• Title/Summary/Keyword: Tool-sheet interaction

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Study on Formability Enhancement of Electromagnetic Forming using Gurson Plasticity Material Model (Gurson모델을 사용한 전자기성형의 성형성 개선에 대한 연구)

  • Kim, Jeong;Song, Woojin;Kang, Beomsoo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.3
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    • pp.98-104
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    • 2013
  • The effect of the tool-sheet interaction on formability enhancement in electromagnetic forming is investigated using FEM. A free bulging and a conical forming die with 0.7mm AL1050 sheet are used to evaluate damage evolution based on Gurson-Tvergaard-Needleman plasticity material model. The impact between the tool and sheet results in complex stress states including compressive hydrostatic stresses, which leads to a suppression of void growth and restrain ascending void volume fraction of the sheet. Therefore, the damage suppression due to the tool-sheet interaction can be the main factor contributing to the increased formability in the electromagnetic forming process.

Prediction of the Formability Enhancement from Electromagnetic Forming due to Interaction between Tool and Blank Sheet (전자기 성형시 금형과 소재의 접촉에 따른 성형성 개선 예측)

  • Lee, Y.H.;Kim, H.K.;Noh, H.G.;An, W.J.;Kim, J.
    • Transactions of Materials Processing
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    • v.24 no.3
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    • pp.199-204
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    • 2015
  • Electromagnetic Forming is a high speed forming technology which uses electromagnetic (Lorentz’s) forces to shape sheet metal parts. In the current study the effect of the tool-sheet interaction during electromagnetic forming on formability enhancement is investigated using FEM. The decrease in void volume fraction by having the sheet contact with die helps to improve formability. The main purpose of the current study was to predict improvement of formed sheets whether the sheet contacts or does not contact the die under experimental conditions and 3-D finite element analysis. The results show that fractures caused by the voids in the forming sheet appear only in some specific cases and the bulge height of the conical shape was shorter than the height with a free bulge. For the same height conditions, however, the formability was improved for the conical-shaped die when there is sheet contact with the die.

Effect of Circumferential Tool Path Control on Friction Stir Spot Welding of Al/Fe Dissimilar Metal Joint (툴 경로제어를 이용한 Al/Fe 이종금속 마찰교반점용접 공정특성 평가)

  • Yoon, Jin Young;Kim, Cheolhee;Rhee, Sehun
    • Journal of Welding and Joining
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    • v.34 no.3
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    • pp.6-11
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    • 2016
  • Joining Al/Fe dissimilar metals is becoming a subject of special interest in the assembly of automotive parts as a trade-off between the weight lightening and the cost reduction. Although various studies have been introduced to join Al alloy with the steel sheet by fusion welding, weak joint strength and galvanic corrosion still remained as problems to be solved. As a solid state welding, friction stir welding has been preferred to fusion welding processes in the dissimilar metal joints. This study investigated friction stir spot welding (FSSW) of Al alloy to the thin steel sheet with a thickness of 0.65 mm. The conventional FSSW is a stationary spot welding process but new approach adopted an additional circumferential movement in company with high speed tool rotation. A full factorial experimental design was implemented, and the main and interaction effects of parameters were analysed on the failure load in the tensile shear test. The direction and radius of rotation were statistically significant parameters and these two parameters affected the joint width and the shape of the hook.

Sectional analysis of stamping processes using Equilibrium approach (평형해법에 의한 스탬핑 공정의 단면 해석)

  • Yoon, J.W.;Yoo, D.J.;Song, I.S.;Yang, D.Y.;Lee, J.H.
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.4
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    • pp.58-68
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    • 1994
  • An equilibrium approach is suggested as an effective tool for the analysis of sheet metal forming processes on the basis of force balance together with geometric relations and plasticity theroy. In computing a force balance equation, it is required to define a geometric curve approximating the shape of the sheet metal at any step of deformation from the geometric interaction between the die and the deforming sheet. Then the geometic informations for contacting and non-contacting sections of the sheet metal such as the number and length of both non-contact region, contact angle, and die radius of contact section are known from the geometric forming curve and utilized for optimization by force balance equation. In computation, the sheet material is assumed to be of normal amisotropy and rigid-phastic workhardening. It has been shown that there are good agreements between the equilibrium approach and FEM computation for the benchmark test example and auto-body panels whose sections can be assumed in plane-strain state. The proposed equilibrium approach can thus be used as a robust computational method in estimating the forming defects and forming severity rather quickly in the die design stage.

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Effect of a PNF Intervention Strategy with the ICF Tool Applied to a Patient with Bilateral Total Hip Replacement Walking a Crosswalk (양측 엉덩관절 전치환술 환자의 횡단보도 걷기 개선을 위해 ICF Tool을 적용한 PNF 중재전략: 사례보고 )

  • Jin-cheol Kim;Jae-heon Lim
    • Journal of the Korean Society of Physical Medicine
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    • v.19 no.1
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    • pp.95-105
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    • 2024
  • PURPOSE: This study aimed to utilize the International Classification of Functioning, Disability, and Health (ICF) tool to identify a problem list and explore intervention effects using proprioceptive neuromuscular facilitation (PNF) for improving the crosswalk performance of patients who have undergone a bilateral hip arthroplasty. METHODS: The subject of this study was a 43-year-old male who had undergone a bilateral hip arthroplasty. To address the subject's functional status, a clinical decision-making process was carried out in the order of examination, evaluation, diagnosis, prognosis, intervention, and outcome. Patient information during the examination was collected using the ICF core set. The evaluation involved listing the items of each problem using the ICF assessment sheet and identifying the interaction between activity limitations and the impairment level. The diagnosis explicitly described the causal relationships derived from the evaluation using ICF terminology. The prognosis presented activity goals, body function, and structured goals in terms of the activity and participation levels that needed to be achieved for an individual's functional status. The intervention approached problems through the four components of the PNF philosophy, namely basic principles and procedures, techniques, and patterns, in an indirect-direct-task sequence. Results were compared before and after the intervention using the ICF evaluation display. RESULTS: The results of the study showed that the primary activity limitation, which was the walking time across the crosswalk, showed improvement, and the trunk's counter rotation and the weight-bearing capacity of both the lower limbs, which were impairment level indicators, were enhanced. CONCLUSION: This study suggests that PNF intervention strategies will serve as a positive approach for improving crosswalk walking in patients with bilateral hip arthroplasty.

A Phenomenological Study on Mother-Infant Interacting Behavior Patterns Related to Newborn Infant Feeding in Korea (한국인 영아초기 수유시 모아상호작용 행동형태에 관한 현상학적 연구)

  • 한경자
    • Journal of Korean Academy of Nursing
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    • v.21 no.1
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    • pp.89-116
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    • 1991
  • The purpose of this study was to describe mother -infant interacting behavior patterns related to newborn infant feeding and to explore the mother's cultural belief about their infant. The data collection was conducted by observation and interview. Twenty-five mothers and their newborn infants who were normally delivered and were also planned to breast feed were comprised as the subjects of this study. All subjects were interviewed and observed individuaily at 1 to 5 days after the delivery at the hospital, mid -wife's clinic, Maternal Child Health Center and their home throughout the country from remote area to big city, The observation data were recorded with symbolic letter on a recording sheet newly developed as a result of preliminary study. The interview data were taperecorded and then recorded in narrative form. Mother - infant interaction behaviors in early feeding period were analyzed based on 19 analytic sub-categories and their composing elements. Unit of analysis were mother, infant and mother -infant dyad. 8 analytic categories draw from the data. Each were preparation, instrument, interaction inducing, evaluation referred to mother's behavior, preparation, instrument, interaction inducing referred to infant's behavior and synchronic behaviors referred to mother - infant dyad. Frequencies of behavior items based on the categories were converted to percent. The result showed that in mother's preparation behavior, the breast condition of Korean mother can be an affecting factor for mother - infant interaction during feeding, and vocalization behavior was observed most frequently in interaction inducing behavior while the least frequent behavior observed was contacting. Subcultural characteristics of mother - infant interaction behaviors were analyzed for their relationships between groups of mothers who have lived in remote area vs urban area, and who were multipara vs primipara. Using a chi -square test, there were statistically significant relationships in the activity of psychological readiness in preparation behavior and the movement of extremities for the position of instrumental behavior in both groups. However, interaction inducing behaviors were not related with statistical significance in any set of groups. Accomplishment of marriage, bonding and emotional mediation of family members were the categories related to mother's cultural belief about the infant in aspect of functional values. Infant at birth is considered little more than a biological organism without social capabilities. Although the newborn infant is still be attached to his mother, he makes his mother extend her territoriality. The mother's interacting behavior toward her infant based on those beliefs appeared task oriented, separative behavioral series. On the other hand, it was seen that infant reacted independently to his mother's behavior by the in-nate perceptual abilities. Those independent behavioral series of mother and infant on the feeding situation were synchronized at any moment. Nurses are In a unique position to teach mothers about their infant's capabilities and help reducing some of uncertainty about infant's behaviors. Study results indicated that the informations infant's social capabilities and breast feeding should be given to the mothers. The results of this study have several implications for nursing. First, the study results will be used as fundamental resources for the development of the assessment tool about the early mother - infant interaction. Second, the results could be a relevant information in the fied. I of maternal child nursing education as real and useful data. Third, the behavioral patterns of early mother - infant interaction which were classified based on the qualitative analysis could be used for nursing theory development as very fundamental data.

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ICF Tool applied Intervention Strategy and Charting on Upper Extremity Functional Recovery of the Frozen Shoulder Patient - Case Study (동결견 환자의 상지 기능 회복에 대한 ICF Tool을 적용한 중재 전략과 문서 기록-사례연구)

  • Kong, Sun-Woong;Lim, Hyoun-Chyoul;Jung, Yeon-Woo
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.17 no.1
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    • pp.35-44
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    • 2011
  • Background: This study was to suggest the process of making strategy for effective intervention and evaluation on functional problems of the frozen shoulder patient applied International Classification of Functioning Disability and Health (ICF) Tools. Methods: The patient was 48years old woman with right shoulder adhesive capsulitis and calcific tendinitis. In first phase, therapists could list the information relating to functional problems used by the ICF Core set and then could confirm the interaction among the problems using the ICF assessment sheet. In second phase, therapist is needed to make the hypothesis and hypothesis testing and then set a primary functional goals and therapeutic goals in detail after prioritizing the problems to be managed based on the problem list. Lastly, after setting the confirmed problems as the purpose of intervention through the hypothesis testing, therapist could do some intervention after making a plan to solve these problems. Results: This report illustrates how to apply the process based on ICF concept into physical therapy practice. The decided hypothesis and goal that are to solve the problems the client faced were remarkably meaningful. Conclusions: Clinical decision making for the most effective intervention requires that therapists use the clinical reasoning process based on ICF concept.

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A PNF Intervention Strategy with ICF Tool Applied for Improvement of Dressing in a Patient with Rotator Cuff Syndrome : A Case Report (회전근개 파열 환자의 옷입고 벗기 향상을 위해 ICF Tool을 적용한 PNF 중재전략 : 증례보고)

  • Kim, Jin-Cheol;Lee, Jeong-A
    • Journal of the Korean Society of Physical Medicine
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    • v.13 no.3
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    • pp.49-60
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    • 2018
  • PURPOSE: This study was conducted to investigate the intervention effect obtained by applying an ICF tool to improve the dressing in a patient with rotator cuff syndrome to schematize the problems and approaching with PNF to solve the problems. METHODS: The subject of this study was a 44-year-old patient who underwent surgery after complete right rotator cuff tear. To treat his symptoms, the processes of clinical practice were implemented in the order of examination, assessment, diagnosis, prognosis, intervention, and outcome. During examination, patient information was collected using the ICF core set. In the assessment, the problems were schematized, and an ICF assessment sheet was used to identify the interaction of the problems. The diagnosis was made by clearly describing the causal relationship derived from the assessment in ICF terms. To solve the problems, the intervention was given in the order of indirect, direct, and task based on the philosophy of PNF. To evaluate the outcome, the differences before and after the intervention were compared. Additionally, the comparison for the ICF qualifier is presented with the ICF evaluation display. RESULTS: The results of the study showed clinical advantages in shoulder strength, eccentric control, range of motion, scapular stability, and shoulder pain. Overall, our patient with rotator cuff syndrome showed improvement in dressing and undressing activity in response to the PNF strategy. CONCLUSION: Application of the PNF intervention strategy after complete rotator cuff tear would have a positive effect on patient upper extremity function.

A Case Report of Intervention Strategy applied ICF Tool about Floor to Stand and Stand to Floor for Stroke Patient (ICF Tool을 적용한 뇌졸중 환자의 바닥에 앉고 일어서기에 대한 중재전략의 증례)

  • Yun, Tae-Won;Kim, Tae-Yoon
    • Journal of Korean Physical Therapy Science
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    • v.18 no.1
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    • pp.33-49
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    • 2011
  • The process of physical therapy uses a problem-solving approach to enhance a patients's functioning status. The International Classification of Functioning, Disability and Health(ICF) is the common concept for the functioning in the world. Physical therapists require the ability to identify problems, formulate hypothesis, and plan intervention strategies through clinical reasoning. In the clinical process, physical therapists need to use standard and common languages in speech and in documentation. The purpose of this study was to suggest the process of making strategy for efficient intervention, examining and evaluating the functional problem of the person with stroke using ICF tools. For the first step in this process model, therapists could list the information relating to functional problems used by the ICF Core set and then could identify the interaction among the problems using the ICF assessment sheet. For the next step, therapist is needed to make the hypothesis and hypothesis testing, and then set a primary functional goals and therapeutic goals in detail after prioritizing the problems to be managed based on the problem list. Finally, after setting the identified problems as the purpose of intervention through the hypothesis testing, therapist could do some intervention after making a plan to solve these problems, and find out the outcomes using the ICF evaluation display. This report illustrates how to apply the process based on ICF concept into physical therapy practice. Making a decision for the most efficient intervention requires that therapists use the clinical reasoning process based on ICF concept.

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The Coordinative Locomotor Training Intervention Strategy Using the ICF Tool to Improve the Standing Posture in Scoliosis: A Case Report

  • Lee, Jeong-a;Kim, Jin-cheol
    • The Journal of Korean Physical Therapy
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    • v.33 no.1
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    • pp.7-15
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    • 2021
  • Purpose: This study was examined to improve the standing posture of a scoliosis client using the ICF Tool. Methods: For examination, the study subject was a 16-year-old female student diagnosed with 3curve-pelvic (3CP) type scoliosis. Information about her were collected through a client interview and based on international Classification of Functioning, Disability and Health (ICF). The ICF core set was for post-acute musculoskeletal conditions, and the ICF level 2 items suggested by National Rehabilitation Information Center (NARIC) were added to the recommendations for scoliosis. For evaluation, the ICF assessment sheet was used to identify the interaction among the problems. For the diagnosis, the client's functional problems were described in ICF terms. For the prognosis, the global goals for reaching the client's functional activity and participation level were presented as the long-and short-term goals. For the intervention, a coordinative locomotor training program composed of warm-up, main exercise, and cool-down was applied 3 times a week, 50 minutes a day, for 5 weeks. For the outcome, the differences between before and after the intervention were compared with the ICF qualifier and are shown with the ICF evaluation display. Results: Clinical advantages were observed in body function and structure (7° decrease of thoracic angle, 7 score increase of trunk muscle power, 6.47s improve of one leg standing, 4 score decrease of neck pain). The activity for maintaining the standing posture, in which the client had a primary limitation, was improved. Conclusion: Applying the coordinative locomotor training program is expected to improve scoliosis client's standing posture.