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21 巻, 221 号
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奥島 正一1972 年 21 巻 221 号 p. 67-75
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーPDF形式でダウンロード (1141K) -
網島 貞男, 石田 喜昭, 松見 政彦1972 年 21 巻 221 号 p. 76-82
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーRecently we have seen many experimental data published on the static properties of the glass fabric reinforced plastics (F. R. P.), but there have been few reports so far which have treated the influence of environmental temperature and the glass content of the specimen.
It is intended in this paper to describe (the influence) of the glass content and the environmental temperature on the static behaviour of F. R. P. in which satin woven, plane woven and roving woven fablics are used for reinforcement. On the other hand we made analysis to predict the elastic moduli in flexure of composite laminates and determined their flexure strength by the use of these calculated moduli with the assumption that the F. R. P. materials will keep their elastic properties till the moment of fracture.抄録全体を表示PDF形式でダウンロード (890K) -
平 修二, 後藤 徹, 黒部 利次, 葛西 靖正1972 年 21 巻 221 号 p. 83-89
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーThe stress-strain behavior of annealed low carbon steel under cyclic straining was investigated, and the results obtained are as follows.
(1) Under cyclic straining of constant total strain ranges of 2, 3 and 4%, the stress range increased with the increase in cyclic number. On the other hand, it decreased when the mean strain of 10% was applied. However, the stress range had a tendency to saturate with increase of cycles in both cases.
(2) The stress σ'-plastic strain εp' relation in half cycle with the reference point at the tip of hysteresis loop was found to be composed of two linear portions on log-log plotting. The relation was described in the form of
σ'=K'{2εpoα1-α2-2/πtan-1(εp'-εpo'/a)+εpo'α1-α2/2}εp'{α1-α2/πtan-1(εp'-εpo'/p')+α2α1}/2
where α1 and α2 are the strain, hardening exponents according to the relation of plastic strain in value whether large or small respectively. εpo' is the plastic strain dividing the plastic strain in the semi-cycle into two portions.
(3) Strain range and the number of cycles seem to have little effect on the values of α1, α2 and εpo'. α1 and α2 were about 0.18 and 0.08, respectively, and the former was about twice as large as the latter. εpo' was in 0.6-0.9%. The mean strain produced larger value of α2 in the semi-cycle of straining reverse to the mean strain in its direction.
(4) The two different strain hardening exponents found in the semi-cycle may indicate that the elasto-plastic deformation occurs before plastic deformation during the semi-cycle.
(5) In the saturated hysteresis-loop shape of stress-strain at various strain range, the stress range and plastic strain range was related as follows;
Δσ=KoΔεpα0
with α0 of 0.19.抄録全体を表示PDF形式でダウンロード (1429K) -
南澤 力, 青木 望, 芳賀 武, 石田 有示1972 年 21 巻 221 号 p. 90-96
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーUsing the values of deflections which can be measured easily during the rotatory bending fatigue test of a specimen, and considering also the stress distribution on the cross section of the specimen, the authors have devised a method to analize quantatively the plastic and quasi-elastic strain energies per cycle and their accumulation.
In this paper a report is made of the devised method as applied to fatigue tests of two kinds of carbon steels including different pearlite patches.
The main results obtained from the research are as follows:
(1) The pearlite patch not only causes structural changes by fatigue but prevents propagation of cracks.
(2) The change in quasi-elastic energy accumulation with the fatigue process can be expressed in Σqq=1(IRRAD.E)q=AqK up to the occurrence of micro-cracks on the surface of the steel specimen including gross patches and fracture of the specimen including fine patches.
(3) If the plastic strain energy accumulation is plotted against the number of cycles on a log-log paper, four nodal points appear dividing the process of fatigue in five stages. The second nodal point in the initial fatigue appears to have relation with the yield of materials. Then, a fine slip appears in the vicinity of second nodal point, a slip band at about third nodal point and a intrusion at about fourth nodal point. The energy quantities at the third and the fourth points were a constant to the respective point, independent of the stress amplitudes and of the pearlite patches. The energy quantity required for the fracture of specimen was a constant to each stress amplitude.抄録全体を表示PDF形式でダウンロード (2044K) -
平 修二, 田中 啓介1972 年 21 巻 221 号 p. 97-103
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーNotched specimens of annealed 0.03%C steel were fatigued under completely reversed in-plane bending. The topography on the fatigue fractured surface was examined by electron and optical microscopys, and the change in topography with the crack propagation rate was investigated. The range of the propagation rate obtained in this study was 10-8∼5×10-3mm/cycle. The results are summarized as follows:
(1) The three features, the facets of grain boundary fracture, the imbricate pattern and the parallel pattern, were observed on the fractured surface when the propagation rate was lower than 10-5mm/cycle.
(2) Striations were observed on the surface fractured with the rate higher than 2×10-5mm/cycle. The spacing between striations was equal to the propagation rate within the range of 10-4∼2×10-3mm/cycle. The spacing was larger than the rate at dl/dN=2×10-5∼10-4mm/cycle, while it was smaller at dl/dN>2×10-3mm/cycle.
(3) Cleavage facets were observed on the fractured surface when the propagation rate was higher than 3×10-4mm/cycle. The summed area of cleavage facets on the fractured surface increased with the propagation rate to about 10% of the total area of the fractured surface at dl/dN=5×10-3mm/cycle.
(4) The tip profile of fatigue cracks that ran within the specimen in accordance with its thickness bent in convexwise in the direction of growth when the propagation rate was higher, while it bent in concavewise when the rate was lower. The change in the tip profile was explained by the difference in growth mechanism with the propagation rate.抄録全体を表示PDF形式でダウンロード (2995K) -
岸本 秀弘, 小倉 興一, 粟津 重男1972 年 21 巻 221 号 p. 104-108
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーHereunder is given a report of investigation made of the effect of cast skin and shot peening on the plane bending fatigue strength of annealed and normalized spheroidal graphite cast iron produced by addition of Si. The results obtained are as follows.
(1) The fatigue strength reduction factor due to the cast skin, in the case of annealed iron, is 118. This reduction is attributed mainly to the surface roughness (Hmax=50S) and the decrease of solute Si content in α-Fe of cast skin.
(2) The fatigue limit in normalized iron with cast skin drops to 74% as high as the iron without cast skin. The main factors for this decrease are decaburization, small pits, and the decrease of solute Si content in α-Fe of cast skin. The fatigue strength reduction factor due to the above mentioned two last causes is about 1.17.
(3) Graphite of irregular form is seen near the bottom surface, but the irregularity does not affect the fatigue strength.
(4) The cast skin is strengthened so much by shot peening that subsurface failure occurs in every shot peened specimen.抄録全体を表示PDF形式でダウンロード (1572K) -
大南 正瑛, 塩沢 和章, 神谷 章1972 年 21 巻 221 号 p. 109-116
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーIt is intended in the present paper, as one of the series of study on the influence of hydrostatic pressure on the mechanical behavior of polycrystalline metals, to investigate the influence of hydrostatic pressure soaking on the structural change of deformed metals, using the Laue method of X-ray back reflection. From the present study it had been elucidated that the use of the Laue method of X-ray back reflection had proved fruitful experiment, though it is misorientation, for the study on the influence of the hydrostatic pressure on plastic deformation of metals, showing not only the density in edge and screw dislocation but also the vacancy and presence of interstitial atoms in the deformed metals. From the present analytical and experimental studies on pressure soaking of 2000kg/cm2 for coarse-grained sheet specimen of aluminum pulled at atmospheric pressure, the following conclusions have been made:
(1) As the result of measurement of dislocation density, no change in dislocation density which is represented by torsion tensor has been observed immediately after the pressure soaking.
(2) The density of imperfection which is represented in Riemann-Christoffel curvature tensor has remarkably changed immediately after the pressure soaking. It is considered therefore that the arrangement of dislocation and the density of vacancy are influenced by subjection of hydrostatic pressure to the sheet of polycrystalline metals.
(3) The structural recovery which has been examined by the decrease in both density of dislocation and imperfection is observable in the elapse of 24 hours after the pressure soaking.抄録全体を表示PDF形式でダウンロード (1095K) -
野口 徹1972 年 21 巻 221 号 p. 117-122
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーSintered steel contains numerous residual pores, and shows some characteristics of mechanical behavior different from those of ordinary metallic materials. Specimens of sintered steel with carbon content of 0.7%, and two different densities, 6.2g/cc and 6.7g/cc respectively, were examined with respect to their elastic moduli.
The results obtained are summarized as follows;
(1) The specimens showed a clear yield point and in the stress above the yield stress the elastic modulus decreased with increasing stress.
In tension, the elastic moduli decreased to 80∼90% of original value just before failing in both specimens.
(2) To explain the mechanism of the decrease of elastic moduli, the present author proposed a new element of mechanical model named the“breaker”. The breaker acts as a rigid body until the stress reaches a certain point, where it breaks off and after that point, it can not support any load.
(3) By assuming a mechanical model in which the breaker elements of various strengths are distributed and break off continuously with increasing stress, the elastic moduli VS stress relation of sintered steel can be described.
(4) In the actual fracture process of sintered steel, the breaking of the breaker element seems to correspond with the initiation and propagation of microscopic cracks and local failures in the vicinity of residual pores.抄録全体を表示PDF形式でダウンロード (1860K) -
佐々 宏一, 伊藤 一郎1972 年 21 巻 221 号 p. 123-129
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーThe dynamic stresses in the materials having various assumed properties caused by detonative loading are computed by using the numerical technique which involves the finite difference in approximation to the equation of motion in the Lagrangian coordinate system, and then, the patterns of the breakage around the explosion, and the behaviour of the stress waves projected into the materials are discussed by referring the results to the above mentioned stress analysis.
Concerning the pattern of the breakage around the spherical explosion, it is concluded that the yield zone or shear failure zone is produced in close proximity to an explosion, and this zone is surrounded by the tensile fracture zone consisting of the radial cracks. Finally, the patterns of the breakage of the mild steel and the plexiglass (PMMA) subjected by detonative loading are presented, and it is pointed out that these are explained fairly well by the results of the above mentioned numerical analysis.抄録全体を表示PDF形式でダウンロード (1474K) -
日根 文男, 保田 昌樹, 松井 富士夫1972 年 21 巻 221 号 p. 130-134
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーCorrosion of iron and steel in neutral solutions of potassium chloride has been studied with rotating ring specimens. Since the oxide film deposited on the metal surface is much affected by small change of conditions, the corrosion rate vary significantly. The ratio of the maximum corrosion rate to the minimum rate, or to the average rate, is considered to be the“Safety Factor” under general corrosion conditions. The ratio was once recorded to be 1.5-2.5 in aerated solutions of KCl at 50°C, and was almost independent of the carbon and copper contents, probably due to the short-range experiment for only 100 hours.
The physico-chemical properties of oxyhydroxide that precipitated in the solution containing ferrous and/or ferric chloride were studied, i.e., the pH titration was carried out with a great variety, and the precipitates were examined by X-ray diffraction. Oxidation of both ferrous ions and oxyhdroxide precipitate with oxygen dissolved seems to be a major factor for formation of oxide film on ferro-metals.抄録全体を表示PDF形式でダウンロード (651K) -
吉本 彰, 後藤 紘海, 荻野 正嗣1972 年 21 巻 221 号 p. 135-142
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーThe present report gives data on the fracturing time of cement mortar beam under sustained load.
It is well known that the density function of transition probability of fracture in glass and polycrystalline metals shows constant value regardless of t. That is, the relation between in P(t) and t is linear. Where P(t) denotes the probability that the fracture of specimens does not occurred until the time of t.
On the contrary, the data obtained from this investigation show that the density function of transition probability of fracture in cement mortar is not constant. That is, the relation between lnP(t) and t is not linear. It appears that the microcracks developed in cement paste under sustained load are responsible for the nonlinear relation.
In this report, the effects of preloading, humidity of the air and moisture in specimen on the fracturing time are also shown, The preloading delays the fracture of cement mortar. The moisture in the air or in specimen delays the fracture immediately after loading but promotes the fracture after a certain time. It seems that these phenomena are also caused by the microcracks developed in cement paste.抄録全体を表示PDF形式でダウンロード (1127K) -
鈴木 傑, 神谷 嘉夫, 鈴木 保良, 小林 種雄1972 年 21 巻 221 号 p. 143-147
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーThe viscosity of glass in the systems As-S, As-S-I and As-S-Tl was measured by the beam-bending method at the temperature from the transition point to the deformation point. The plots of the logarithm of the viscosity versus the reciprocal of the absolute temperature are shown in Fig. 3, 4 and 5. From Fig. 3, it is clear that the slopes are more gentle with increase of S content above As2S3 in the system As-S. But in the systems As-S-I and As-S-Tl, on the other hand, they become, as shown in Fig. 4 and 5, more steep with increase of I and Tl contents, respectively.
The isoviscosity temperature curves are shown in Fig. 6, 7 and 8. In the As-S glass the temperature required to make it isoviscous is lowered with increasing S content above As2S3 and also in the As-S-I glass it is rapidly lowered with I contents.
Considering the linear relation in Fig. 3, 4 and 5, for the viscous flow of glass, the apparent activation energy can be calculated by the following equation; ΔE=Rd(logη)/d(1/T)1, where R is the gas constant. The results are shown in Fig. 9 and 10. In the As-S system, the activation energy has its peak at As2S3 and decreases rapidly around As2S8. In the As-S-I and As-S-Tl glass it increases with I and Tl contents respectively.
The retarded elasticity appears remarkably in the transition region of the As-S glass and increases rapidly above As2S8. It has been recognized by Tsuchihashi et. al.6) that S8 rings begin to form in the glass when the S content is greater than that of As2S8-9.5. Therefore, from the above results we may suggest that the apparent activation energy for viscous flow decreases rapidly and the retarded elasticity increases with increase of S8 rings in the transition region.抄録全体を表示PDF形式でダウンロード (580K) -
木材と水 (第3報)鈴木 正治1972 年 21 巻 221 号 p. 148-155
発行日: 1972/02/15
公開日: 2009/06/03
ジャーナル フリーPDF形式でダウンロード (1216K) -
1972 年 21 巻 221 号 p. 156
発行日: 1972年
公開日: 2009/06/03
ジャーナル フリーPDF形式でダウンロード (135K)
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