Journal of the Society of Materials Science, Japan

Loading Rate Dependency of Uniaxial Compressive Strength of Rock Under Water-Saturated Condition

Seisuke OKUBO, Yuichi NISHIMATSU, C. HE, Seok Yuen CHU

1992 Volume 41 Issue 463 Pages 403-409
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.403

JOURNAL FREE ACCESS

Show abstractHide abstract

Moisture has various effects on the behaviour of rocks. It is well known that the compressive strength decreases significantly with an increase of moisture content. Though many studies have been carried out concerning the effect of moisture, the influence on the time dependent behaviour is still open to discussion. It is very important to clarify its time dependence for analysing the long-term stability or durability of underground structures.
In this study, six rocks were tested in uniaxial compression under four loading rates C=10^-6, 10^-5, 10^-4 and 10^-3/sec. With an increase of loading rate, it was found for all samples that the strength increased and the stress-strain curve in the post-failure region shifted to the right-hand side. The slope of the stress-strain curve, however, did not change meaningfully with loading rate. It should be noted that the increase of strength with loading rate did not depend on moisture content.
The constitutive equation which is applicable to various time dependent behaviours was used to simulate the loading rate dependence under uniaxial compression tests. It was found that the calculated results gave a good approximation to the experimental results for all sample rocks.

View full abstract

Download PDF (898K)
Effect of High and Low Temperature on Failure Characteristics of Rocks under Compression

Yoshinori INADA, Yoshihiko KOKUDO

1992 Volume 41 Issue 463 Pages 410-416
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.410

JOURNAL FREE ACCESS

Show abstractHide abstract

In order to get the strength and deformation characteristics of Class II rocks which show a positive gradient in the post failure region of their stress-strain curves obtained by uniaxial compression tests, several methods have been tried and devised. One of them is a method of controlling the strain velocity and stress at the same time proposed by Nishimatsu et al.. However, this method needs a troublesome process to choose different gradients before and after failure. The present authors are proposing a method controlling the strain velocity before failure and then the stress and strain after failure.
In this study, the strength and deformation characteristics of rocks at high and low temperatures obtained by our method using a trial machine were described and discussed. The results are useful as the basic information to store high and low temperature materials in caverns in rock mass. The results obtained are as follows:
(1) The strengths of both Dry and Wet rocks used in this study, such as granite, andesite, sandstone and tuff, became lower with rising temperature and the strain at peak became larger.
(2) The returning gradient of Class II rocks in the post failure region of the stress-strain curve at high temperature became lower with rising temperature, while it was a gentle change in Class I rocks.
(3) The strength of rocks at low temperature became higher with falling temperature, and the strain at peak became smaller. On the other hand, the strength of wet tuff became higher, and the strain at peak became larger.
(4) The returning gradient of Class II rocks in the post failure region at the stress-strain curve at low temperature became larger with falling temperature, while it was a steep change in Class I rocks. On the other hand, the gradient of wet tuff became gentle with falling temperature.

View full abstract

Download PDF (768K)
Theoretical Construction of Bearing Characteristic Curve in Tunnelling

Hideo KIYAMA, Hisashi FUJIMURA, Tsuyoshi NISHIMURA, Yasuo IKEZOE

1992 Volume 41 Issue 463 Pages 417-423
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.417

JOURNAL FREE ACCESS

Show abstractHide abstract

Active mobilization of bearing capacity of surrounding rock mass characterizes the NATM concept of supporting. However, no quantitative expression of this bearing capacity has been recognized yet. In the present paper, “a support load of surrounding rock mass”, “a support load of lining” and “the total support load of a tunnel” for a two-dimensional elastic circular tunnel were quantitatively evaluated by using a common index, support-stiffness, which is defined as the relative stiffness of each support to the original stiffness of the rock removed from the opening.
By advancing the above analysis, the procedure to construct theoretically the bearing characteristic curve of elastic rock mass in tunnelling was discussed rationally. By applying the principles of this procedure to general rock mass with non-linear stress-strain property, various bearing characteristic curves were obtained from elastic type to elasto-plastic type, Fenner-Pacher type, or catastrophic type, depending on the initial earth pressure level related to the strength of the rock mass.

View full abstract

Download PDF (938K)
Rock Mass Classification Based on Convergence Measurement in Tunneling

Chikaosa TANIMOTO, Hisaya YOSHIOKA

1992 Volume 41 Issue 463 Pages 424-429
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.424

JOURNAL FREE ACCESS

Show abstractHide abstract

Convergence monitoring can be easily carried out during construction and provides serial information on final deformation of tunnel wall, support load, development of the inelastic zone, etc. The authors estimated the width of the inelastic zone from the results of convergence measurements which had been carried out in sedimentary rocks, and clarified the relationship between competence factor and deformation rate. It was concluded that the allowable limit of deformation in tunneling (ΔD/D) must not be beyond 2%.

View full abstract

Download PDF (817K)
Problems in Crosshole Seismic Tomography

Detectability of Inclined Layer

Masayuki YAMADA, Hideki SHIRAHATA, Koichi SASSA

1992 Volume 41 Issue 463 Pages 430-436
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.430

JOURNAL FREE ACCESS

Show abstractHide abstract

In the crosshole seismic tomography, sources and receivers are placed in two parallel boreholes. For this source-receiver geometry, it has been clarified in the previous paper that the layer perpendicular to the holes can be detected quite well, but one parallel to the holes is hardly reconstructed. In this study, both the detectability of inclined layers and the relation between inclined angle of the layer and observation pattern were investigated, and an effective method to detect inclined layers was proposed. The coordinates of tomographic analysis were rotated so as to coinside with the angle of inclined layers, and the accuracy of reconstructed image was discussed. It was clarified that the detectable angle of inclined layers was closely connected with the angle of seismic rays.

View full abstract

Download PDF (2521K)
A Study on Computerized Image Reconstruction of Electrical Resistance in Earth by Extended Differential Sensitivity Distribution Method

Tsuyoshi SUGANO

1992 Volume 41 Issue 463 Pages 437-443
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.437

JOURNAL FREE ACCESS

Show abstractHide abstract

In order to improve the reliability of electrical prospecting methods, it is necessary to measure voltage more sensitively so as to reflect target inhomogeneity in complex field conditions, to design more effective solid resistivity array combinations and patterns, or to develop additional new tomographic information under more restricted practical conditions, based on applicable electrical methods.
In this study, a differential sensitivity distribution technique was newly developed and the computerized resistivity image section of the earth or material interior structure was constructed to examine the effectiveness of the new method. It was found that the pure differential sensitivity and the extended differential sensitivity distribution theorems could give very useful information and knowledge to improve the reliability of the conventional electrical tomography image reconstruction.

View full abstract

Download PDF (2349K)
Microscopic Observation and Uniaxial Extension Testing on Coated Plain-weave Fabrics

Hirokazu MINAMI, Hiroshi TOYODA, YING Wu

1992 Volume 41 Issue 463 Pages 445-450
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.445

JOURNAL FREE ACCESS

Show abstractHide abstract

Coated plain-weave fabrics are used as a membrane material of membrane structures including architectural membrane structures such as clear span air-supported membrane structure, flexible containers and airships. Uni/biaxial extension properties of coated fabrics are vary important for the design of membrane structures. In the present paper, the authors first presented SEM photographs of the surface and cut section to understand the structure of this material. Then unidirectional tensile tests were done up to failure. The stress-strain curves showed nonlineality and anisotropy. Some discussion was done on these properties. Poisson's ratio showed extreme nonlinearity at the stress region up to 20% of the failure stress which is the design stress. Specimens used here were a PTFE-coated grass fiber fabric and a PVC-coated polyester fabric which are widely used in the field of architectural membrane structure.

View full abstract

Download PDF (2931K)
Biaxial Extension Testings on Coated Plain-weave Fabrics

Hirokazu MINAMI, Shinya SEGAWA

1992 Volume 41 Issue 463 Pages 451-457
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.451

JOURNAL FREE ACCESS

Show abstractHide abstract

The membrane materials are generally in various states of biaxial deformation in membrane structures, and also have visco-elasticity in addition to the peculiar nonlinearity. The biaxial extension curves, therefore, should be measured under the experimental conditions of iterative extension and various tensile speeds. In this paper, the authors selected PTFE coated plain-weave glass fiber and PVC coated plain-weave polyester fiber fabrics as the specimens, and measured the uni/biaxial extension curves up to the design stress (assumed to be 20% of the uniaxial breaking stress) under the experimental conditions of iterative extension and two different tensile speeds. The nonlinearity, the slope, and the iteration time up to convergence of the extension curves were studied. The dependences of these factors on tensile speed were also discussed. The main result of discussions was that the slope of extension curves depended upon tensile speed.

View full abstract

Download PDF (1426K)
A Constitutive Equation of Creep, Swelling and Damage Under Neutron Irradiation Applicable to Multiaxial and Variable States of Stress

Sumio MURAKAMI, Mamoru MIZUNO

1992 Volume 41 Issue 463 Pages 458-464
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.458

JOURNAL FREE ACCESS

Show abstractHide abstract

A constitutive equation of creep, swelling and damage under neutron irradiation applicable to multiaxial non-steady states of stress is developed. In the formulation of the constitutive equation, the creep under irradiation was divided into irradiation-affected thermal creep and irradiation-induced creep. Then the irradiation-affected thermal creep was formulated by extending the creep-hardening surface model to include the effects of neutron-irradiation and material damage. The Bailey-Norton creep law and Kachanov-Rabotnov creep-damage theory were employed. The effect of irradiation on thermal creep was described by expressing the material functions of the constitutive equation as functions of neutron flux φ and neutron fluence Φ. The constitutive equation of irradiation-induced creep was formulated by taking account of SIPA and CCG mechanisms and by representing the creep rate as a function of stress of order zero and one. Creep of 316 stainless steel under various conditions of irradiation and variable stress was analyzed in order to elucidate the validity and the utility of the proposed constitutive equation.

View full abstract

Download PDF (947K)
Time-Temperature Dependences of Mechanical Properties of High Temperature Epoxy Resin and CFRP Laminates Using the Resin

Masato KASAMORI, Takeru OHTSUKA, Minoru SHIMBO, Yasushi MIYANO

1992 Volume 41 Issue 463 Pages 465-469
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.465

JOURNAL FREE ACCESS

Show abstractHide abstract

This paper is concerned with the time and temperature dependences of the static flexural behavior in CFRP laminates consisting of high temperature epoxy matrix and satin woven carbon fibers. Dynamic viscoelastic tests for neat resin and three-point bending tests for CFRP laminates were carried out under various loading rates and temperatures. The results obtained are summarized as follows;
(1) The mechanical behavior of epoxy resin used was remarkably dependent upon time and temperature even in the vicinity of room temperature that is sufficiently lower than the glass transition temperature T_g.
(2) The static flexural strength of CFRP laminates was also remarkably dependent upon time and temperature over a wide range of temperature even below T_g.
(3) The time and temperature dependences of the static flexural strength of CFRP laminates was dominated by the mechanical behavior of matrix resin.

View full abstract

Download PDF (1258K)
Impact Fracture of Austempered and Hot-Rolled Spheroidal Graphite Cast Iron

Hisakichi SUNADA

1992 Volume 41 Issue 463 Pages 470-474
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.470

JOURNAL FREE ACCESS

Show abstractHide abstract

Commercially produced ferritic spheroidal graphite cast iron was used in this study. The materials tested were prepared in two ways, austempering and hot-rolling. The austempering was done either at 573K or at 673K by quenching into salt bath and holding for 5min or 2hr after austenitization at 1173K for 1hr. Finally the materials were hot rolled at temperatures ranging from 1173 to 1073K.
Charpy impact tests were carried out using a V-notched small test specimen (5mm×5mm×55mm) in the temperature range of 77-430K. The results obtained are summarized as follows;
(1) The austempering at 573K elevated the tensile strength and hardness in comparison with that at 673K, while it lowered the impact value.
(2) Both the tensile strength and absorbed energy were lowered by the rolling, because the cracks coalesced easily as a result of the narrower spacing of graphites.
(3) The transition temperature determined by a mean value of the upper and the lower energy absorbed can be written in this order: ferrite<upper bainite<lower bainite<rolled ferrite
(4) The absorbed energy was correlated with the size of the plastic zone ahead of the notch.

View full abstract

Download PDF (3053K)
Fracture Toughness of HTGR Graphites

Shintarou ISHIYAMA, Motokuni ETO

1992 Volume 41 Issue 463 Pages 475-481
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.475

JOURNAL FREE ACCESS

Show abstractHide abstract

Fracture toughness tests were carried out on nuclear graphite, IG-110 and PGX, and the effects of width, ligament ratio of compact tension specimen and cross-head speed on fracture toughness were examined. Crack extension processes in graphite specimen were observed by acoustic emission technique and optical observation method. From the results, it is concluded that:
(1) A knee-point on the electrical potential-load displacement curve indicates macro-cracking in compact tension specimens.
(2) Cracking occurred in the middle part of the notched surface of compact tension specimen and extended from the middle to the surface of specimen.
(3) The value of J_IC was constant within the range of ligament ratio from 0.4 to 0.55.
(4) The value of J_IC was constant within the range of cross-head speed from 0.005mm/min to 0.05mm/min.
(5) The value of J_IC was constant when the specimen width was more than 10mm for PGX graphite and 20mm for IG-110 graphite, respectively. However, J_IC decreased as the specimen width decreased below the above-mentioned values. It is considered that this phenomenon is due to the formation of process-zone at the crack front of CT specimen.

View full abstract

Download PDF (914K)
Influence of Microcracking on Fracture Toughness of TiO₂ Sintered Body

Kouichi YASUDA, Shigenari OHSAWA, Yohtaro MATSUO, Shiushichi KIMURA

1992 Volume 41 Issue 463 Pages 482-487
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.482

JOURNAL FREE ACCESS

Show abstractHide abstract

Pressureless sintered TiO₂ bodies were annealed to change their grain sizes from 10μm to 59μm. Microstructural observations of the specimens indicated that the spontaneous critical grain size of TiO₂ was about 20μm, and the mean length of network of microcracks was about 1.5mm. The thermal expansion analysis indicated that the volume fraction of spontaneous microcracks was about 1.5×10^-3. The grain size dependences of Young's modulus and fracture stress ensured the spontaneous microcracking. Fracture toughness K_IC was measured by a chevron-notched beam method. K_IC took a constant value below the critical grain size, but it was reduced to about 65% above the critical grain size. The reduction of K_IC could be estimated quantitatively using the length and volume fraction of microcracks.

View full abstract

Download PDF (1506K)
Fracture Toughness of Single Crystal Silicon at High Temperatures

Kunio HAYASHI, Shinji TSUJIMOTO, Yasunori OKAMOTO, Tomozo NISHIKAWA

1992 Volume 41 Issue 463 Pages 488-494
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.488

JOURNAL FREE ACCESS

Show abstractHide abstract

The fracture toughness (K_IC) on the major planes of single crystal silicon was measured by the controlled surface flaw (CSF) and indentation fracture (IF) methods at high temperatures. The K_IC values obtained by the CSF method for the surface orientations {100}, {110}, {111} and {112} of silicon up to about 500°C decreased with increasing temperature. In the low temperature region, the linear decrease of K_IC for {110}, {111}, and {112}, excepting for {100}, was explained on the basis of an elastic model. The K_IC values for {100}, {110}, {111} and {112} planes of silicon increased rapidly over the temperatures of 500, 600, 700 and 800°C, respectively.
It was found that the rapid K_IC increase for those planes of silicon at the individual critical temperatures was attributable to extensive plastic yielding in the vicinity of the crack tips relating the Schmid factor and numbers of slip systems for each planes. The K_IC values obtained by the IF method in the range from 400 to 600°C were larger than those obtained by the CSF method for all planes. The trend of increase in K_IC values by the former method in the high temperature region agreed with that by the later method.

View full abstract

Download PDF (2856K)
Crack Size Effect on Crack Propagation Behavior and Experimental Verification of Cyclic Fatigue Mechanism of Sintered Silicon Nitride

Akira UENO, Hidehiro KISHIMOTO, Hiroshi KAWAMOTO, Youichi YAMANAKA

1992 Volume 41 Issue 463 Pages 495-501
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.495

JOURNAL FREE ACCESS

Show abstractHide abstract

In order to investigate the effect of crack size on the crack propagation behavior of a sintered silicon nitride, crack propagation tests were conducted under cyclic loads and static load. Two different sizes of small surface semielliptical cracks were introduced by Knoop indentation. By polishing the surface layer, the residual stress caused by Knoop indentation was perfectly removed. The crack propagation rates of small cracks (350μm, 200μm) were slower than that of a long crack obtained with CT specimen. Analyzing the crack opening displacement (COD) of the 350μm crack, we could determine the quantity of the true stress intensity factor K_Itip·K_Itip was expressed as K_Itip=K_Imax-K_s, where K_s is a component of the stress intensity factor shielded by bridging effects. Furthermore, we found that the COD after cyclic loading was larger than that before cyclic loading. It is evident that the increase in COD after cyclic loading was originated from the reduction of bridging force with cyclic fretting at the bridging sites under cyclic loads. It was concluded that the reduction of bridging force made the K_Itip increase and increased K_Itip accelerated the crack propagation rate.

View full abstract

Download PDF (2306K)
The Effect of Microstructure on Fatigue Crack Growth in Ti-6Al-4V Alloy

Takeshi OGAWA, Kohji OHYA, Keiro TOKAJI

1992 Volume 41 Issue 463 Pages 502-508
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.502

JOURNAL FREE ACCESS

Show abstractHide abstract

The characteristics of fatigue crack growth were investigated in Ti-6Al-4V alloy with three kinds of microstructure prepared with different heat treatments. The effect of microstructure on the crack growth behavior was attributed to the development of crack tip shielding, primarily resulting from the role of the crack path morphology in inducing crack closure and crack deflection. Roughness induced crack closure played an important role on the near-threshold growth behavior at the load ratio of 0.05, but the growth rate data plotted in terms of effective stress intensity factor range ΔK_eff (after allowing for closure) still exhibited the effect of microstructure. Fractographic observations were performed using a scanning electron microscope (SEM) with the aid of image processing, which enables the three dimensional observation using a stereo pair of SEM micrographs. The roughness was evaluated quantitatively by the ratio of the total area of the three dimensional fracture surface to its projected area. As the fracture surface roughness was taken into account in re-evaluating the crack growth characteristics, the effect of microstructure disappeared, indicating that the intrinsic crack growth resistance was the same for all microstructure. Thus, fracture surface roughness is a controlling parameter of the fatigue crack growth in Ti-6Al-4V alloy. Furthermore, the crack growth rate were compared with those of other structural materials such as steels, nodular cast iron and an aluminum alloy.

View full abstract

Download PDF (2747K)
Measurement of Variable Amplitude Stress Utilizing the Density of Slip Bands

Yasuo NAGASE, Yozo SAWAKI, Hajime YOSHIDA

1992 Volume 41 Issue 463 Pages 509-515
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.509

JOURNAL FREE ACCESS

Show abstractHide abstract

In order to evaluate the stress of a machine part subjected to variable stress amplitude, the density of fatigue slip bands produced on aluminum foil is proposed as a measure for this purpose. The fundamental characteristics of slip band formation were examined under both constant and variable amplitude stresses. It was found that the density of slip bands was dependent on both the stress amplitude and the number of stress cycles. The variation of stress amplitude hardly affected the increase of the slip bands in successive stress cycles, irrespectively of the variable mode of stress. The density of slip bands under variable loading, f_s was well correlated with the equivalent stress, σ_eq=(Σσ^α_iN_i/ΣN_i)^1/α, where σ_i, N_i and α are stress amplitude, the number of stress cycles at σ_i, and a material constant determined from an aluminum foil used, respectively. It is concluded that the equivalent stress can be evaluated by the density of slip bands produced on aluminum foil, using the relationship between f_s and applied stress amplitude obtained under constant loading. The accuracy of measuring the equivalent stress was within 3%.

View full abstract

Download PDF (1590K)
Evaluation of Thermal Shock Resistance for Cast Epoxy Resin with Various Toughness

Masatoshi KUBOUCHI, Ken TSUDA, Masayuki MOTOHASHI, Hidemitsu HOJO

1992 Volume 41 Issue 463 Pages 516-522
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.516

JOURNAL FREE ACCESS

Show abstractHide abstract

Previously the present authors proposed the testing method of thermal shock resistance using a notched disk type specimen of brittle type epoxy resin and its evaluation method based on fracture mechanics. In order to examine their applicability, some practical epoxy resins for casting were tested in this study.
For brittle alicyclic epoxy resin, irrespective of the cooling bath temperature, the nondimensional stress intensity factor calculated by the experimental results agreed well with that of theoretical estimation.
In the case of mixed resin of bisphenol A epoxy having certain toughness and very brittle alicyclic epoxy, the critical temperature difference ΔT_C was clearly recognized for all resin systems with various mixture ratios, and the resin with higher bisphenol A epoxy content showed higher thermal shock resistance. For the bisphenol A type epoxy resin with longer molecular chains (larger number of repeated units) indicated higher resistance. The analysis agreed well with the experiments for these both resin systems.
For the epoxy resin modified with a low content of plasticizer, the same evaluation method of thermal shock resistance was found to be applicable. But over 20phr content, plastic flow occurred markedly, and so the critical temperature difference could not be obtained. For such cases, it is still possible to evaluate the thermal shock resistance by using a large size specimen.

View full abstract

Download PDF (1836K)
Carrier Transport Mechanism of TiO₂ Encapsulated in Polymethylmethacrylate by Time-of-Flight

Yutaka HAGA, Ryutoku YOSOMIYA

1992 Volume 41 Issue 463 Pages 523-527
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.523

JOURNAL FREE ACCESS

Show abstractHide abstract

The carrier mobilities and carrier transport mechanism of composite materials of TiO₂ encapsulated in polymethylmethacrylate (C-PMMA-TiO₂) were investigated by the Time-of-Flight (TOF) method. As the result, the drift mobility of C-PMMA-TiO₂ increased as compared with that of TiO₂, and its value showed a tendency to increase with an increase of encapsulating ratio. The increase of drift mobility of electrons became larger than that of holes. Since the dispersion parameter α showed the temperature dependence, it was considered that the mechanism of carrier transport in C-PMMA-TiO₂ was the limited transport of carriers captured by the localized levels existing in an exponential distribution. Furthermore, it was found that the density of the localized level increased with increasing encapsulating ratio.

View full abstract

Download PDF (601K)
Schematic Representation for Evaluating Adhesive Strength of Wood Component

Takanori ARIMA, Syunji HAYAMURA, Noriyoshi MARUYAMA

1992 Volume 41 Issue 463 Pages 528-534
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.528

JOURNAL FREE ACCESS

Show abstractHide abstract

More efficient use of construction adhesives as structural fasteners requires detailed knowledge on the behavior of adhesive joints between load-bearing building components under actual service conditions. As the strength of adhesive joint depends on the shear strength of wood as well as the strengths of adhesive and its bonded surfaces, both the strength of adhesive joint and the percentage of wood failure are provided as the test indicators. In this report, the relationship between the shear strength of adhesive joint and the percentage of wood failure was derived from the strength of wood and adhesive. The proposed schematic representation showing the distributions, of shear strength and of wood failure can be a powerful tool for evaluating how the strength changes with time or under accelerated aging, or which of the degrading factors is the major one. Based on observation of the shear test and the appearance of the fractured adhesive, interpretation of the results and recognition of the estimates under aging will become easier. A recent inspection of adhesive joints for glue-laminated timber after 6 years outdoor exposures shows that the rate of change in joint strength is attributable to the wood degradation and no adhesive failure occurs.

View full abstract

Download PDF (860K)
Strength Evaluation and Safety of Machine/Structure

3. Case Examples on Strength and Safety Evaluation of Machine/Structure 3·1 Automobil

M. Tsuboi

1992 Volume 41 Issue 463 Pages 535-539
Published: April 15, 1992
Released on J-STAGE: June 03, 2009

DOIhttps://doi.org/10.2472/jsms.41.535

JOURNAL FREE ACCESS

Download PDF (705K)

Register with J-STAGE for free!