Academic literature on the topic 'Fatigue Resistant Device'
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Journal articles on the topic "Fatigue Resistant Device"
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Elkordy, Sherif A., Mona M. Salah Fayed, Khaled H. Attia, and Amr M. Abouelezz. "Complications encountered during Forsus Fatigue Resistant Device therapy." Dental Press Journal of Orthodontics 25, no. 3 (May 2020): 65–72. http://dx.doi.org/10.1590/2177-6709.25.3.065-072.oar.
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ABSTRACT Introduction: Fixed functional appliances are non-compliant solutions to Class II malocclusion treatment. The clinician, however, should be careful of unexpected complications during the therapy. Methods: 58 female adolescents who presented with Class II malocclusion due to deficient mandible were treated with Forsus Fatigue Resistant Device (FFRD) therapy until an overcorrection to an edge to edge incisor relationship was achieved. Results: Incisor relationship and overjet were corrected successfully in all the subjects. Twenty-two patients had a complications-free treatment, while several complications were encountered with the remaining 36 subjects. In particular, mandibular canine rotation and development of posterior crossbites were the most common complications, with percentages of 51.7% and 25.9% respectively. Other complications included the breakage and shearing of the extraoral tubes of the first molar bands, and excessive intrusion of the upper first molars. Conclusions: FFRD is an efficient appliance for treatment of Class II malocclusion; however, different complications were encountered during the appliance therapy. A focus on taking precautions and applying preventive measures can help to avoid such problems, reducing the number of emergency appointments and enhancing the treatment experience with the appliance.
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Bowman, Amy C., Humam Saltaji, Carlos Flores-Mir, Brian Preston, and Sawsan Tabbaa. "Patient experiences with the Forsus Fatigue Resistant Device." Angle Orthodontist 83, no. 3 (October 18, 2012): 437–46. http://dx.doi.org/10.2319/081112-647.1.
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ABSTRACT Objective: To investigate patients' experiences with the Forsus Fatigue Resistant Device (FFRD). Methods: This was a survey focused on patient's comprehensive experience with FFRD, both initially and after several months of wear, including the patient's overall impression of the appliance. The survey was administered to 70 patients wearing FFRD in both university and private practice settings. Results: A high percentage (81.5%) reported a neutral to favorable experience with FFRD; 89.8% reported growing accustomed to the appliance within 4 weeks. The majority of those who had previously worn rubber bands found FFRD to be “easier.” Cheek irritation was the most serious side effect (about 50%). Cheek irritation and other negative effects generally decreased over time. Conclusions: The FFRD is relatively well accepted by patients. Most patients experience some discomfort and functional limitations; however, the effect generally diminishes with time, and patients adapt to the appliance. Practitioners should be especially vigilant about problems with cheek irritation.
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Aslan, Belma I., Ebru Kucukkaraca, Cagri Turkoz, and Mufide Dincer. "Treatment effects of the Forsus Fatigue Resistant Device used with miniscrew anchorage." Angle Orthodontist 84, no. 1 (June 17, 2013): 76–87. http://dx.doi.org/10.2319/032613-240.1.
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ABSTRACT Objective: To evaluate the dentofacial effects of the Forsus Fatigue Resistant Device (FRD) used with miniscrew anchorage (FRDMS) and compare them with those of conventional FRD and an untreated Class II control group. Materials and Methods: The sample consisted of 48 Class II subjects. Sixteen patients (13.68 ± 1.09 years of age) were treated with FRDMS, whereas 17 subjects (14.64 ± 1.56 years of age) were treated with only FRD. Also, a control sample of 15 untreated Class II subjects (14.13 ± 1.50 years of age) was constructed. Angular and linear measurements were made on 96 lateral cephalograms. Paired t, one-way analysis of variance, and Tukey tests were used for statistical analysis. Results: Class I molar relationship and overjet correction were achieved in an average period of 6.5 ± 1.97 and 5.5 ± 1.80 months in the FRDMS and FRD groups, respectively. No skeletal effect was determined in both treatment groups. Greater overbite correction was found in the FRD group. Retrusion and extrusion of maxillary incisors, distalization of maxillary molars, and extrusion of mandibular molars were significant in both treatment groups. Labial tipping of mandibular incisors was significantly greater in the FRD group than in the FRDMS group. Conclusion: Overjet and molar correction was totally dentoalveolar. Unfavorable labial tipping of mandibular incisors was effectively minimized with the usage of miniscrews.
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Jonnalagadda, VenkataNaga Sravanthi, and SB V. Ramana Reddy. "Treatment of Class II division 1 malocclusion using forsus fatigue-resistant device." International Journal of Orthodontic Rehabilitation 9, no. 4 (2018): 168. http://dx.doi.org/10.4103/ijor.ijor_19_18.
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Sood, S., Om Kharbanda, R. Duggal, M. Sood, and S. Gulati. "Muscle Response during Treatment of Class II Division 1 Malocclusion with Forsus Fatigue Resistant Device." Journal of Clinical Pediatric Dentistry 35, no. 3 (April 1, 2011): 331–38. http://dx.doi.org/10.17796/jcpd.35.3.5v86511u4h1mw144.
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Purpose: To evaluate the muscle response in order to determine the mechanism of neuromuscular adaptations with Forsus Fatigue Resistant DeviceTM which has greater elasticity and flexibility; allows greater range of movement of mandible; is available in pre fabricated assembly of springs, tubes and rods and is a simple, effective and reliable corrective appliance that benefits not only growing patients but also malocclusions that previously required extractions, headgears and surgery. Method: Bilateral EMG activity from anterior temporalis and masseter muscles was monitored longitudinally on 10 young growing females with Class II Division 1 malocclusion to determine changes in postural, swallowing, and maximal voluntary clenching over an observation period of 6 months. Results: There was a significant decrease in the muscle activity at one month after Forsus Fatigue Resistant DeviceTM insertion during swallowing of saliva and maximal voluntary clenching which gradually returned to pre treatment levels at the end of six months.Conclusion: This study suggests that Forsus Fatigue Resistant DeviceTM should be given for at least six months to allow for adequate neuromuscular adaptations to occur for long term stability of the result.
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Aras, Isil, and Aylin Pasaoglu. "Class II subdivision treatment with the Forsus Fatigue Resistant Device vs intermaxillary elastics." Angle Orthodontist 87, no. 3 (October 13, 2016): 371–76. http://dx.doi.org/10.2319/070216-518.1.
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ABSTRACT Objective: To compare the effectiveness of comprehensive fixed appliance treatments implemented in combination with Forsus or intermaxillary elastics in Class II subdivision subjects. Materials and Methods: Twenty-eight Class II subdivision patients were allocated to two groups using matched randomization: Forsus group (mean age, 14.19 ± 1.02 years) and elastics group (mean age, 13.75 ± 1.16 years). Patients received fixed appliance therapy in combination with either Forsus or intermaxillary elastics. The study was conducted on lateral cephalograms and digital models acquired before orthodontic treatment and 10–12 weeks after the fixed appliances were removed. Results: The treatment phase comprising the use of Forsus (4.53 ± 0.91 months) was significantly shorter compared with elastics application (6.85 ± 1.08 months). This was also true for comparing duration of overall comprehensive treatment in both groups. Extrusion and palatal tipping of maxillary incisors and clockwise rotation of the occlusal plane were greater in the elastics group (P < .05). The mandibular incisors were proclined in both groups (P < .001), but no significant difference was observed between groups (P > .05). The mandibular incisors showed intrusion in the Forsus group and extrusion in the elastics group; the difference between groups was significant (P < .05). Overbite was decreased in both groups (P < .001) in similar amounts. Improvement in overjet, mandibular midline deviation, and correction of molar relationship on the Class II side were greater in the Forsus group (P < .05). Conclusion: Forsus is more effective for correcting Class II subdivision malocclusion in a shorter treatment period with minimal patient compliance required.
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Li, Hegang, Xun Ren, Yun Hu, and Lijun Tan. "Effects of the Forsus Fatigue-resistant Device on Skeletal Class II Malocclusion Correction." Journal of Contemporary Dental Practice 21, no. 1 (January 2020): 105–12. http://dx.doi.org/10.5005/jp-journals-10024-2748.
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Testarelli, L., N. M. Grande, G. Plotino, M. Lendini, G. Pongione, G. De Paolis, F. Rizzo, V. Milana, and G. Gambarini. "Cyclic Fatigue of Different Nickel-Titanium Rotary Instruments: A Comparative Study." Open Dentistry Journal 3, no. 1 (April 16, 2009): 55–58. http://dx.doi.org/10.2174/1874210600903010055.
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Since the introduction of nickel-titanium alloy to endodontics, there have been many changes in instrument design, but no significant improvements in the raw material properties, or enhancements in the manufacturing process. Recently, a new method to produce nickel-titanium rotary (NTR) instruments has been developed, in an attempt to obtain instruments that are more flexible and resistant to fatigue. NTR instruments produced using the process of twisting (TF, SybronEndo, Orange, CA) were compared to NTR instruments from different manufacturers produced by a traditional grinding process. The aim of the study was to investigate whether cyclic fatigue resistance is increased for TF NTR files. Tests were performed with a cyclic fatigue device that evaluated cycles to failure of rotary instruments inside curved artificial canals. Results indicated that size 06-25 TF instruments showed a significant increase (P< .05). In the mean number of cycles to failurewhen compared to the other tested 06-25 NTR. Hence, it can be concluded that size 06-25 TF NTR instruments were found to be significantly more resistant to fatigue than those produced with the traditional grinding process.
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Goyal, Varun, and US Krishna Nayak. "Treatment of division II malocclusion in young adult with Forsus™ fatigue-resistant device." Indian Journal of Dental Research 23, no. 2 (2012): 289. http://dx.doi.org/10.4103/0970-9290.100444.
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Ren, Yongyuan, Jiangna Guo, Ziyang Liu, Zhe Sun, Yiqing Wu, Lili Liu, and Feng Yan. "Ionic liquid–based click-ionogels." Science Advances 5, no. 8 (August 2019): eaax0648. http://dx.doi.org/10.1126/sciadv.aax0648.
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Gels that are freeze-resistant and heat-resistant and have high ultimate tensile strength are desirable in practical applications owing to their potential in designing flexible energy storage devices, actuators, and sensors. Here, a simple method for fabricating ionic liquid (IL)–based click-ionogels using thiol-ene click chemistry under mild condition is reported. These click-ionogels continue to exhibit excellent mechanical properties and resilience after 10,000 fatigue cycles. Moreover, due to several unique properties of ILs, these click-ionogels exhibit high ionic conductivity, transparency, and nonflammability performance over a wide temperature range (−75° to 340°C). Click-ionogel–based triboelectric nanogenerators exhibit excellent mechanical, freeze-thaw, and heat stability. These promising features of click-ionogels will promote innovative applications in flexible and safe device design.
Dissertations / Theses on the topic "Fatigue Resistant Device"
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Felty, Trista Lee. "THE EFFECTIVENESS OF THE FORSUS FATIGUE RESISTANT DEVICE: A SYSTEMATIC REVIEW." Master's thesis, Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/163830.
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Oral BiologyM.S.
Class II malocclusions affect over twenty percent of the population. Over the years numerous appliances have been invented and modified in order to treat this type of maloclussion. Functional appliances have been advocated for their ability to assist in mandibular growth along with restraint of maxillary growth, as two-thirds of Class II malocclusions are classified with retrognathic. Publications from the following electronic databases were searched: PubMed, Web of Science, Cochrane Library and Science Direct. Searches included any article published until July 13, 2012. Searches were performed under the term "ForsusTM." These searches yielded sixty-one (61) articles. These were reviewed for relevance based on inclusion and exclusion criteria. Articles were excluded if they did not measure the effectiveness of ForsusTM treatment or were not written in English. Seven (7) articles were deemed of relevance with a high quality study design and were included in this study for evaluation. The current literature suggests that Class II treatment with the ForsusTM appliance is an effective and efficient method to treat Class II maloclussions in six months. It produces mainly a restraining effect on maxillary growth, while the Class II molar correction is derived primarily from dentoalveolar changes. Overjet and overbite is reduced through proclination, mesialization and intrusion of the mandibular incisors and retrusion and extrusion of the maxillary incisors. There is also a distalizing and intrusive force on the maxillary first molars which make this appliance ideal for high angle and open bite cases. Some other noted effects are palatal and occlusal plane clockwise rotation and slight expansion of the intermolar widths after treatment. The other obvious advantage is the continuous wear guaranteed by this non compliance method of treatment.
Temple University--Theses
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Heinrichs, Dean. "Treatment effects of the Forsus fatigue resistant device a cephalometric investigation /." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/10930.
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Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains viii, 101 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 83-92).
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Almeida, Filho Roberto Pinto de. "EFEITOS DOS APARELHOS TWIN FORCE BITE CORRECTOR E FORSUS FATIGUE RESISTANT DEVICE NA JUNÇÃO TEMPOROMANDIBULAR E NAS VIAS AÉREAS." Universidade Metodista de São Paulo, 2011. http://tede.metodista.br/jspui/handle/tede/1290.
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Previous issue date: 2011-04-04O objetivo deste estudo prospectivo foi verificar os efeitos dos aparelhos Twin Force Bite Corrector e Forsus Fatigue Resistant Device na junção temporomandibular e nas vias aéreas. Para tanto, foram selecionados 21 pacientes adultos jovens, má oclusão de Classe II 1ª. divisão, bilateral, mínimo de 1/2 Classe II, padrão de crescimento horizontal. Para tanto, a amostra foi dividida em 2 grupos: grupo A, com média de idade inicial de 14,55 anos, tratado com o aparelho ortopédico fixo Twin ForceR por um período médio de 3,7 meses e o grupo B com média de idade inicial de 15,45 anos, tratado com o aparelho Forsus, por um período médio de 7,4 meses, ambos associados à aparelhagem fixa com mecânica straight-wire, prescrição MBT. Os pacientes do grupo A realizaram TCFC em três tempos: T1A (inicial - sem instalação do aparelho), T2A (no dia da i nstalação do aparelho ortopédico fixo), T3A (após a remoção do aparelho ortopédico fixo). Já o grupo 2 realizou TCFC em dois tempos: T2B (no dia da instalação do aparelho ortopédico fixo) e T3B (após a remoção do aparelho ForsusTM). Após a obtenção das imagens 3Dforam realizados cortes sagitais e coronais na ATM para avaliação do tamanho do côndilo e avaliação dos espaços articulares e vias aéreas. Para comparação intergrupos foi utilizado o teste "t" independente e correlação de Pearson e para comparação intragrupos, análise de variância a um critério e teste t pareado. O nível de significância adotado foi de p<0,05%. Não houve alteração significante na avaliação intergrupos, para as dimensões condilares, espaços articulares, e vias aéreas. Por outro lado, na avaliação intragrupo, houve alteração significante no comprimento efetivo da mandíbula (Co-Gn) para o grupo B, supostamente devido a um maior tempo de tratamento, pois houve correlação significante da largura coronal esquerda e direita com Co-Gn, embora clinicamente tenha sido irrelevante. Sendo assim, conclui-se que não houve diferença entre o desempenho dos dois aparelhos estudados na remodelação óssea condilar em pacientes jovens adultos e não houve alteração das vias aéreas após o tratamento com os aparelhos ortopédicos funcionais fixos e Forsus e Twin Force.
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Pupulim, Daniela Cubas. "Estudo comparativo das alterações cefalométricas do tratamento da má oclusão de Classe II com os aparelhos propulsores Jasper Jumper e Forsus Fatigue Resistant Device, associados ao aparelho fixo." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/25/25144/tde-26082016-080322/.
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Objetivo: O objetivo deste estudo foi comparar as alterações cefalométricas de pacientes com má oclusão de Classe II divisão 1 tratados com os aparelhos Jasper Jumper e Forsus Fatigue Resistant Device, associados ao aparelho ortodôntico fixo. Material e métodos: A amostra foi constituída por 124 telerradiografias em norma lateral de 62 indivíduos, os quais foram divididos em 3 grupos: Grupo Experimental 1 (n=22, idade inicial=12,39 anos), tratados por meio do aparelho Jasper Jumper associado ao aparelho fixo, por um período médio de 2,43 anos; Grupo Experimental 2 (n=19, idade inicial=12,43 anos), tratados com o aparelho Forsus associado ao aparelho fixo, com tempo médio de tratamento de 3,54 anos; Grupo Controle (n=22, idade inicial 12,14 anos), observados por um período médio de 1,78 anos. As alterações de todas as variáveis cefalométricas dos grupos experimentais foram anualizadas e, posteriormente, comparadas às alterações das variáveis do grupo Controle, por meio da Análise de Variância e do teste de Tukey. Resultados: Observou-se que ambos os tratamentos apresentaram um efeito restritivo na maxila; não alteraram o desenvolvimento mandibular; melhoraram a relação maxilomandibular; promoveram rotação horária do plano oclusal e um suave aumento da altura facial anteroinferior. Os grupos experimentais apresentaram limitação do desenvolvimento vertical dos molares superiores; inclinação para vestibular e limitação do desenvolvimento vertical dos incisivos inferiores; e extrusão dos molares inferiores. Os incisivos inferiores exibiram maior protrusão no grupo 1 em relação aos demais grupos. Ambos os aparelhos melhoraram significantemente a relação maxilomandibular, os trespasses horizontal, vertical e a relação molar. Os protocolos de tratamento promoveram retrusão dos lábios superiores. O grupo 2 apresentou suave protrusão dos lábios inferiores e os grupos 1 e 3 apresentaram pequena retrusão. Conclusão: Conclui-se que ambos os aparelhos foram eficazes na correção da má oclusão de Classe II.Objective: The aim of this study was to compare the cephalometric changes of Class II division 1 malocclusion patients treated with Jasper Jumper and Forsus Fatigue Resistant Device, associated with fixed appliances. Methods: The sample consisted of 124 lateral cephalograms of 62 individuals, divided into 3 groups: Group 1 (n=22,mean age=12.39 years), treated with the Jasper Jumper appliance associated with fixed appliances for a mean period of 2.43 years; Group 2 (n=19, mean age=12.43 years), treated with the Forsus appliance associated with fixed appliances, with a mean treatment time of 3.54 years; and the Control group (n=22, mean age=12.14 years), followed for a mean period of 1.78 years. The changes of all cephalometric variables in the study groups were annualized and then compared to the changes observed for the Control group, by analysis of variance and Tukey test. Results: It was observed that both treatments presented a restrictive effect on the maxila; did not change the mandibular development; improved maxillomandibular relationship; produced clockwise rotation of the occlusal plane; and a slight increase in lower anterior facial height. Study groups showed limitation on the vertical development of the maxillary molars; buccal tipping and limitation on the vertical development of the mandibular incisors; and extrusion of mandibular molars. The mandibular incisors exhibited greater protrusion in the group 1 compared to other groups. Both appliances provided significant improvement of maxillomandibular relationship, overjet, overbite and molar relationship. Treatment protocols promoted retrusion of the upper lip. Group 2 presented mild protrusion of the lower lip and groups 1 and 3 showed mild retrusion. Conclusion: Both the appliances were effective in the treatment of Class II malocclusion.
Book chapters on the topic "Fatigue Resistant Device"
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Pelton, Alan R., Sean M. Pelton, Tim Jörn, Jochen Ulmer, Dave Niedermaier, Katrazyna Plaskonka, William S. LePage, Payman Saffari, and M. R. Mitchell. "The Quest for Fatigue-Resistant Nitinol for Medical Implants." In Fourth Symposium on Fatigue and Fracture of Metallic Medical Materials and Devices, 1–30. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2019. http://dx.doi.org/10.1520/stp161620180041.
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Gandedkar, Narayan H. "Correction of Class II malocclusion with the bone-anchored Forsus Fatigue Resistant Device." In Skeletal Anchorage in Orthodontic Treatment of Class II Malocclusion, 244–48. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-7234-3649-2.00046-4.
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Kalita, Hridayjit, and Divya Zindani. "A Review on Materials for Orthotic Devices." In Design, Development, and Optimization of Bio-Mechatronic Engineering Products, 208–29. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8235-9.ch009.
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The recent use of fiber-reinforced composites as bio-material in fabrication of orthoses have accelerated the research in finding the most compatible combinations of bio-polymeric composites. The strength, flexibility, biological compatibility, durability, and fatigue strength can be easily altered considering different combinations of polymers and their reinforced structures. In this chapter, a review of the presently used polymeric composites as orthotic materials, their properties, and their applications based on their availability for common people, for a variety of specialized functions, and for the best quality and compatibility factor were discussed. The common orthotic devices mainly used on patients to support weak joints or limbs, materials used, and processing techniques were discussed. Characterization tests for polyethylene composites performed for material properties like ultimate tensile and bending strength, elastic modulus, thermal degradation properties, and surface resistance were discussed, which validates the usability of polyethylene in orthotic fabrication.
Conference papers on the topic "Fatigue Resistant Device"
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Lu, Guo-Quan, Xingsheng Liu, Sihua Wen, Jesus Noel Calata, and John G. Bai. "Strategies for Improving Reliability of Solder Joints on Power Semiconductor Devices." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41993.
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There has been a significant research effort on area-array flip-chip solder joint technology in order to reduce package footprint, enhance current handling capability, and improve heat dissipation. However, there is a lingering concern over cyclic fatigue of solder alloys by thermo-mechanical stresses arising from mismatched thermal expansion coefficients of expansion among the various components of the package. In this paper, some strategies taken to improve the reliability of solder joints on power devices in single-device and multi-chip packages are presented. A strategy for improving solder joint reliability by adjusting solder joint geometry, underfilling and utilization of flexible substrates is discussed with emphasis on triple-stacked solder joints that resemble the shape of an hourglass. The hourglass shape relocates the highest inelastic strain away from the weaker interface with the chip to the bulk region of the joint while the underfill provides a load transfer from the joints. Flexible substrates can deform to relieve thermo-mechanical stresses. Thermal cycling data show significant improvements in reliability when these techniques are used. The design, testing, and finite-element analyses of an interconnection structure, termed the Dimple-Array Interconnect (DAI), for improving the solder joint reliability is also presented. In the DAI structure, a solder is used to join arrays of dimples pre-formed on a metal sheet onto the bonding pads of a device. Finite-element thermo-mechanical analyses and thermal cycling data show that the dimple-array solder joints are more fatigue-resistant than the conventional barrel-shaped solder joints in flip-chip IC packages.
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Aranda-Michel, Edgar, Jooli Han, and Dennis R. Trumble. "Design of a Muscle-Powered Extra-Aortic Counterpulsation Device for Long-Term Circulatory Support." In 2017 Design of Medical Devices Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/dmd2017-3325.
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While great strides continue to be made in the treatment of congestive heart failure using mechanical ventricular assist devices (VADs), several longstanding difficulties associated with pumping blood continue to limit their long-term use. Among the most troublesome has been the persistent risk of clot formation at the blood-device interface, which generally requires VAD recipients to undergo costly — and potentially dangerous — anticoagulation therapy for the duration of the implant. Another serious and persistent problem with long-term use of these pumps is the increased risk of infection associated with the use of percutaneous drivelines. To address these issues we are currently exploring a new approach to blood pump design that aims to solve both these problems by avoiding them altogether. Toward that end, we propose to harness the body’s own endogenous energy stores in order to eliminate the need to transmit energy across the skin. Further, we intend to transfer the energy from this internal power source to the circulation without contacting the blood to obviate the thrombogenic risks imposed by devices placed directly into the bloodstream. To power the implant we will employ a device developed previously by our group called a muscle energy converter (MEC), shown in Figure 1. The MEC is, in essence, an implantable hydraulic actuator powered by the latissimus dorsi (LD) muscle with the capacity to transmit up to 1.37 joules of contractile work per stroke [1]. By training the muscle to express fatigue-resistant oxidative fibers and stimulating the LD to contract in coordination with the cardiac cycle, the MEC captures and transmits this contractile energy as a high-pressure low-volume (5 cc) hydraulic pulse that can be used, in principle, to actuate an implanted pulsatile blood pump. The goal of this research is to use the low-volume output of the MEC to drive a polymer-based aortic compression device for long-term circulatory support. In this context it is important to note that the idea of applying a counterpulsation device around the ascending aorta is not new. Indeed, this approach has been validated by clinical trials recently completed by Sunshine Heart Inc. showing that displacing 20 cc of blood at the aortic root has significant therapeutic benefits [2]. Unfortunately, while the pneumatic ‘C-Pulse’ device solves the blood-contacting problem, it suffers from the same limitations as traditional VADs — i.e., driveline infections. The device described here achieves the same volumetric displacement as the SSH device via geometric amplification of MEC outputs. Thus, through this mechanism we believe the low-volume power output of the MEC can be used to support heart failure patients while addressing the major limitations associated with long-term VAD use.
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Shinohara, Kazunori, Qiang Yu, Takashi Anzawa, and Hideaki Ishii. "High-Accuracy Fatigue Evaluation of Power Devices by Multi-Coupled Analysis." In ASME 2009 InterPACK Conference collocated with the ASME 2009 Summer Heat Transfer Conference and the ASME 2009 3rd International Conference on Energy Sustainability. ASMEDC, 2009. http://dx.doi.org/10.1115/interpack2009-89043.
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To calculate power semiconductor device fatigue with high accuracy, multiphysics analysis comprising electrical, heat, and stress analyses is presented. Power semiconductor devices (e.g., IGBTs) have been widely used in various applications. In particularly, the power semiconductor device (IGBT) becomes important component in vehicle applications. There is a high demand for compact and high-power capacity next-generation vehicles such as electric vehicles and hybrid vehicles. However, it causes the problem such as thermal stress. The reliability of power semiconductor devices has to be investigated by carrying out highly accurate simulations before developing IGBTs. In this paper, the electrical conductivity in silicon (IGBT) is considered as the material parameter. The semiconductor resistance is calculated by voltage distributions in the semiconductor. Comparing the conductivity constant case with the conductivity variation case, we examine the effects of the electrical characteristics of the semiconductor on fatigue.
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Sugihara, Hiromi, Masanori Yamagiwa, Masato Fujita, Toshikazu Oshidari, and Qiang Yu. "Thermal Fatigue Reliability of High-Temperature-Resistant Joint for Power Devices." In ASME 2009 InterPACK Conference collocated with the ASME 2009 Summer Heat Transfer Conference and the ASME 2009 3rd International Conference on Energy Sustainability. ASMEDC, 2009. http://dx.doi.org/10.1115/interpack2009-89342.
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The power electronics equipments for Electric vehicles such as the inverter are strongly demanded on downsizing and weight reduction. For these requirements, Silicon Carbide (SiC) devices are receiving particular attention. SiC devices are characterized by lower-loss and higher temperature operation compared with Si devices. Using the devices under high temperature, the cooling equipments can be miniaturized. However, a function of stress relaxation that the existing solder has is difficult to be expected in a high-temperature-resistant joint layer for SiC devices, because the joint layer is generally hard. So, the authors have proposed a new mounting structure that a metal circuit on a substrate has the function instead of the joint layer. In this study, high-temperature-resistant mounting structures that the chip was bonded by low temperature sintering method using Ag nano-particles to substrate with Ag/Ni plating are prepared. Thermal Cycle Test (TCT) using these samples of harsh temperature range was conducted. As a result a new critical issue on the chip joint was identified. To clarify the thermal fatigue mechanism, the Finite-Element-Analysis (FEA) was carried out. The analysis model simulated a thin layer of Ag/Ni plating and the high-temperature-resistant joint layer. By the FEM results, the thermal fatigue, particularly occurring crack, was affected by the micro structures.
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Hiramitsu, Shinji, Hiroshi Shintani, Takahiro Satake, and Hisashi Tanie. "Effect of Heat Generation on Fatigue-Crack Propagation of Solder in Power Devices." In ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/ipack2011-52247.
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Power devices are used in inverters in a variety of electrical equipment, for instance, hybrid-power cars, electric vehicles, and generators. These types of equipment are used to decrease the negative impact on the environment, and thus, the power devices need to function effectively as electric power converters for the long-term stability of the equipment. In short, the long-term reliability, i.e., the life, of the power device is important, and a high level of reliability is required. In the development process of power devices, it is necessary to conduct thermal fatigue tests to evaluate the reliability. However, such tests are extended over a long period of time, which makes it difficult to shorten the development period. Therefore, a simulation technique needs to be developed to forecast the life of a thermal fatigue test in order to reduce the development period. During the thermal fatigue test, thermal stress is caused by differences in the line expansion coefficient between solder joint materials. Thermal stress causes crack generation and propagation in solder. The thermal resistance of a device increases steadily as the cracks grow. This raises the temperature of the device and increases thermal stress. As a result, crack propagation is accelerated. However, conventional crack propagation analysis does not take this phenomenon into account. We developed a method of crack propagation analysis that takes into account the changes in thermal and electrical boundary conditions resulting from the crack propagation. The method is a combination of electrical conduction analysis, heat transfer analysis, and crack propagation analysis. The boundary condition of the heat transfer analysis is determined from the results of the electrical conduction analysis. The boundary condition of the crack propagation analysis is determined from the results of the heat transfer analysis. The crack propagation behavior in solder is calculated by repeating these analyses. This method reproduces the drastic increase in thermal resistance in the latter part of the thermal fatigue test, and the results agree well with the experimental results. We confirmed that the temperature distribution of the device changes as the crack propagates and that thermal and electrical coupled analysis has a major effect on the prediction of fatigue life of power device products. We also revealed that the thermal fatigue life is affected by the position of the heat source and cracks.
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James, Erik, Jamil Grant, Michael Alberter, Nastassja Dasque, Cynthia Price, and William J. Craft. "Nickel-Titanium Shape Memory Alloy Motors and Electromechanical Devices." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15119.
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Shape memory alloys (SMA) have been an extensively used material for actuators in micro-electromechanical systems (MEMS) because actuation force and displacement are greatest in SMA amongst many actuator materials [1]. Of the alloys currently available for SMA actuators, the most popular system is Nitinol (or NiTi) due to its good oxidation resistance, reversible martensitic transformation, broad range of transformation temperatures (from -100 - 100 °C), and specific power density [2]. Current commercially available SMA wire has easily achieved no-load strain of 5% with medium gage SMA wires demonstrating an axial force capacity of 2 Newtons or more. While the potential use of SMA materials in a thermal-electric motor has been documented beginning in the 1980's, there are a number of new allows and fatigue-resistant materials that may lead to more general designs with a wide range of motions and applications. Shape memory alloys are a special type of material that exhibit two unique properties, pseudo-elasticity and shape memory effect (SME). SMA undergoes SME because of martensitic or diffusionless transformation where each atom has a slight displacement, creating observable changes throughout the structure as the allow changes states. This alloy has the ability, once heated, to return to its parent austenite phase where it exists at higher symmetry. Upon cooling, the material returns to one of many lower symmetry martensitic phases. This thermal cycle is shown in Figure 1. [3,4]. It is even possible for many variants of martensite to be present in the same material. Pseudo-elasticity is a rubber-like flexibility that allows the SMA to be contorted for a variety of purposes. Once contorted, the application of heat will cause the alloy to undergo martensitic transformation. Upon completion of the cycle, the alloy will have returned to its original shape. The development of SMA-based electromechanical devices delivers traditional mechanical motion with non-traditional methods. Rather than electromagnetic components rotating about a central axis to produce power, the rotary SMA motor utilizes contracting elements, and mush as spark ignition rotary engine, it can be designed to produce angular motion. Motion is accomplished with sequenced electrical signals sent across each element mounted between an eccentric crank. Rotary motion is produced during the power portion of the cycle for specific SMA elements under the application of an electrical signal. Based on this concept, our team developed a demonstration model with four active elements. We have demonstrated rotary motion of the device for an extended period of time, and we believe that macro-scale models can reduce the concept substantially and perhaps to the MEMS level.
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Miyazaki, Hiroyuki, You Zhou, Kiyoshi Hirao, Shinji Fukuda, Noriya Izu, Hideki Hyuga, Shoji Iwakiri, and Hideki Hirotsuru. "Highly thermal-fatigue resistant Si3N4 substrates with excellent mechanical and thermal properties." In 2017 29th International Symposium on Power Semiconductor Devices and IC's (ISPSD). IEEE, 2017. http://dx.doi.org/10.23919/ispsd.2017.7988972.
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Samoylova, Elena, Marco Allione, Alberto Diaspro, Roberto Cingolani, and Athanassia Athanassiou. "Characterization of fatigue resistance property of photochrome materials for optical storage devices." In 2010 IEEE 10th Conference on Nanotechnology (IEEE-NANO). IEEE, 2010. http://dx.doi.org/10.1109/nano.2010.5697919.
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Van Citters, D. W., F. E. Kennedy, J. H. Currier, and J. P. Collier. "Wear Evaluation of Crosslinked UHMWPE for Knee Prostheses Using a Multi-Station Rolling-Sliding Tribotester." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63533.
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Tribology-related failure of total knee replacement prostheses can lead to risky and expensive revision surgery. Recent changes in polyethylene processing may reduce the incidence of, or even eliminate contact fatigue failure related to bearing oxidation, but devices are still subject to failure modes relating to wear or non-oxidation related fatigue. Contemporary materials claim wear reduction and improved oxidation resistance through various crosslinking and annealing steps, but clinical wear performance of these materials in the knee is difficult to determine. A device incorporating clinically relevant motions and stress states has been used in this work to compare the wear properties of crosslinked polyethylene materials subjected to different irradiation and sterilization conditions. It can potentially be used to analyze the wear behavior of polyethylene materials from different manufacturers, allowing for better prediction of relative performance in vivo.
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Yonemaru, M., A. Shimizu, S. Matsuda, and I. Seo. "The Identification of Thermal Fatigue Testing Method of Soldered Joints for Space Use." In ISTFA 1997. ASM International, 1997. http://dx.doi.org/10.31399/asm.cp.istfa1997p0091.
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Abstract Electronic devices have been used under various thermal conditions in space applications. The temperature range often exceeds 100°C, and the electronic devices are stressed by both high and low temperatures and thermal cycles. Since repairing and reworking of the spacecraft electronic hardware cannot be performed after launch, verifying the reliability of the hardware on the ground before the launch is essential. The thermal stresses to the electronic devices' soldered joints have recently tended to increase because the devices must be made smaller and lighter. The thermal fatigue of the soldered joints must be addressed in order to achieve highly reliable flight hardware. We studied a test method to estimate the thermal fatigue life of soldered joints for space use. This paper examines the thermal fatigue life using two kinds of test methods as heat-resistant evaluation tests of soldered joints for space use, and evaluates the effect of the test parameters on the thermal fatigue life of soldered joints. We conclude that the thermal fatigue life of soldered joints cannot be estimated accurately, if the test parameters are instituted uniformly.