24 research outputs found
DEVELOPMENT OF A NEW FATIGUE TESTING MACHINE FOR HIGH FREQUENCY FATIGUE DAMAGE ASSESSMENT
Get PDFABSTRACT A new simple fatigue testing machine, which can carry out fast and low-cost fatigue tests of welded joints subject to wave with high frequency vibration, has been developed. This machine is designed for plate bending type fatigue tests, and wave load is applied by using motors with eccentric mass. Springing vibration is superimposed by attaching an additional vibrator to the test specimen, and whipping vibration is superimposed by an intermittent hammering. Fatigue tests which simulate springing and whipping by a conventional servo-type fatigue testing machines are very expensive and use a large amount of electricity. If one uses these conventional machines, it is difficult to simulate superimposed stress wave forms at high speed, and it takes long hours of testing to examine the high frequency effect. In contrast, it is found that fatigue tests can be carried out in fast, i.e. waves with 10Hz or higher frequency for out-of-plane gusset welded joint specimens with 12mm plate thickness by using the developed machine. The electricity to be used for fatigue tests could be minimal, for example one thousandth of that needed for conventional machines. These results demonstrate the superiority of the developed machine
The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016)
Get PDFBackground and purposeThe Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in February 2017 and published in the Journal of JSICM, [2017; Volume 24 (supplement 2)] https://doi.org/10.3918/jsicm.24S0001 and Journal of Japanese Association for Acute Medicine [2017; Volume 28, (supplement 1)] http://onlinelibrary.wiley.com/doi/10.1002/jja2.2017.28.issue-S1/issuetoc.This abridged English edition of the J-SSCG 2016 was produced with permission from the Japanese Association of Acute Medicine and the Japanese Society for Intensive Care Medicine.MethodsMembers of the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine were selected and organized into 19 committee members and 52 working group members. The guidelines were prepared in accordance with the Medical Information Network Distribution Service (Minds) creation procedures. The Academic Guidelines Promotion Team was organized to oversee and provide academic support to the respective activities allocated to each Guideline Creation Team. To improve quality assurance and workflow transparency, a mutual peer review system was established, and discussions within each team were open to the public. Public comments were collected once after the initial formulation of a clinical question (CQ) and twice during the review of the final draft. Recommendations were determined to have been adopted after obtaining support from a two-thirds (>â66.6%) majority vote of each of the 19 committee members.ResultsA total of 87 CQs were selected among 19 clinical areas, including pediatric topics and several other important areas not covered in the first edition of the Japanese guidelines (J-SSCG 2012). The approval rate obtained through committee voting, in addition to ratings of the strengths of the recommendation, and its supporting evidence were also added to each recommendation statement. We conducted meta-analyses for 29 CQs. Thirty-seven CQs contained recommendations in the form of an expert consensus due to insufficient evidence. No recommendations were provided for five CQs.ConclusionsBased on the evidence gathered, we were able to formulate Japanese-specific clinical practice guidelines that are tailored to the Japanese context in a highly transparent manner. These guidelines can easily be used not only by specialists, but also by non-specialists, general clinicians, nurses, pharmacists, clinical engineers, and other healthcare professionals
2D numerical modeling of icebreaker advancing in ice-covered water
No full textThis paper presents 2D numerical modeling to calculate shipâice interactions that occur when an icebreaker advances into ice-covered water. The numerical model calculates repeated icebreaking of an ice plate and removal of small ice floes. The icebreaking of the ice plate is calculated using a shipâice contact detection technique and fluidâstructural interaction of ice plate bending behavior. The shipâice interactions in small ice floes are calculated using a physically based modeling with 3DOF rigid body equations. The ice plate is broken in crushing, bending, and splitting mode. The ice floes drift by wind or current and by the force induced by the shipâice interaction. The time history of ice force and ice floe distribution when an icebreaker advances into the ice-covered water are obtained numerically. Numerical results demonstrate that the time history of ice force and distribution of ice floes (ice channel width) depend on the ice floe size, ship motion and ice drifting by wind or current. It is shown that the numerical model of ship maneuvering in realistic ice conditions is necessary to obtain precise information about the ship in ice-covered water. The proposed numerical model can be useful to provide data of a ship operating in ice-covered water. Keywords: Ice management, Ice-covered water, Icebreaking, Numerical simulatio
Study on the relationship between the heat transfer characteristics of preheating gas and cutting performance of oxyfuel gas cutting
Full text linkStudy on the Combustion Model and Turbulent Model for Thermal-Flow Analysis of Impinging Jet Flame during line Heating Process
No full textDevelopment of a New Fatigue Testing Machine for High Frequency Fatigue Damage Assessment
Full text linkA new simple fatigue testing machine, which can carry out fast and low-cost fatigue tests of welded joints subject to wave with high frequency vibration, has been developed. This machine is designed for plate bending type fatigue tests, and wave load is applied by using motors with eccentric mass. Springing vibration is superimposed by attaching an additional vibrator to the test specimen, and whipping vibration is superimposed by an intermittent hammering.
Fatigue tests which simulate springing and whipping by a conventional servo-type fatigue testing machines are very expensive and use a large amount of electricity. If one uses these conventional machines, it is difficult to simulate superimposed stress wave forms at high speed, and it takes long hours of testing to examine the high frequency effect. In contrast, it is found that fatigue tests can be carried out in fast, i.e. waves with 10Hz or higher frequency for out-of-plane gusset welded joint specimens with 12mm plate thickness by using the developed machine. The electricity to be used for fatigue tests could be minimal, for example one thousandth of that needed for conventional machines. These results demonstrate the superiority of the developed machine.</jats:p
Experimental Study on High Frequency Effect on Fatigue Strength of Welded Joints by Using Plate-Bending-Vibration Type Fatigue Testing Machines
Full text linkFatigue strength of out-of-plane gusset welded joints subject to springing and whipping superimposed wave loadings is examined by using Plate-Bending-Vibration (PBV) type fatigue testing machines developed in the previous reports [Osawa, N. et al. (2013) Proc. OMAE2013, Paper OMAE2013-11582, Osawa N. et al. (2013) Proc. PRADS2013, pp.550â556]. Springing vibration is superimposed by attaching an additional vibrator to the test specimen, and whipping vibration is superimposed by intermittent hammering. âEnlargement countingâ method, in which the stress history is approximated by a waveform with the low frequency componentâs period and the enlarged total amplitude, is proposed. Fatigue damages and equivalent stress ranges are calculated by enlargement and rainflow cycle counting methods. It is found that the fatigue life under high frequency superimposed loads can be predicted with acceptable accuracy by the modified Miner rule when enlargement or rainflow stress counting is performed and the S-N curve is modified so that it fits the equivalent stress rangeâs Ps = 50% curve. Based on test results, a simplified assessment method for high frequency effect on fatigue strength of shipâs welded joints is proposed. The validity of the proposed assessment method should be further examined by carrying out fatigue tests with realistic stress histories which emulate intermittent occurrence of springing and whipping in ship structure.</jats:p
