• Title/Summary/Keyword: Plastic analysis method

Search Result 1,829, Processing Time 0.027 seconds

A study on the Kineticism which was introduced to Boundary form in Interior Design (실내디자인에 있어서 경계의 형태에 도입된 키네티시즘에 관한 연구)

  • Choi, Joo-Yeun;Lee, Jin-Min
    • Archives of design research
    • /
    • v.18 no.3 s.61
    • /
    • pp.171-180
    • /
    • 2005
  • The purpose of this research is to investigate the nature of direction of the design corresponding to a human-centered design, digitalism, ecological design, and culture-oriented design which is an issue of design in the 21st century, from the design of the inside of a room. As a method of approach to this objective, first, 1 understand the form of boundary structure appearing in space, through the theoretical investigation of a boundary form. This research is trying to elicit the expression characteristic of kineticism which was introduced to the boundary form as a factor constituting space, by investigating the characteristic of kinaticism which was expressed in plastic arts and other genres. As a process of the proceeding of this investigation, It is explained the background, purpose, and method of this study in Chapter I, and look into the characteristic of the unfolding and expression of kinetic arts as well as the structure of a boundary form of space in Chapter II. In Chapter III, I divide the aspect of modern architectural space into realistic movement, relative movement, and associational movement and examine them. In Chapter IV, I investigate a case of modern space in which the three types of the characteristic of movement mentioned in Chapter Three was expressed, and analyze to what boundary structure the space was introduced. Last of all, in Chapter V, I elicit the characteristic of a boundary form of kineticism which was the result that appeared through the above analysis, and present the nature of future direction of interior.

  • PDF

Optimum Design of Lock Snap-fit Using Design of Experiment (실험계획법을 이용한 이탈방지 스냅핏의 최적설계)

  • Son, In-Seo;Shin, Dong-Kil
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.18 no.8
    • /
    • pp.378-385
    • /
    • 2017
  • This study investigated the design of a snap fit, which is widely used for fastening plastic parts. We analyzed the assembly mechanism of a lock snapfit, measured the assembly force and separation force based on the design of experiments, and derived a regression equation through an analysis of variance. The response surface methodology was also used. Polybutylene terephthalate was used to fabricate specimens, and the assembly force and separation force were measured using a micro-tensile tester. The length, width, thickness, and interference were considered as factors. A second-order regression model was used to derive the regression equation. The assembly force decreased with increasing length and width, but it increased with increasing thickness and interference. The finite element method was used to analyze the assembly mechanics. The width decreased the assembly force by increasing the ductility. The influences of the factors for low assembly force and high release force were shown to be opposite to each other. It was necessary to design a structure that minimized the assembly force while maintaining an appropriate level of separation force.

Low Cycle Fatigue Life Behavior of GFRP Coated Aluminum Plates According to Layup Number (적층수에 따른 GFRP 피막 Al 평활재의 저주기 피로수명 평가)

  • Myung, Nohjun;Seo, Jihye;Lee, Eunkyun;Choi, Nak-Sam
    • Composites Research
    • /
    • v.31 no.6
    • /
    • pp.332-339
    • /
    • 2018
  • Fiber metal hybrid laminate (FML) can be used as an economic material with superior mechanical properties and light weight than conventional metal by bonding of metal and FRP. However, there are disadvantages that it is difficult to predict fracture behavior because of the large difference in properties depending on the type of fiber and lamination conditions. In this paper, we study the failure behavior of hybrid materials with laminated glass fiber reinforced plastics (GFRP, GEP118, woven type) in Al6061-T6 alloy. The Al alloys were coated with GFRP 1, 3, and 5 layers, and fracture behavior was analyzed by using a static test and a low cycle fatigue test. In the low cycle fatigue test, strain - life analysis and the total strain energy density method were used to analyze and predict the fatigue life. The Al alloy did not have tensile properties strengthening effect due to the GFRP coating. The fatigue hysteresis geometry followed the behavior of the Al alloy, the base material, regardless of the GFRP coating and number of coatings. As a result of the low cycle fatigue test, the fatigue strength was increased by the coating of GFRP, but it did not increase proportionally with the number of GFRP layers.

A Study on Mechanical Properties and Applicability of CNT-Mixed Grout (CNT-Mixed grout의 역학적 특성 및 적용성 연구)

  • Kim, Seunghyun;Kim, Kanghyun;Shin, Jongho
    • Journal of the Korean GEO-environmental Society
    • /
    • v.23 no.9
    • /
    • pp.5-16
    • /
    • 2022
  • In recent years due to the development of urban and underground space, the number of ground disasters is increasing, and it is also leading to social problems. To solve the problem, a grouting method is generally used. However, the grouting method has material (grout) limitations in permeability, gelation properties and tensile resistance. Therefore, research on grout materials mixed with fibers is actively carried out to improve the problems. However, in the actual ground injection process, many difficulties have been faced causing the blockage of the inlet port and the injection tube. In this study, 'CNT-mixed grout material' was developed using CNT powder that can reinforce the tensile strength of soils. The uniaxial compressive and tensile strength tests were performed to obtain the optimal content and mechanical properties of the CNT Powder-mixed grout. It was found that the optimal CNT powder content is 0.5% that gives the average maximum strength. A one-dimensional injection test and the bulb formation test were carried out, and it was identified that the injection rate and bulb form could be controlled by pressure and mixing ratio. Field application of the CNT-Mixed grout is simulated using numerical analysis of slopes, foundations, and tunnels reinforced in several types. The positive effect of reducing plastic ranges and settlements was confirmed.

A Comparative Study on the Effect of Tamping Materials on the Impact Efficiency at Blasting Work (발파작업 시 충전매질에 따른 발파효과 비교 연구)

  • Bae, Sang-Soo;Han, Woo-Jin;Jang, Seung-Yup;Bang, Myung-Seok
    • Journal of the Korean Geosynthetics Society
    • /
    • v.21 no.2
    • /
    • pp.57-65
    • /
    • 2022
  • This study simulated the shock wave propagation through the tamping material between explosives and hole wall at blasting works and verified the effect of tamping materials. The Arbitrary Lagrangian-Eulerian(ALE) method was selected to model the mixture of solid (Lagrangian) and fluid (Eulerian). The time series analysis was carried out during blasting process time. Explosives and tamping materials (air or water) were modeled with finite element mesh and the hole wall was assumed as a rigid body that can determine the propagation velocity and shock force hitting the hole wall from starting point (explosives). The numerical simulation results show that the propagation velocity and shock force in case of water were larger than those in case of air. In addition, the real site at blasting work was modeled and simulated. The rock was treated as elasto-plastic material. The results demonstrate that the instantaneous shock force was larger and the demolished block size was smaller in water than in air. On the contrary, the impact in the back side of explosives hole was smaller in water, because considerable amount of shock energy was used to demolish the rock, but the propagation of compression through solid becomes smaller due to the damping effect by rock demolition. Therefore, It can be proven that the water as the tamping media was more profitable than air.

CLINICAL ANALYSIS OF GONIAL ANGLE CHANGE AFTER ORTHOGNATHIC SUGERY IN PATIENTS WITH THE MANDIBULAR PROGNATHISM (하악전돌증환자의 악교정수술후 하악각변화에 관한 임상적 분석)

  • Kwon, Yeong-Ho;Jang, Hyun-Jung;Lee, Sang-Han
    • Maxillofacial Plastic and Reconstructive Surgery
    • /
    • v.22 no.2
    • /
    • pp.206-216
    • /
    • 2000
  • Predictional study for lateral change between pre- and post-orthognathic surgery has been emphasized mainly on anterior area of lateral profile; upper lip, lower lip and chin et al. So interest for lateral profile change has been less in posterior area of lateral profile and literature analyzing gonial angle change is rare. The purpose of this study is to make prediction for gonial angle change possible and to offer somewhat treatment guidance for gonial angle to be improved by investigating overall gonial angle change between pre- and post-orthognathic surgery and inquiring into factors influencing on pattern of genial angle change. For this study 35 patients were selected retrospectively. Lateral cephalometric radiographs were taken in just pre-op time, pod 1 day, pod 1 year. They were analyzed and genial angles were measured. The results were as follows : 1. Gonial angle at pod 1 day was decreased about $9.3^{\circ}$ than pre-op and gonial angle at pod 1 year was increased about $4.0^{\circ}$ than pod 1 day. So genial angle at pod 1 year was decreased about $5.3^{\circ}$ than pre-op genial angle(p<0.01). 2. Mean pre-op gonial angle was $129.4^{\circ}$, showing significantly high value than normal and mean gonial angle at pod 1 year was $124.1^{\circ}$, showing value near to normal. 3. Mean gonial angle change between pre-op and pod 1 year was decreased about $5.4^{\circ}$ in female and $5.3^{\circ}$ in male. There was no statistically significant difference between male and female(p>0.05). 4. Principal factor influencing on decreased gonial angle in gonial angle change between pre-op and pod 1 year was amount of mandibular setback. 5. Principal factor influencing on increased gonial angle in gonial angle change between pod 1 day and pod 1 year was % horizontal relapse, and it was thought that resorption and bone remodelling on posterior area in mandibular distal segment also were related to increased gonial angle. 6. It is thought that sagittal split ramus osteotomy in mandibular prognathic patients with high value of gonial angle is effective to improvement of gonial angle, and In patients who have normal range of gonial angle and are required with excessive mandibular setback, short lingual cut method, additional resection of posterior margin of distal segment, Obwegeser II method will be considerd. 7. More prudent operation and careful post-op management will be responsible for maintenance of postoperative stable gonial angle.

  • PDF

Superoxide Dismutase Gene Expression Induced by Lipopolysaccharide in Alveolar Macrophage of Rat (폐포대식세포에서 내독소 자극에 의한 Superoxide Dismutase 유전자발현의 조절 기전)

  • Park, Kye-Young;Yoo, Chul-Gyu;Kim, Young-Whan;Han, Sung-Koo;Shim, Young-Soo;Hyun, In-Gyu
    • Tuberculosis and Respiratory Diseases
    • /
    • v.42 no.4
    • /
    • pp.522-534
    • /
    • 1995
  • Background: In the pathogenesis of acute lung injury induced by lipopolysaccharide(LPS), oxygen radiclls are known to be involved in one part. Superoxide dismutase(SOD) protects oxygen radical-induced tissue damage by dismutating superoxide to hydrogen peroxide. In eukaryotic cells, two forms of SOD exist intracellularly as a cytosolic, dimeric copper/zinc-containing SOD(CuZnSOD) and a mitochondrial, tetrameric manganese-containing SOD(MnSOD). But there has been little information about SOD gene expression and its regulation in pulmonary alveolar macrophages(PAMs). The objective of this study is to evaluate the SOD gene expression induced by LPS and its regulation in PAMs of rat. Method: In Sprague-Dawley rats, PAMs obtained by broncholaveolar lavage were purified by adherence to plastic plate. To study the effect of LPS on the SOD gene expression of PAMs, they were stimulated with different doses of LPS($0.01{\mu}g/ml{\sim}10{\mu}g/ml$) and for different intervals(0, 2, 4, 8, 24hrs). Also for evaluating the level of SOD gene regulation actinomycin D(AD) or cycloheximide(CHX) were added respectively. To assess whether LPS altered SOD mRNA stability, the rate of mRNA decay was determined in control group and LPS-treated group. Total cellular RNA extraction by guanidinium thiocyanate/phenolfchlorofonn method and Northern blot analysis by using a $^{32}P$-labelled rat MnSOD and CuZnSOD cDNAs were performed. Results: The expression of mRNA in MnSOD increased dose-dependently, but not in CuZnSOD. MnSOD mRNA expression peaked at 8 hours after LPS treatment. Upregulation of MnSOD mRNA expression induced by LPS was suppressed by adding AD or CHX respectively. MnSOD mRNA stability was not altered by LPS. Conclusion: These findings show that PAMs of rat could be an important source of SOD in response to LPS, and suggest that their MnSOD mRNA expression may be regulated transcriptionally and require de novo protein synthesis without affecting mRNA stability.

  • PDF

Comparative evaluation of roughness of titanium surfaces treated by different hygiene instruments

  • Unursaikhan, Otgonbayar;Lee, Jung-Seok;Cha, Jae-Kook;Park, Jung-Chul;Jung, Ui-Won;Kim, Chang-Sung;Cho, Kyoo-Sung;Choi, Seong-Ho
    • Journal of Periodontal and Implant Science
    • /
    • v.42 no.3
    • /
    • pp.88-94
    • /
    • 2012
  • Purpose: The use of appropriate instruments to clean surfaces with minimal change, is critical for the successful maintenance of a dental implant. However, there is no consensus about the type and methodology for such instruments. The aim of this study was to characterize changes in the roughness of titanium surfaces treated by various scaling instruments. Methods: Thirty-seven identical disks (5 mm in diameter) were investigated in this study. The specimens were divided into eight groups according to the types of instrumentation and the angle of application. Ultrasonic scaling systems were applied on a titanium disk to simulate standard clinical conditions. The equipment included a piezoelectric ultrasonic scaler with a newly developed metallic tip (NS group), a piezoelectric ultrasonic scaler with a conventional tip (CS group), a piezoelectric root planer ultrasonic scaler with a conventional tip (PR group), and a plastic hand curette (PH group). In addition, the sites treated using piezoelectric ultrasonic scaler systems were divided two sub-groups: 15 and 45 degrees. The treated titanium surfaces were observed by scanning electron microscopy (SEM), and the average surface roughness (Ra) and mean roughness profile depth (Rz) were measured with a profilometer. Results: SEM no significant changes in the titanium surfaces in the NS group, regardless of the angle of application. The PH group also showed no marked changes to the titanium surface, although some smoothening was observed. All CS and PR sites lost their original texture and showed irregular surfaces in SEM analysis. The profilometer analysis demonstrated that the roughness values (Ra and Rz) of the titanium surfaces increased in all, except the PH and NS groups, which showed roughness decreases relative to the untreated control group. The Ra value differed significantly between the NS and PR groups (P<0.05). Conclusions: The results of this study indicated that changes in or damage to titanium surfaces might be more affected by the hardness of the scaler tip than by the application method. Within the limitations of this study, the newly developed metallic scaler tip might be especially suitable for peri-implant surface decontamination, due to its limited effects on the titanium surface.

Study of Failure Mode and Static Behavior of Lightweight FRP Truss Bridge Deck System (복합재료 트러스 교량시스템의 정적거동 및 파괴모드에 관한 해석적 연구)

  • Jung, Woo-Young;Lee, Hyung-Kil
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.20 no.5
    • /
    • pp.511-520
    • /
    • 2007
  • There is a concern with worldwide deterioration of highway bridges, particularly reinforced concrete. The advantages of fibre reinforced plastic(FRP) composites over conventional materials motivate their use in highway bridges for replacement of structures. Recently, an FRP deck has been installed on a state highway, located in New York State, as an experimental project. In this paper, a systematic approach for analysis of this FRP deck bridge is presented. Multi-step linear numerical analyses have been performed using the finite element method to study the structural behavior and the possible failure mechanism of the FRP deck-superstructure system. Deck's self-weight and ply orientations at the interface between steel girders and FRP deck are considered in this study. From this research, the results of the numerical analyses were corroborated with field test results. Analytical results reveal several potential failure mechanism for the FRP deck and truss bridge system. The results presented in this study may be used to propose engineering design guideline for new and replacement FRP bridge deck structure.

Elemental alteration of the surface of dental casting alloys induced by electro discharge machining (치과용 주조 합금의 방전가공에 따른 표면 성분 변화)

  • Jang, Yong-Chul;Lee, Myung-Kon
    • Journal of Technologic Dentistry
    • /
    • v.31 no.1
    • /
    • pp.55-61
    • /
    • 2009
  • Passive fitting of meso-structure and super-structures is a predominant requirement for the longevity and clinical success of osseointegrated dental implants. However, precision and passive fitting has been unpredictable with conventional methods of casting as well as for corrective techniques. Alternative to conventional techniques, electro discharge machining(EDM) is an advanced method introduced to dental technology to improve the passive fitting of implant prosthesis. In this technique material is removed by melting and vaporization in electric sparks. Regarding the efficacy of EDM, the application of this technique induces severe surface morphological and elemental alterations due to the high temperatures developed during machining, which vary between $10,000{\sim}20,000^{\circ}C$. The aim of this study was to investigate the morphological and elemental alterations induced by EDM process of casting dental gold alloy and non-precious alloy used for the production of implant-supported prosthesis. A conventional clinical dental casting alloys were used for experimental specimens patterns, which were divided in three groups, high fineness gold alloy(Au 75%, HG group), low fineness gold alloy(Au 55%, LG group) and nonprecious metal alloy(Ni-Cr, NP group). The UCLA type plastic abutment patterns were invested with conventional investment material and were cast in a centrifugal casting machine. Castings were sandblasted with $50{\mu}m\;Al_2O_3$. One casting specimen of each group was polished by conventional finishing(HGCON, LGCON, NPCON) and one specimen of each group was subjected to EDM in a system using Cu electrodes, kerosene as dielectric fluid in 10 min for gold alloy and 20 min for Ni-Cr alloy(HGEDM. LGEDM, NOEDM). The surface morphology of all specimens was studied under an energy dispersive X-ray spectrometer (EDS). The quantitative results from EDS analysis are presented on the HGEDM and LGEDM specimens a significant increase in C and Cu concentrations was found after EDM finishing. The different result was documented for C on the NPEDM with a significant uptake of O after EDM finishing, whereas Al, Si showed a significant decrease in their concentrations. EDS analysis showed a serious uptake of C and Cu after the EDM procedure in the alloys studied. The C uptake after the EDM process is a common finding and it is attributed to the decomposition of the dielectric fluid in the plasma column, probably due to the development of extremely high temperatures. The Cu uptake is readily explained from the decomposition of Cu electrodes, something which is also a common finding after the EDM procedure. However, all the aforementioned mechanisms require further research. The clinical implication of these findings is related with the biological and corrosion resistance of surfaces prepared by the EDM process.

  • PDF