소 섬유 복합재료 분리판은 높은 기계적 특성뿐만 아니라 높은 내산성을 갖으나, 높은 제조단가 및 낮은 자체저항이 극복해야 할 가장 큰 장애물이다. 따라서 본 연구에서는, 열가소성 폴리머를 복합재료 분리판의 기지로 적용하여 분리판 생산성과 자체저항이 모두 증가된 열가소성 탄소 복합재료 분리판을 개발하였다. 전기 전도도 및 기계 강도를 증가시기키 위하여 평직 형태의 탄소 섬유 직물을 사용하였으며, 분리판의 자체 저항을 감소시키기 위하여 전도성 나노입자를 열가소성 기지에 혼합하였다. 개발된 분리판의 면적 비저항 및 기계물성을 고온 연료전지 작동 온도 및 스택의 체결압에 따라 측정하였다.

• Advances in Automotive Engineering
• /
• 제1권1호
• /
• pp.41-59
• /
• 2018

In the study, investigation of fiber- reinforced composite materials that can be an alternative to conventional steel was performed by finite element analysis with the help of software. Steel and composite materials have been studied on a four axle truck chassis model. Three-dimensional finite element model was created with software, and then analyzes were performed. The analyses were performed for static and dynamic/fatigue cases. Fatigue cases are formed with the help of design spectra model and fatigue analyses were performed as static analyses with this design spectra. First, analyses were performed for steel and after that optimization analyses were made for the AS4-PEEK carbon fiber composite and Eglass-Epoxy fiber composite materials. Optimization of composite material analyzes include determining the total laminate thickness, thickness of each ply, orientation of each ply and ply stacking sequence. Analyzes were made according to macro mechanical properties of composite, micromechanics case has not been considered. Improvements in weight reduction up to %50 provided at the end of the composite optimization analyzes with satisfying stiffness performance of chassis. Fatigue strength of the composite structure depends on various factors such as, fiber orientation, ply thickness, ply stack sequence, fiber ductility, ductility of the matrix, loading angle. Therefore, the accuracy of theoretical calculations and analyzes should be correlated by testing.

• 한국자동차공학회논문집
• /
• 제4권4호
• /
• pp.147-155
• /
• 1996

The purpose of present paper is to estimate the static and fatigue bending strengths of CFRP(carbon fiber reinforced plastic) laminates having impact damage(FOD). The specimens which are formed with the different stacking composition, EPOXY and PEEK matirx and orthotropic and quasi-isotropic laminated plates, are prepared for this experiment. A steel ball is impacted on CFRP laminates, generating impact damages, and the three-point fatigue bending test is carried out by using the impacted laminates to investigate the influence of the stackin composition on the fatigue strength of CFRP laminates.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.899-903
• /
• 2009

Recently, research and development of the linear compressor are being active. The reason is that the one has not only higher efficiency than reciprocating type, but also lower noise. But because the dicharge valve of linear compressor is operated in high pressure and temperature circumstance, it is important to prevent leakeage. In this paper three other plastic reinforced composite materials were used. Those are TPI, PEEK and PEK which were containing other volume and kind of carbon fibers. First, for assessing mechanical properties, we measured the hardness and the heating property of the trst sepecimen by the microvickers hardness tester and the differential scanning calorimeter respectively. Finally, through FALEX tester, we could know the characteristics of the wear proving the results of before-conducted experiments.

• Journal of Korean Neurosurgical Society
• /
• 제41권2호
• /
• pp.105-110
• /
• 2007

Objective : This purpose of this study was to determine the clinical efficiency and applicability, and to analyze the radiologic findings of the anterior cervical approach using two synthetic cages for interbody fusion. Methods : A total of 41 patients with cervical diseases underwent anterior discectomy and interbody fusion with the PEEK $Solis^{TM}$ cage in 21 patients and the carbon composite $Osta-Pek^{TM}$ cage in 20 patients. Outcome assessment was done using Odom's criteria. Radiological assessment was performed with respect to subsidence, bony fusion and lordosis. The mean follow-up period was 13 months. Results : There were 34 [92.9%] successful cases. The average height of the disc space 12 months after surgery compared the height just after surgery was decreased over 3mm in 4 cases, indicating severe subsidence. The use of these synthetic cages have provided the increase in postoperative cervical lordosis. Conclusion : There were no significant differences between the $Solis^{TM}$ and $Osta-Pek^{TM}$ cages on clinical and radiologic outcomes. Both $Solis^{TM}$ and $Osta-Pek^{TM}$ cages showed low subsidences and complications associated with hardware with good clinical outcomes, high fusion rates, restored disc heights, and restored cervical lordosis.