Journal of the Society of Materials Science, Japan

Ceramics-their Possibility of Ultra-High Strength Materials

Shin-ichi HYODO

1974 Volume 23 Issue 255 Pages 1027-1033
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1027

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Relation between the Stress Measured by X-Ray and the Stress Indicated from Brittle Lacquer Coating

Jyunichi ARIMA, Yasuyoshi IWAI

1974 Volume 23 Issue 255 Pages 1034-1038
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1034

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The stress measurement by X-rays is based on the variation of lattice spacings of metallic crystals due to stress. It has been noted as a unique method of measuring nondestructively the local stress, especially residual stress. Recently, this X-rays stress measurement has been applied in a very wide field of engineering studies in consequence of development of X-ray equipments as well as improvement in measuring devices.
On the other hand, the stress measurement with a brittle lacquer coating is based on the crack development perpendicular to the tensile strain when the loading exceeds a certain value. In this method, the direction of principal stress and the position of stress concentration can be determined directly from the crack patterns on the specimen surface. In comparison with other stress measuring methods, however, the lacquer coating technique has not been widely employed in engineering because of its lower strain sensitivity and the susceptibility to the influence of lacquer ingredients, drying techniques, or conditions of temperature and humidity.
In this paper, the authors report the practical usefulness of infrared rays baking device for brittle lacquer of baking type. Moreover, the stress values on plain carbon steel plates determined by the lacquer coating were compared with those by the X-ray method in their elastic range during bending tests.
The results obtained are as follows:
(1) The measured temperature of a specimen coressponded well with the preset temperature of the baking device, showing the practical usefulness of the device.
(2) The stresses obtained by using the lacquer coating and the X-ray techniques at any stage of bending tests in the elastic region agreed well each other in the range from 4kg/mm² to 20kg/mm².
It seems easy to make a reliable stress measurement by X-ray even on the complex machine parts or structures, if the direction of principal stress and the pattern of stress distribution are preliminarily analysed by the brittle lacquer coating method.

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Errors in Estimated Value of Air Voids Content of Marshall Test Specimen

Shoji OGINO

1974 Volume 23 Issue 255 Pages 1039-1044
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1039

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In the Marshall test, the percentage of air voids has been used as a basis to determine the asphalt content. But, it is not easy to determine accurately the value of air voids of a compacted asphalt mixture. According to the author's experience, it is not rare to have the case that the calculated value of air voids content becomes negative.
In this paper, in order to clarify the reason why the value of air voids content sometimes becomes too small an attempt was made to determine the effects of the following three factors on the calculated value of air voids content: (1) Method of measuring the volume of specimens, (2) method of measuring the specific gravity of aggregates, and (3) difference between the specified and the true asphalt content of compacted test specimens.
From the results of the investigation, the following conclusions were drawn.
(1) The method of measuring the volume of compacted specimens affects the calculated value of air voids content. A minimum value was obtained when the volume was measured with paraffin coating.
(2) The method of measuring the specific gravity of aggregates also affects the value of air voids content. A minimum value was obtained when the bulk specific gravity was used.
(3) When a large amount of asphalt is used, some of it adheres to the mixing and molding apparatus during the preparation of specimen. As the result, the value of air voids content calculated using the specified asphalt content is smaller than the true air voids.

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An Effect of Testing Conditions on Fatigue Strength of Selected Rigid Plastics

Shoji SHIMAMURA, Nobusuke ENOMOTO, Harumi FURUE, Kazuo KOMAKI, Haruo N ...

1974 Volume 23 Issue 255 Pages 1045-1049
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1045

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Three selected rigid plastics, namely polymethyl-methacrylate, polyvinyl chloride and glass-cloth reinforced polyester, were subjected to fatigue tests with four different fatigue testing machines. The results showed the following effect of the fatigue tester on the fatigue strengths of these materials.
(1) The effect of testing machine on the fatigue strength is appreciable. Therefore, a careful comparison of fatigue data resulting from the tests with different fatigue testers is necessary.
(2) The difference in the type of fatigue testing machines employed (constant stress-amplitude or constant strain-amplitude) as well as the difference in the method of holding specimens may affect the fatigue strength.

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Mechanical Properties of Polymer Impregnated Concrete Polymerized by Gamma-Rays

Sakichi OHGISHI, Hironobu ONO, Isamu TANAHASHI, Kunio ARAKI, Yuko KASA ...

1974 Volume 23 Issue 255 Pages 1050-1056
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1050

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In the present paper, the relationship between the strength of PIC and the total exposure dosage of gamma-rays was discussed for the mortar specimens containing MMA monomer cured by the irradiation at the dose rate of (1.25, 2.5, 5 and 10)×10⁵ Roentogen/hr. In addition, the effects of the turning irradiation, wrapping and annealing were examined, and the strength of PIC polymerized by the radiation method was compared with that of PIC polymerized by the thermal catalytic initiation method.
The results show that the total radiation dosage for polymerization to obtain the desirable MMA-PIC strength is 4MR at 10⁶R/hr dose rate, 3MR at 5×10⁵R/hr, about 2.5MR at 2.5×10⁵R/hr and 2MR at 1.25×10³R/hr. These values change depending upon the ambient temperature in the radiation cave. If the polymerization is carried out under an appropriate condition, the characteristics of PIC, obtained by both the thermal catalytic initiation method and the radiation polymerizing method, are the same. The effect of annealing on PIC strength is negligibly small in the temperature range lower than 100°C. Therefore, it is necessary to make the annealing temperature higher than 100°C. No effect of the turning irradiation was found out.

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Time-Temperature Dependence of GRP Plate under Flexural Loading

Yasushi MIYANO, Katuhito SUZUKI

1974 Volume 23 Issue 255 Pages 1057-1062
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1057

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This paper is concerned with the time- and temperature dependences of the bending properties of the plain fabric glass cloth reinforced laminates (GRP) and the unsaturated polyester resins which are the matrices of the GRP.
The results obtained are summarized as follows:
(1) The creep compliances of the matrix and the GRP show the remarkable time- and temperature dependences; that is, they have so called viscoelastic behaviors.
(2) The master curves of the creep compliances for both the matrix and the GRP can be constructed, using their thermo-rheological simple properties. As for the time- and temperature shift factors, they are in good agreement quantitatively.
(3) It was found that the relation between the creep compliances of the matrix and the GRP is uniquely determined by the rule of mixture for viscoelastic materials, independent of the conditions of their circumstance such as time and temperature. This was also confirmed experimentally.

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Experimental Investigation on the Influence of Temperature, Humidity (Moisture Content) and Stalk Position on Tensile Characteristics of Tobacco

Kohei SAITO

1974 Volume 23 Issue 255 Pages 1063-1069
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1063

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For the purpose of quantitatively distinguishing the influences of temperature (t), humidity (h), leaf position in a tobacco stalk (p) and direction in a leaf, upon the tensile characteristics or equilibrium moisture content of tobacco (Y), statistical calculations were carried out with many data on typical varieties in Japan, that is, Flue-cured (v₁) and Domestic variety (v₂). And the following formula to estimate Y was analyzed (Table III).
Y=C₀+C₁t+C₂h+C₃h²+C₄p+C₅p²
After that, the relation between tensile characteristics and equilibrium moisture content (w) was searched with the formula Y.
The important results obtained were as follows:
(1) Tensile strength (P_m)
The P_m of v₁ was greater than that of v₂. The P_m of v₁ was decreased when the h(w) or t was increased, but the P_m of v₂ did not show any notable tendency with the h (w) or t. In every variety the P_m was decreased toward the lower position in a stalk (Fig. 3 and 4).
(2) Elongation percentage (ε)
The ε of v₁ was higher than that of v₂. In every variety the ε was increased when the h (w) or t was increased, and toward the upper position in a stalk (Fig. 3 and 4).
(3) Elastic modulus (E) and Elasticity per unit dry weight (E_G)
The E of v₁ was smaller than that of v₂. In every variety the E was decreased when the h (w) or t was increased. In the variety v₁ the E became minimum at the upper or middle position of a stalk, and was increased toward the lower position. This tendency was shown in the variety v₂ too, but the degree of change with the stalk position in the v₂ was smaller than that in the v₁. The appearance of the change in the E_G was very similar to the above-mentioned results in the E (Fig. 5 and 6).
(4) The influence of w on tensile characteristics (P_m, ε, E or E_G) was very much greater than that of t (Fig. 4 and 6).

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A New Moiré Fringe-Strain Relation and A Method for the Determination of the Strain Sign

Kazumi MURAKAMI, Sadanori ITO, Yasunori MURAKAMI

1974 Volume 23 Issue 255 Pages 1070-1074
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1070

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The conventional moiré interfringe spacing-strain relation does not contain a factor for determining the strain sign. Therefore, in the case of complex strain fields, this equation can not give exact strain values.
In this paper, new equations for the fringe-strain relation are derived. These expressions contain new factors M_ii and M_ij (±1) for determining the strain sign. The factors can easily be determined by shifting the master grid in the direction perpendicular to the grid lines.
When the crossed grid is used, the discrimination of two kinds of fringes produced by X and Y grid is generally difficult. However, it is proposed that the above mentioned shifting method is also an effective means for the discrimination of both fringes.

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Property of Moiré Fringes and Problems Associated with Measurement of Large Strains

The Highest Measurable Limit of Strain and the Way to Eliminate it

Kazumi MURAKAMI, Yasunori MURAKAMI

1974 Volume 23 Issue 255 Pages 1075-1079
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1075

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The authors previously pointed out that when measuring small strains by the moiré method the lowest measurable limit inherent in this method must be taken into consideration. On the contrary, in applying this method to the measurement of large strains, one should consider the highest measurable limit of strain.
This paper deals with the property of the moiré fringes studied from the physiological view point to clarify the highest measurable limit of strain that exists inherently in this method. In our theory, the highest measurable limit of normal strain ε_i(i=x or y) can be expressed as
2cosα_i/3(1+λ)cosθ-1<ε_i<3cosα_i/2(1+λ)cosθ-1
where α_i are shear strain components, λ and θ are values of mismatch and misalignment, respectively.
The highest measurable limit mentioned above can be avoided in the practical measurement by selecting the value of λ properly.

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The Measurement of Fiber Volume Content in FRP by Ultrasonic Wave Method

Shigeaki YOMODA, Masataka ONO, Hiroshi MAKI

1974 Volume 23 Issue 255 Pages 1080-1085
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1080

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A method was devised to determine the fiber volume content (V_f) in FRP by the ultrasonic wave technique. When the ultrasonic wave length was shorter than the diameter of the fiber, V_f could be easily determined by this method.
However, when the ultrasonic wave length was longer than the diameter of the fiber, V_f could not be determined by the ultrasonic wave method only, but it was necessary to use an approximate solution for the transverse rigidity of FRP under the test.
The fiber volume contents of glass FRP and carbon FRP determined by this non-destructive method were in good agreement with those determined by the commonly-used destructive method.

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Rational Mechanics-New Continuum Mechanics

Chapter 3. Simple Materials

T. Tokuoka

1974 Volume 23 Issue 255 Pages 1086-1091
Published: December 15, 1974
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.23.1086

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