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  • 仲 威雄
    建築學會論文集
    1938年 9 巻 167-170
    発行日: 1938年
    公開日: 2017/12/04
    ジャーナル フリー
    本論文は衝合熔接の熱變形並に熔接熱應力に關する基本的實驗事實を報告せるものである。
    拘束
    を與へない即ち自由なる板の變形と
    拘束を與へたる板の變形とは拘束
    の性質並に程度に應ずる差を見るものであつて本實驗に於ける如き
    拘束
    を加へる時は概して變形量小となるが
    拘束
    部の性質によつては彎曲變形は寧ろ大となることさへある。著者は數種の試驗體に就いて種々の
    拘束條件を變へて拘束條件と變形との相互關係を索め最後に拘束
    が接手の強さに及す影響を調査した。
  • 上田 幸雄, 福田 敬二, 金 裕哲
    溶接学会誌
    1982年 51 巻 8 号 644-650
    発行日: 1982/08/05
    公開日: 2011/08/05
    ジャーナル フリー
    Welded structures are inevitably accompanied by deformation and residual stresses produced by construction, which sometimes cause initiation of various types of weld cracking. In order to avoid the weld cracking, the y-Groove cracking test specimen has been widely used as the cold cracking sensitivity specimen to determine appropriate materials and welding conditions.
    In this paper, the dynamical characteristics of the y-Groove cracking test specimen of arbitrary thickness are clarified by discussing the restraint stresses and strains produced in this specimen for general cases of welding where the size of the specimen changes and heat input varies. The results are as follows:
    (1) For evaluation of restraint stresses and strains produced perpendicular to the weld line in the weld metal of a y-Groove cracking test specimen, the analytical calculation method which was already presented for comparatively thin plates is extended for thicker plates. Then, the restraint stresses and strains under the influence of the ratio of plate thickness to throat thickness can be analytically calculated without conducting three dimensional elastic-plastic analysis.
    (2) The magnitude of restraint stresses and strains produced in a slit weld specimen vary with the amount of heat input, that is, they are dependent on the ratio of l/hcr. Judging the severity of the dynamical condition of the specimen from the magnitude of restraint stresses and strains, the infinite plate is the severest. The infinite plate may be replaced by a finite plate of which size ratio is (B/l≥4.0, L/l≥3.7). Then, the size ratio of the y-Groove cracking test specimen is not necessarily the severest.
    (3) Among the slit weld specimens with the same size ratio as the y-Groove cracking test specimen, the actual size of the y-Groove cracking test specimen achieves the severest dynamical condition for the specific heat input Q=17000J/cm.
    (4) When the thickness of the y-Groove cracking test specimen increases, the restraint strain (the sum of the elastic and plastic components) produced in the weld metal of the first pass also increases. However, the increasing tendency saturates at the plate thickness of approximately h=50 mm. From this fact, the necessary plate thickness for the specimen is 50 mm to determine the welding condition for the first pass of very thick plates.
    (5) For the slit specimen (B/l=1.875, L/l=2.5), the plastic restraint strains increase with an increase of the effective average restraint intensity (Rp)η, and their increasing tendencies are very similar (in Fig. 6). Therefore, (Rp)η may be used as a simple dynamical measure to compare the severity of the dynamical condition in place of the restraint strain.
  • 龍味 哲夫, 古藤 正男, 小松 博道, 安達 二朗
    Experimental Animals
    1990年 39 巻 3 号 361-369
    発行日: 1990/07/01
    公開日: 2010/08/25
    ジャーナル フリー
    アカゲザルをモンキーチェアに反復
    拘束
    する過程で各種生理値がどのように変化するかを観察し, モンキーチェア
    拘束
    に対する馴化過程について検討した。その結果, 心拍数, 血圧は
    拘束
    当初有意に増加したが,
    拘束開始後の時間経過ならびに反復拘束
    に伴って漸次減少した。そして, 1日当り8時間の
    拘束
    を5日間繰り返し, その後9日間通常ケージ内で飼育し, 次いで再び, 前と同じ
    拘束
    条件を負荷したところ, 最終的にモンキーチェア
    拘束下にもかかわらず無拘束
    条件下とほとんど変わらない値を示すようになった。血漿コルチゾール, CK, GOT値についてもほぼ同様の成績が得られた。これら
    拘束
    当初の生理値の上昇は, 交感神経緊張状態と
    拘束
    から逃れようとする全身運動が反映された結果とみられる。また, 反復
    拘束
    により生理値が正常域に復したことから, 今回設定した反復
    拘束
    条件はアカゲザルをモンキーチェアに馴化させるのに有効であると判断された。
  • 金 裕哲
    溶接学会誌
    2013年 82 巻 6 号 456-460
    発行日: 2013年
    公開日: 2015/04/09
    ジャーナル フリー
  • 渡辺 正紀, 佐藤 邦彦
    溶接学会誌
    1964年 33 巻 7 号 513-523
    発行日: 1964/07/25
    公開日: 2011/08/05
    ジャーナル フリー
    It is well known that reaction stresses of weldments produced during cooling under external restraint will be one of the serious factors affecting on weld cracking particularly on cold cracking. That is the reason why various types of restrained specimen have been used for weld cracking test. Reaction stresses in these specimens will be changed by the two factors ; the one is the relative rigidity of weld metal to restrained specimen and another is free contraction due to welding. Weld cracking test results may be influenced by the rigidity of specimen used even if the same conditions of materials and heat input are used. Therefore, it will be important for the evaluation of weld cracking test results to obtain informations on the rigidity of cracking test specimens.
    In order to consider the rigidity of restrained specimens, restraint coefficient was used, the definition of which is such that the restraint coefficient is equal to average value of transverse stress along weld line necessary to produce average elastic change of root gap of unit magnitude along the weld line. The restraint coefficient thus defined will be calculated with elastic theory for restrained specimens of simple shape, however, the calculation will be difficult for more complicated specimens and practical welded joints. For the measurements of restraint coefficient a new apparatus called "Restraint Meter" was designed by the authors. Principle of the restraint meter is that separating force is applied to both beveled edge planes of a weld groove before welding by the action of a wedge pushed into the groove and then the change of root gap is measured with displacement gauges. The separating force per unit change of root gap will be increased with the increase of rigidity. The restraint coefficient can be obtained from the separating force.
    Measurement of restraint coefficient by the restraint meter was performed for various cracking test specimens such as Lehigh type, N.R.L. type and Tekken type, which is widely used in Japan. Restraint coefficient of Lehigh type specimens ranges between 33 and 75 Kg/mm2. mm for 75 mm weld length and 11 and 45 Kg/mm2. mm for 125 mm weld length. Tekken weld cracking specimen shows 59 Kg/mm2. mm restraint coefficient. Reftraint coefficient of N.R.L. type specimen is much smaller than the above two because a end of weld groove is opened. (See Column (4) in Table 1.)
    The restraint coefficient obtained has close relationship to reaction force due to welding by the equation
    R=phlΔl
    where R: reaction force due to welding
    p: restraint coefficient
    h: thickness of plate
    l: weld length
    Δl: average elastic dislocation along weld line
    The relationship was confirmed for Lehigh cracking test specimens as shown in Table 2. (See Columns (5) and (8) in Table 2.)
  • 迎 静雄, 寺崎 俊夫, 小南 鮮寿, 石本 憲司
    溶接学会論文集
    1983年 1 巻 1 号 57-63
    発行日: 1983/05/05
    公開日: 2009/06/12
    ジャーナル フリー
    The JIS-y root cracking specimen and H-slit restraint cracking specimen have been widely used in Japan in investigating cold cracking of steel weldments. While the former is small but possesses constant restraint, the latter is large and expensive.
    In this report, the Controlled Restraint type Slit cracking specimen (CRS specimen) with slits at both edges of test welding line of JIS specimen is proposed, and the cold cracking tests are conducted after investigation of relation between slit length, restraint intensity, and stress. When these test data are arranged using restraint stress and residual diffusible hydrogen content of weld metal, a distinct line is found as the critical curve for cold cracking. Moreover the results are applied to actual weld procedures.
  • 桐原 誠信, 小沼 勉, 渡辺 潔
    溶接学会誌
    1977年 46 巻 7 号 437-443
    発行日: 1977/07/05
    公開日: 2011/08/05
    ジャーナル フリー
    With the demand for the increasingly large capacity of machines and equipment, structural dimensions are growing large, and design stress is becoming higher eventually. This naturally necessitates the use of high-strength steel possessing high tensile strength and high toughness.
    Although mild steel is generally adopted for welded structures, it needs an exceedingly large gauge to give sufficient strength and involves difficulites in builiding up welded structures. In this report an examination was conducted on the effects of intensity of restraint, restraint stress, and the groove shape influencing delayed cracks during manual are welding on high-strength steel.
  • 上田 幸雄, 福田 敬二, 金 裕哲
    溶接学会誌
    1983年 52 巻 2 号 104-109
    発行日: 1983/02/05
    公開日: 2011/08/05
    ジャーナル フリー
    In this paper, a series of elastic analysis was conducted on the restraint intensity of a rectangular plate with a slit, changing only the plate thickness (keeping the throat thickness constant) and the distance from the center of plate thickness to that of throat thickness. Two -types of loading conditions were used for the above analysis, which were (1) application of uniformly distributed loads along the slit and (2) imposition of uniform displacement, instead.
    The main results are as follows.
    1) If the ratio of the plate thickness to the throat thickness, h/hw is approximately smaller than 3.5, it may be considered that the plate thickness is entirely effective regardless of the type of groove. On the other hand, if the ratio is greater than the above (for thicker plate thickness), the restraint intensity is not in a simple proportion to its plate thickness, and converges to a certain limit. An expression of the correction factor r/ for the effectiveness of plate thickness is proposed.
    2) If the first weld is laid deviated from the center of the plate thickness, the out-of-plane bending deformation is produced according to the magnitude of the eccentricity and the effective restraint intensity at the center of the plate thickness decreases. However, within the range of eccentricity e=h'/(h/2)= 2h'/h<0.4 (h' is the distance from the center of plate thickness to that of throat thickness), the influence of the eccentricity can be neglected. An expression of the correction factor η' for the effect of eccentricity is formulated.
    3) If the one side angle of the practical groove is within 45 degrees, the influence of the groove form can be disregarded.
    4) As very accurate correction factors η and η' were obtained, the effective restraint intensity in a slit weld joint of a finite rectangular thick plate can be calculated simply by multiplying these correction factors to the two dimensional restraint intensity on which the thickness of the base plate is entirely effective. Consequently, the effective restraint intensity can be obtained simply without performing three dimensional elastic analysis which requires a huge amount of computing time.
  • 佐藤 邦彦, 松井 繁朋, 西村 岩夫, 飯山 英明, 千葉 尚道, 長谷部 茂雄, 別所 清
    溶接学会誌
    1976年 45 巻 11 号 952-960
    発行日: 1976/11/05
    公開日: 2011/08/05
    ジャーナル フリー
    Weld cracking is one of the most important problems in constructing steel structures. It has been investigated to estimate the occurrence of weld cracking by use of the factor such as the intensity of tensile restraint. However, weld cracking is sometimes caused by the angular distortion particularly in multipass weld.
    The intensity of bending restraint is proposed as the parameter which evaluates quantitavely the restraint of the angular distortion. In this paper, the effect of the intensity of bending restraint on weld cracking in multipass weld is investigated by use of a newly developed small size test called "Bending Restraint Weld Cracking test (BRC-test)". The occurrence of weld cracking in actual structures is similar to that in the BRC-test. Therefore, the occurrence of weld cracking in actual structures can be predicted by use of the intensity of bending restraint of the structures based on the results of the BRC-test.
  • 渡辺 正紀, 佐藤 邦彦, 松井 繁朋
    造船協會論文集
    1963年 1963 巻 113 号 136-145
    発行日: 1963年
    公開日: 2009/01/08
    ジャーナル フリー
    On weld cracking, especially on the cold cracking during cooling, intensity of restraint of weld joint is one of the important factors. Research was attempted to investigate the behavior of weld cracking under some restraining conditions and to obtain informations on the effect of reaction stress on weld cracking. A new test apparatus as shown in Fig. 1 was used for direct measurements of reaction stresses during cooling. Both forced and restraining tension tests were made by the apparatus. The former is such that a specimen is fractured by tensile load at a high temperature during cooling, and the latter is such that the length of a specimen is kept constant during cooling.
    Experiments were carried out on both weldments of a mild steel and a high strength steel of 60 kg/mm2 tensile strength level.
    High strength steel weldments have higher fracture stress and elongation than those of mild steel weldments in forced tension tests during cooling. In restraining tension test, however, reaction load increases gradually with cooling, and higher intensity of restraint usually favours crack initiation and decreases the time required for cracking. At first, micro crack occurs at root of weld, after which it intermittently develops with cooling. In higher intensity of restraint, it develops to complete fracture before the weldment is cooled to room temperature. In most of the specimens, however, the development of the micro crack stops without complete fracture and constant reaction load is kept at room temperature. After such specimens were kept at the constant reaction loads for 2 or 3 days, no more development of the micro cracks was observed. Micro crack initiation occurs at a lower reaction stress as compared with fracture stress obtained by forced tension test, and the larger difference between them is observed for high strength steel weldments.
  • 里中 忍, 立川 逸郎
    溶接学会論文集
    1986年 4 巻 2 号 417-423
    発行日: 1986/05/05
    公開日: 2009/06/12
    ジャーナル フリー
    The present study examines the mechanism of bending distortion during multi-layer welding of restrained butt joint in aluminium heavy plate. The experiments were performed to observe the reaction force, bending moment, deflection of plate and strain distribution during or after welding. Moreover, a theoretical consideration based on the theory of plates was applied to these results and effects of factor on the bending distortion were discussed. The main results are as follows.
    The transient deflection during the welding of each pass changes according to the bending moment roughly in a such way that the deflection mode is concave at weld side during heating cycle and convex during cooling cycle. The bending distortion depends upon the reaction force, its eccentricity from the neutral plane of base plate and the plastic deformation. The effects of reaction force and of its eccentricity are remarkable for the first passes and the effect of plastic deformation unevenly distributed in the thickness direction appears for later passes. The bending deflection of plate decreases as the throat thickness increases and as the restrained length decreases. The plastic strain results from the restraint of thermal expansion of plate and from the bending deflection during welding, and its distribution is nearly linear from top face to bottom face. By applying the theory of plate to these specimens, the bending moment and inherent angular deformation of throat are calculated from the measured value of the reaction force, its eccentricity and bending moment of the welded plate, and the effects of eccentricity and inherent angular deformation upon the bending moment of the throat are predicted.
  • 桐原 誠信, 小沼 勉, 渡辺 潔
    溶接学会誌
    1977年 46 巻 2 号 89-95
    発行日: 1977/02/05
    公開日: 2011/08/05
    ジャーナル フリー
    The relationships between various weld crack test methods were discussed at the 9th Commission meeting of I.I.W. This article evaluates crack determination methods for slit groove tests, H-type restraint cracking tests, TRC tests, RRC tests and Implant tests, and discusses the intensity of restraint and restraint stress influencing crack prevention preheating temperatures. Finally the relationships between various test methods are clarified concerning cracks caused in first layer. The results are as follows:
    (1) The dependence of delayed cracks on colling speed (preheating), intensity of restraint, restraint stress and stress concentration will be explained using 80 kg/mm2 high-strength steel.
    (2) A nomograph was made up to clarify the relationships between the various test methods by relating the crack prevention preheating temperatures to critical restraint stress and critical intensity of stress in the first layer of 80kg/mm2 high-strength steel.
  • 明石 重雄, 夏目 光尋
    溶接学会誌
    1974年 43 巻 6 号 611-618
    発行日: 1974/06/25
    公開日: 2011/08/05
    ジャーナル フリー
    It has been recognized empirically by engineers that the angular distortion on welded joint, which is caused by the eccentric shrinkage of deposited metal, is somewhat related with weld cracking.
    The purpose of this work is to evaluate quantitatively the resistance force against angular distortion, naming it as "Bending Restraint Intensity", and also to clear experimentally the role of bending restraint in the cracking behavior.
    The definition of Bending Restraint Intensity is given as "Bending moment intensity per unit weld length required to cause unit angular distortion at joint, KB=M/θ, kg.mm/mm. rad".
    Bending Restraint Intensity possessed in self-restraint specimens now being used for cracking tests is to be calculated by finite element method. For the joints with no self-restraint a loading apparatus was devised to give optional KB.
    The weld cracking tests were made on these restrained joints of different types; one was one pass welds with bending and tensile restraint, one was multipass weld with bending restraint, and the other was partially penetrated multipass weld with bending restraint.
    Included in this paper is description on the property of bending restraint, the testing apparatus, results of cracking tests with given Bending Restraint Intensity, and a summary and interpretation of the results.
  • 佐藤 邦彦
    溶接学会誌
    1964年 33 巻 6 号 439-445
    発行日: 1964/06/25
    公開日: 2011/08/05
    ジャーナル フリー
    Weld cracking is influenced by both reaction stress during cooling and properties of weld metal and heat-affected zone. The problems of weld cracking, therefore, should be explored not only from metallurgical standpoint but also from standpoint of reaction stress. Researches on effect of reaction stresss during cooling or restraint on weld cracking are now undertaken by the authors, especially for first-pass-weld-cracking of restrained welds of some mild and high strength steels. At earlier stage of the research project, informations on what factors influence to reaction stress under restraint were wanted for reasonable research planning. The present paper was prepared as preliminary informations for the subsequent test planning.
    In a restrainning system shown in Fig. 1 shrinkage force will be produced by hindered contraction or extension of first-pass weld metal during cooling. Analytical investigation was conducted on the extension of weld metal. The anaiysis is based on the assumptions that behavior of mother plate (B) and restraining members (C) is elastic during cooling, however, in the weld metal will be produced some plastic deformations under the stress-strain relation as shown in Fig. 3. The extension (λw) of weld metal at a given temperature below about 300°C is obtained by
    pwhw/ph⋅λwnw=S
    where ph and pwhw are rigidity or force per unit weld length required for unit extension of mother plates and weld metal respectively, and S is free contraction between restrained length (l) of mother plate. Relations of λw versus rigidity ratio pwhw/ph are shown in Fig. 4 for a few values of S. Larger extension of weld metal will be produced under smaller rigidity ratio and larger free contraction.
    Free contraction S will be influenced by heat input and overall cooling behavior of mother plate of length l. Under a given heat input the overall cooling rate or heat loss from the mother plate of length l will be increased as the decrease of heat capacity or length (l) and thickness (h) of mother plate.
    It will be concluded, therefore, that under a given heat input reaction stress of weld metal at a given temperature is influenced by the following factors ;
    1) restraint coefficient (p), which contains restrained length (l) and ratio of sectional area of mother plate to restraining members.
    2) thickness (h) of the mother plate.
    3) restrained length (l) of the mother plate.
    4) rigidity of weld metal (pwhw).
    Figs. 8 and 9 show some calculated examples of the effect of l and h on the extension of weld metal.
  • 上田 幸雄, 福田 敬二, 金 裕哲, 古木 良一
    溶接学会誌
    1982年 51 巻 8 号 636-643
    発行日: 1982/08/05
    公開日: 2011/08/05
    ジャーナル フリー
    The mechanism of the cold weld cracking may be simply stated from the mechanical aspect that the cold crack initiates when the stress and strain induced at a point reach the critical values. In this respect, the stress and strain are the important information to prevent initiation of cold cracking from the dynamical point of view. In connection to this, a series of researches is carried out on this kind of problems. A slit weld in a rectangular plate is chosen as the basic research model because of its two dimensional restraint state in which the constraint of thermal expansion and shrinkage varies along the weld line.
    In this paper, experiments are conducted in order to investigate the validity of the already proposed analytical calculation method for the inherent shrinkage which is the direct factor of producing restraint stresses and strains in the perpendicular direction to the weld line and for thus produced restraint stresses and strains. From the result, the characteristics of the restraint stress and strain produced in the weld metal are clarified. At the same time, the restraint strain which can be estimated by a simple calculation is proposed as a more general dynamical measure for initiation of cold cracking. In addition, the restraint intensities under three loading conditions are investigated of their significance as a dynamical factor in case of estimating the restraint stress and strain.
  • 立川 逸郎, 岡本 龍正
    溶接学会誌
    1978年 47 巻 1 号 31-36
    発行日: 1978/01/05
    公開日: 2011/08/05
    ジャーナル フリー
    In the present paper, the behaviours of restraint force and bending moment and distortion in three-pass welding of medium thick (12.7 mm) HT80 steel plate are investigated experimentally using H-type restrained specimens. The main results are as follows:
    According as the thermal contraction of weld occurs after welding the first pass, restraint tensile force and bending moment that bends the restraint plates convex upward grow due to nonelastic shrinkage caused in the weld zone and its downward eccentricity about the neutral plane of base plate, though their signs as well as magitudes are changed temporarily when the transformation of austenite accompanying expansion takes place in the weld zone.
    In each welding of the second and third passes, the initial distortion and restraint force are almost extinguished by the heating, and in the cooling processes the restraint force and bending moment are reproduced in accordance with the magnitude and eccentricity of the shrinkage and expansion.
    The amount of transverse inherent shrinkage in the weld zone after welding each pass is approximated by subtracting the expansion mostly referable to the phase transformation from the calculated value of plastic contraction induced by constraining the thermal expansion of weld.
    The experimental values of intensity of tensile restraint for the weld-joints are scarcely affected by their angular distortions.
  • *山元 佐和子, 古川 順光, 竹井 仁, 金子 誠喜
    理学療法学Supplement
    2007年 2006 巻 1256
    発行日: 2007年
    公開日: 2007/05/09
    会議録・要旨集 フリー
    【目的】
    円背による胸郭変形は
    拘束
    性換気障害をもたらし高齢者のADL低下の重要因子と推定されている.理学療法の対象のなかには車椅子生活をしている者もいるが,円背や
    拘束
    性換気障害による呼吸循環応答の変化について車椅子駆動時の検討を行った研究は少ない.今回,胸郭の運動を制限し車椅子駆動時の呼吸循環応答を知ることを目的に実験を行った.なお本研究は首都大学東京健康福祉学部研究倫理委員会にて承認を受けた.
    【対象】
    対象は研究について説明し同意を得た整形疾患および心肺機能の既往がない健常成人11名(男性6名,女性5名)で,平均の年齢21.6歳,身長168.8cm,体重61.9kgであった.
    【方法】
    胸郭運動制限は弾性腰椎コルセットにて腋窩-剣状突起間の運動を抑制することで得た.利き手側片手片足にて快適速度で直線200mの車椅子駆動を行った.胸郭運動制限の有無により非
    拘束
    拘束
    の2条件で剣状突起レベルの胸郭拡張差を測定,スパイロメトリ(HI-201,ミナト医科学)で安静時肺活量(SVC),%肺活量(%VC),努力肺活量(FVC),一秒量(FEV1.0),一秒率(FEV1.0%)を測定した.携帯型呼気ガス分析装置(K4b2,COSMED)で安静・駆動時の心拍数(HR),酸素摂取量(V(dot)O2),分時換気量(V(dot)E),一回換気量(TV),呼吸数(Rf)を測定,速度[m/min],代謝当量(METs),酸素負債を算出した.統計解析はSPSS(ver.10)で制限の有無を因子とした対応のあるt検定を実施,有意水準5%未満とした.
    【結果】
    肺機能検査の平均値は胸郭拡張差7.5cmに対し
    拘束
    3.6cm,SVC4.3lに対し
    拘束
    2.7l,%VC111.6%に対し
    拘束
    70.9%,FEV1.0%88.4%に対し
    拘束
    87.2%であった.胸郭拡張差,SVC,%VC,FVC,FEV1.0は,非
    拘束に比べ拘束
    で有意に低かった.安静時呼気ガス分析はTV0.6lに対し
    拘束
    0.5l,Rf15.8回/minに対し
    拘束
    19.8回/minであった.また駆動時TV1.1lに対し
    拘束
    0.8l,Rf18.2回/minに対し
    拘束
    27.9回/minで,安静・駆動時ともRfは非
    拘束に比べ拘束
    で有意に増加していた.HR,V(dot)O2,METs,速度に有意差はなかった.酸素負債は364.7ml/minに対し
    拘束
    488.4ml/minで有意差を認めた.
    【考察】
    拘束
    では,安静時のTV減少とRf増大が認められたことから,Rfが増大することでTV低下を代償したと考えられる.酸素は
    拘束
    ・非
    拘束
    によらず同程度摂取されているが,酸素負債は
    拘束
    で増大した.酸素負債は運動中の酸素不足を反映しているとされ,今回METs,速度に差がないにもかかわらず安静・駆動時のRfが増大していることから,駆動中の酸素不足は呼吸筋の酸素消費量増大によるものと考えられる.以上より,胸郭運動制限下での車椅子駆動は,低コンプライアンスによる換気量低下に対する代償のため呼吸筋の酸素消費量が増大することから,呼吸筋や胸郭のコンディショニングを含めた運動処方を行うべきである.
  • 大型油槽船のブロック継手の拘束に関する検討
    武藤 昌太郎, 栗田 剛利, 栗原 幸雄
    造船協會論文集
    1962年 1962 巻 111 号 263-272
    発行日: 1962年
    公開日: 2009/01/08
    ジャーナル フリー
    In Report No. 3, we showed that there was no remarkable difference between the reaction stress in way of master butt, which concerns with residual stress and intensity of restraint, and reaction stress in common butt, from the actual ship experiment on oil tanker “Andros Tanker”, 41, 000 D. W. This result seems to be unnatural, because it is considered that the condition of restraint to common block butt and master butt are obviously different. To solve this problem, further experiment was carried out on the other ship of 73, 000 D. W. oil tanker.
    First, the mechanical force was applied to upper deck block twice, firstly as erected and lastly before welding, in order to observe the block behaviour. This experiment was conducted to find the fundamental relationship between the displacement of block and the external force. Next, we compared thus obtained actual result with a presumed curve which can be drawn by considering the ideal case in which there exist no other than block friction.
    Through the above experiment, in actual ship, it is found as follows :
    (1) The outer force which is sufficient to keep the newly erected block moving increases slowly until the block butts contact, and after rapidly. It should be pointed out, however, that the displacement of block is taken place by considerably smaller force than that expected in consideration of elastic deformation of block. It is considered that this fact is due to the dislocation or destruction of root face at the block butt.
    (2) Comparing the displacement of block at common block butt with at master butt, rigid block motion takes place at the former, while it does not at the latter.
    (3) The difference of reaction stress between common block butt and master butt is less than 2 kg/mm2 which agrees with the result in Report No. 3. It follows from the above that it is not the rigid body motion of block that govern the residual stress, but the degree of the self-restraint of weld in connection with thermal effected zone.
    (4) Thus, it is concluded that master butt under the Method of Erection Started Simultaneously at Several Locations, as is used in this ship yard may be treated quite in the same way as in the case of common block butt, provided that master butt weld properly carried out, for example adopting the method of simultaneous weld by many welders.
  • 立川 逸郎, 里中 忍, 向田 慎一
    溶接学会論文集
    1984年 2 巻 4 号 707-713
    発行日: 1984/11/05
    公開日: 2009/06/12
    ジャーナル フリー
    In this paper, the mechanisms of restraint force and bending moment as well as transverse distortions in multi-pass TIG welding of aluminum alloy are experimentally studied using H-type restrained V-groove joints, and the discussions emphasize plastic deformation in the weld. The main results are as follows.
    1) Cooling effect of the shield gas causes a sharp drop in peak temperature of weld thermal cycle at top surface layer of the weld zone and consequently temporary fluctuation of the transient bending moment.
    2) The basic mechanisms of restraint stress and distortions in the weld are generally the same as in welding thick steel plate.
    3) In welding each pass, the transverse shrinkage by plastic deformation grows up at vicinity of the weld metal under restraint compressive stress during heating process, and then decreases by elongation under restraint tensile stress during cooling process with a consequent shrinkage at room temperature. The tensile plastic strain occurs in a wide area of the base plate as well as the weld zone, and the transient tensile stress at boundary of the area reaches the value of yield stress of the base metal at a temperature during cooling process. Both magnitude of the plastic strain and extent of the plastic zone increase with increasing built-up passes.
  • 渡辺 正紀, 佐藤 邦彦, 松井 繁朋
    溶接学会誌
    1964年 33 巻 6 号 446-457
    発行日: 1964/06/25
    公開日: 2011/08/05
    ジャーナル フリー
    Control of weld cracking is one of the most important problems for welding engineers. Weld cracking is influenced by welding stress during cooling as well as properties of weld metal and heat affected zone. The problems of weld cracking, therefore, should be explored not only from metallurgical strandpoint but also from standpoint of welding stress. In this report research was focused on the influence of restraint on weld cracking.
    A new test apparatus as shown in Figs. 3 and 4 was designed for evaluation of sensitivity for root cracking of steel welds. With this apparatus, "Rigid Restraint Weld Cracking test (RRC test)" as shown in Fig. 1 was developed, it is such that the length of a specimen is kept constant during cooling. The RRC test method is similar to the TRC test developed by Dr. Suzuki and his collaborators for the researches on root cracking of high strength steel welds. However the authors' test method differs from the TRC test as follows : In the TRC test a constant load was applied at a few minutes or immediately after welding because emphasis was laid on only delayed root cracking of high strength steel welds. The authors' test method is very significant, on the other hand, for the two reasons which (1) it gives gradual increase of reaction load by keeping the length of a specimen always constant during welding and cooling and also (2) it permits a wide degree for adjustability in the restraint intensity by changing the gauge length of restraining (l), (See Fig. 1). This may be much similar to the actual behavior of restrained welds and will be reasonable as the test method for weld cracking under restraint during cooling as well as after cooled to room temperature.
    Experiments were carried out on the weldments of a mild steel and high strength steels of 60 and 80 kg/mm2 tensile strength level.
    The results obtained are as follows.
    (1) In the RRC test, shinkage rate and magnitude of reaction stress were widely changed with changing the gauge length of restraining, and weld crack occurs in wide range of temperature. Reaction load increases gradully with cooling, and higher intensity of restraint usually favours crack initiation or decreases the time required for cracking.
    (2) In mild steel weldments, weld crack occurs only during cooling and no crack initiation is observed after cooled to room temperature.
    (3) In high strength steel weldments, on the other hand, crack initiation was observed not only during cooling but also after cooled to room temperature.
    (4) This delayed cracking was observed even at lower reaction stress level. Minimum reaction stress level for the delayed cracking is 33 kg/mm2 for HT-80 steel and 60 kg/mm2 for HT-60 steel. The incubation period was measured 1-10 hours for HT-80 steel and 20 hours for HT-60 steel after welding.
    (5) Critical gauge length (lcr) of restraing, over which no crack initiation was observed, was 300-370 mm for mild steel, 450-500 mm for HT-60 steel and 550-600 mm for HT-80 steel.
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