In the study of contact of two surfaces, surface roughness is especially important. So first it is necessary to study how an initial roughness changes under the given conditions. And distribution constants of the profile in terms of an estimation of roughness are useful. We press two surfaces each other under the given conditions, study the process of change of roughness and obtain a transformation law from distribution of the pressed surface profile to that of the initial profile. Using the results, we consider about the contacting ratio, the gap between two contacting surfaces and the coefficients of changing roughness determined by combination of two materials of the surfaces, etc.

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This paper describes the specially-designed cutting test apparatus and some results obtained with it. Cutting test with general machine tools such as lathe, miller, etc. is usually apt to be accompanied by some unnecessary influences. Hence, an orthogonal cutting test apparatus, using a sliding-block, was designed in order to eliminate such unfavourable effects. The construction and use of this apparatus are dealt with in the first half and the test results for mild steel in the latter half.

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In case of hammer-forging, it has heretofore been said that the forging effect is greatly influenced by anvil weight and rigidity of supporting material (represented in the form of equivalent spring) or, in other words, anvil weight ratio (anvil weight over hammer head weight) and rigidity of spring. However, the writer has found that, in case of free forging, as far as anvil weight ratio is larger than a certain value which is far smaller than that having been said to be the limit, there exists little influence of anvil weight ratio and rigidity of spring on hammer-forging effect. Result of experiments conducted and theoretical explanation therefor are given here.

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In order to solve various problemes in relation to hammer forging equipment, it is essential to clarify impact stress in hammer forging. However, due to difficulty of making this sort of experiments, there have been few reports of experiments which give us practical figures. Making experiments with model hammers and steam hammers for actual use, the writer has measured by means of Braun tube oscillograph various values of impact force and various relative conditions which are necessary for theoretical design of mount and foundation of forging hammers. From the result of these measurements, practical conditions and figures have been obtained. The writer has also found that shape of the stress greatly varies with material of the article hammered, and that close attention must be paid to the method of measurement for experiments of this kind.

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In this paper, the effects of a semi-circular notch in a semi-infinite thin plate subjected to plain bending are investigated by the use of the Poisson-Kirchhoff theory of thin plates. The analysis is developed with the help of the complex variable method and the unknown coefficients included in the solution are determined by the method of perturbation. Numerical results are presented in the form of graphs. In order to clarify the effects of making a semi-circular notch, the distribution of bending couples and stress concentration factor k_b are calculated and presented in the form of graphs.

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In this paper, the shear-lag in a thin-walled cantilever pipe is discussed, utilizing the author's fundamental differential equation in a single displacement for a thin cylindrical shell. The results are compared with those obtained by the simple beam theory or modified beam theory. The deflection at the loaded side is very close to that estimated by the modified beam theory, while the configuration of the elastic line and the stress distribution near the fixed side are fairly different from those presumed by such a beam theory.

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The problem of solving the stress distribution in a rectangular plate subject to forces acting in its plane is treated in this study by the method of strain energy, thereby the double Fourier cosine series are used and the boundary conditions are considered as the constrained conditions in the calculus of variations. Numerical calculations are carried out for some examples in order to investigate the accuracy of this method.

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The effects of cycle frequency on the fatigue strength of carbon steels under simultaneous corrosion in tap water and saline are studied. The stress σ_c given under corrosion fatigue increases to σ_ck owing to the notch effect of corrosion pits. At a certain repetition number of N, σ_ck reaches the fatigue strength σ of the same repetition number in air and fractures by corrosion fatigue occur. And the condition of fracture is given by Eq. (5), under consideration that the corrosion effect k increases with time and σ is a function of N alone. Various experimental results are well explained by this criterion. This conception is further extended to the corrosion fatigue combining the static pre-corrosion and also changing cycle frequencies during runs. For the corrosion fatigue under varying stress amplitudes the cumulative damage criterion was found to be applicable. And so the strengths of corrosion fatigue under wide stress conditions may be known.

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The frequencies in vibration of rectangular plates with circular holes are studied. The method is due to Ritz and the displacement is expressed in terms of the products of bar-solutions which satisfy the boundary conditions of plate. The kinetic and potential energies are given in the cases of clamped-clamped, clamped-free and clamped-supported ends. Numerical calculations are carried out in the case of the plate of which all edges are fixed and with a hole in centre. Experimental data are also given in the above mentioned case in which the ratio of edge lengths is 1/2 and the agreement with calculations is good.

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This research concerns the investigation on the behaviour of the hammer in the scleroscope of type D before it is clamped with the ball clutch the effect of the changeable action of the clutch on the rebound of the hammer and the hardness values measured. Then we compared the hardness values indicated on the hardness dial of the scleroscope with the hardness values which were calculated with the height of rebound of the hammer measured by the optical method. We also discussed the relation between the height of rebound of the hammer and the shape of its diamond tip.

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The author analyzed 1-2, 3, 4, ……, 2n, 2n+1 pass heat exchangers dynamically. This paper Part 1 contains the exact analysis of two-pass heat exchangers which have one shell-pass and two tube-passes. The author obtained fundamental heat exchange equations. System parameters are combined and arranged in dimensionless forms, and for the typical combinations of these system parameters the transfer functions are obtained. The author found 3rd order characteristic equations governing the heat exchange processes. The equations have coefficients of complex number, and can be solved graphically and numerically. An example of frequency response is given and compared with simple parallel-and counterflow heat exchanger in equal flow conditions. The diagrams show the great difference between the response of this two-pass type and the response of ordinary parallel-and counterflow type, and even in the same two-pass type extraordinary differences are noticed between case P-C and C-P ; especially the input and output relations are important.

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In order to measure dynamic loads on gear teeth, a strain gauge apparatus and a dynamical gear testing machine have been made. The strains at the tooth flank, where a strain gauge is attached, are observed and dynamic loads are measured by comparing dynamic strains with static strains. Dynamic behaviors of mating gears are analysed as those of a vibration system which is constructed by the masses of the pinion and gear and the combined stiffness of the mating teeth. Here, the variations of combined stiffness of mating teeth, tooth errors and contact ratio etc. are analysed. The results of the analyses show that measured dynamic loads or measured dynamic stress cycles nearly coincide with calculated results respectively.

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A series of experiments on the discharge and scavenging phenomena of two-cycle diesel engine of uniflow type was carried out by means of a test rig, which faithfully represents the phenomena in a fired engine, only using the compressed air separately charging and boosting the cylinder from different pressure sources. The experimental results show good agreement with those calculated and verify as a whole that the simple method of calculation proposed by the author may well be applicable to the practical purpose of evaluating the phenomena and the associated problems under design stage. At the same time, the results obtained with the test rig may be applied to presume the performance of the fired engine having the same exhaust and scavenging characteristics, though certain modifications are required according to the differences in temperature condition, etc.

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A hydrocarbon fuel has its inherent ignition property definitely related with its chemical structure, and, for the family of normal paraffins, the characteristic values may be supposed to increase with the carbon number. In this study, we investigated the nature of the inherent ignition property in such a way that the reductions in ignition lag in a CFR Diesel engine were measured when several kinds of normal paraffins higher than Cetane, liquid or solid, were mixed with or dissolved in a liquid paraffin base fuel to varied amount and the rate of ignition lag decrease was used for evaluation. Kogasin I (nearly Octane) was adopted as the base fuel, and two higher liquid paraffins (C₁₆ and C₁₇) and three solids (C₁₉, C_21·5, and C₈₁) were examined. It was found that the inherent ignition property increases with the carbon number irrespective of whether liquid or solid paraffins. The characteristic values obtained for C₁₇, C₁₉, C_21·5, and C₃₁ were 104, 115, 136, and 202 in terms of cetane value, respectively.

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