bluuebunny/crossref_metadata_2025 huggingface dataset:
Caseload Management Skills for Improved Efficiency
Authors: Ervin Naomi E.
Published: March 2009

This article provides information about caseload management, which was one of a group of six competencies identified by nurse administrators as needed by new baccalaureate graduates. Caseload management is an important skill for nurses who work with caseloads of patients or clients (e.g., home health nurses, public health nurses, case managers, ambulatory care nurses). Because inadequate information about caseload management is contained in community health nursing textbooks, continuing education and staff development programs need to include caseload management skills to improve the efficiency and quality of nursing care.
Pertussis Infection in a Baccalaureate Nursing Program: Clinical Implications, Emerging Issues, and Recommendations
Authors: Matthews Ellyn , Armstrong Gail , Spencer Tammy
Published: March 2009

Pertussis is a significant public health problem with a dramatic rise in reported cases. Academic and clinical nursing educators are challenged to develop policies based on evolving national immunization guidelines. Of relevance to clinical educators, several outbreaks involving health care facilities and universities have been reported in the past few decades because of failure to adequately recognize pertussis infection and treat disease spread among adults and lack of control measures. The purpose of this article is to present information about pertussis transmission in a baccalaureate nursing program, outline actions taken, and explore emerging issues and recommendations.

J Contin Educ Nurs
2008;39(9):419–426.
Developing Your Career as a Nurse Educator: Networking and Peer Review
Authors: Billings Diane M. , Kowalski Karren
Published: March 2009

This column provides “tips” for developing your career as a nurse educator through networking and peer review.

J Contin Educ Nurs
2008;39(10):439–440.
Rapid Response Teams: A Proactive Critical Care Approach
Authors: Twedell Diane , Moore Kim
Published: March 2009

Time and again, hospital code teams are dispatched to a patient in cardiac arrest only to find their resuscitative efforts unsuccessful. Are there earlier interventions that may have saved the patient? Do any warning signs exist before the patient actually goes into a full code or cardiac arrest event? The answer is a repeated yes, and the solution is a rapid response team.

J Contin Educ Nurs
2008;39(11):488–489.
Rural Perceptions of Continuing Professional Education
Authors: Jukkala Angela M. , Henly Susan J. , Lindeke Linda L.
Published: March 2009

Background:

This study describes rural health care professionals' perceptions about professional isolation and the availability, accessibility, and relevance of continuing education.

Methods:

Registered nurses (
n
= 165) and physicians (
n
= 59) providing health care services in 26 rural hospitals in two Midwestern states participated in the study.

Results:

Rural health care providers experience barriers to accessing relevant continuing education. Although physicians reported higher levels of professional isolation than their nurse counterparts, professional isolation was identified as a concern by both provider groups.

Conclusions:

To ensure an adequate supply of knowledgeable and skillful rural health care professionals, continuing education specific to the delivery of care in rural settings is necessary. Once developed, the continuing education must be delivered in a manner that is acceptable and accessible to isolated rural providers.

J Contin Educ Nurs
2008;39(12):555–563.
The Decision Making Process of: Older Adults Who Elect to Receive ECT
Authors: Amazon Jody , McNeely Elizabeth , Lehr Sally , Marquardt Martha G.
Published: March 2009

Although there is extensive literature on electroconvulsive therapy (ECT), little documentation exists about how an individual makes the decision to receive ECT. This phenomenological study is an exploratory examination of the decision making process of older adults with mental illness who elect to receive ECT. Study participants included 7 older adults without dementia from a suburban geriatric medicine/psychiatry practice who elected to receive ECT. The lived experience of decision making as perceived by these 7 participants was a process that moved them toward wellness. The data revealed four significant themes: Support, Trust, Past Experience, and Desperation. An overriding substantive theme identified as an obstacle was the Stigma of Mental Illness. This study provided a basis for planning clinical practice and building further research.
Understanding the Placebo Effect: Part 1: Placebo Use in Clinical Trials
Authors: Howland Robert H.
Published: March 2009

The concept of a placebo—what it is, what it does, and how it works—is very complex. In this article, I discuss some important aspects of the placebo effect on the basis of clinical research studies in pharmacology. The prevalence and magnitude of a placebo effect depend on how the clinical-placebo effect is measured, the characteristics of the condition being studied, and the experimental or clinical context in which the placebo is administered.Although the placebo effect is real, placebos are unlikely to work as effectively in real-world settings. Next month's article will describe important findings about the psychological and neurobiological processes that underlie the placebo effect.
Replacing the Revolving Door: A Collaborative Approach to Treating Individuals in Crisis
Authors: Lauer Michelle , Brownstein Rose
Published: March 2009

The Crisis Assessment and Psychiatric Emergency Services (CAPES) unit was designed to improve the quality of psychiatric treatment, contain costs, and provide relief to overburdened psychiatric inpatient and emergency services in Delaware. This innovative program is the result of collaboration between public and private agencies to treat individuals in crisis. The myriad factors that contributed to a broken system and instigated Delaware's search for a solution are discussed in this article. The CAPES unit has resulted in improved communication among providers, decreased committal rates, better linkage to appropriate levels of care, increased safety, and improved coordination of services. Clinical implications for nursing practice include providing more holistic care in a safer environment.
Web-Based Treatment of Alcohol Problems Among Rural Women: Results of a Randomized Pilot Investigation
Authors: Finfgeld-Connett Deborah , Madsen Richard
Published: March 2009

It is estimated that 6 million women in the United States misuse alcohol. Of that number, many live in rural areas and face numerous barriers to treatment. The World Wide Web has the potential to help such individuals overcome these barriers. In light of emergent findings supporting the effectiveness of online alcohol treatment services for women, a randomized pilot study was conducted to evaluate a Web-based, self-guided alcohol treatment program. Eligible women were randomized to standard care or an online treatment program. Web-based treatment components included gender-specific reference modules and decision making modules, an asynchronous bulletin board, and a synchronous chat feature. The average age of the participants (
N
= 44) was 50 (
SD
= 11 years), and their baseline Alcohol Use Disorders Identification Test score was 18 (
SD
= 6), with 8 being the cut-off score for problem drinking. At 3-month follow up, both treatment groups decreased their drinking; however, no significant differences were found between them.
Behavioral Health Staff's Perceptions of Pet-Assisted Therapy: An Exploration Study
Authors: Rossetti Jeanette , DeFabis Susanne , Belpedio Camille
Published: March 2009

The purpose and objectives of this exploratory descriptive study were threefold: to assess the impact of pet-assisted therapy on the overall well-being of behavioral health staff, to document whether pet-assisted therapy affected the retention of behavioral health staff, and to explore and describe therapeutic measures behavioral health staff implemented in using pet-assisted therapy in the delivery of mental health patient care. The participants in this study were 10 behavioral health staff members who were involved with the pet-assisted therapy program at a private psychiatric hospital in a Chicago suburb. Themes that emerged from the study included Self-Awareness, Morale, Innovative Therapeutic Strategies, Challenges, and Future Directions. This article describes these themes in detail, provides quotations from participants to further highlight meaning, and discusses the powerful effect of pet-assisted therapy on both patients and staff in the therapeutic milieu.
Crack Propagation Toughness of Rock for the Range of Low to Very High Crack Speeds
Authors: Bertram A. , Kalthoff J.F.
Published: March 2009

A fracture mechanics characterization is performed of mode-I crack propagation processes in Solnhofen limestone. High levels of crack propagation velocity in the rock are generated by provid- ing high levels of elastic energy that are stored at the tip of the initial notch at the moment of initiation. This is experimentally achieved by subjecting the initial notch to impact loading conditions and/or by initiating the mode-I crack from a shear (mode-II) loaded starter notch. The dynamic stress intensity factors and the velocity of the propagating cracks are measured by a chain of strain gauges positioned along the prospective crack propagation path. The strain gauge measuring technique is used in an optimized form to reduce the influence of higher order terms of the crack tip stress field. Cracks are accelerated to velocities up to about 2000 m/s. The measured fracture toughnesses are significantly (almost a factor of ten) higher than the crack initiation toughness. Thus, the energy dissipated by a crack propagating at a high velocity is almost two orders of magnitude larger than the energy to ini- tiate a crack. Furthermore, the data show a sharp increase of the fracture toughness in the regime of slow crack propagation velocities. The fracture toughness crack velocity dependence shows a R-curve behaviour as typically found for ductile steels. The results explain characteristic peculiarities of the crack propagation behaviour of brittle fracture in rock.
Aging of High Speed Train Wheelsets and its Quantitative Characteristics Based on Fracture Mechanics for Optimization of In-Service Inspection
Authors: Kwon Sung Jae , Ogawa Kazuhiro , Shoji Tetsuo
Published: March 2009

The fracture mechanics characteristics in the critical locations of the wheelset for high-speed train have not been studied enough yet despite of severe conditions due to increase in operating speeds. Moreover, the fracture mechanics characteristics with respect to the aging effects of wheelset materials have not been clearly studied. In the present study, the following fracture mechanics characterization tests were carried out in accordance with various locations on the wheelset for high-speed train: fracture toughness depending on load rate, fatigue crack growth rate and fatigue thresholds. The results show that the fatigue crack growth rates in accordance to the locations on wheelset were not remarkably different, and the fatigue threshold in the region of the bolt-hole is lower than that in other regions. The fracture toughness depending on load rate data shows that once the downward curve from quasi-static values was reached, subsequent values showed a slow increase with respect to the impact velocity. This means that dynamic fracture toughness should be considered in the design code of the wheelset material.
In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects
Authors: Liu Jian , Feng Xia Ting , Ding Xiu Li , Zhou Huo Ming
Published: March 2009

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.
A Study on Evaluation of Overload Effects on Fatigue Crack Growth
Authors: Kim Ki Sung , Kim Kyung Su , Shim Chun S. , Cho Hyung M.
Published: March 2009

In the fatigue tests of specimens, sufficiently large tensile overload included in cyclic constant amplitude loading causes the retardation in fatigue crack growth. Crack retardation remains for some period of time after the overloading. The number of cycles in the retarded crack growth has been shown to be related to the plastic zone developed due to the overload. The magnitude of the elastic-plastic zone around the crack tip of DENT(Double Edge Notched Tension) specimen after a overloading was measured by ESPI(Electronic Speckle Pattern Interferometry) system. The fatigue crack growth rate also was measured by a traveling microscope. The relationship between the measured magnitude of plastic zone and the crack growth rate was compared with the equations proposed by Wheeler. Crack growth retardation model that was characterized by crack growth length and the size of plastic zone was proposed and compared with test result. From the research, the validity of proposed model is examined on crack growth retardation, and consequently fatigue life.
Thermal Stress and Fatigue Analysis of Exhaust Manifold
Authors: Yoon Sam Son , Lee Keum Oh , Lee Soon Bok , Park K.H.
Published: March 2009

In this study, we investigated the reliability assessment of exhaust manifold used in
thermomechanical condition. Overlay model proposed by Besseling[1] was modified to consider the strain range dependence on elastic limit. By combining geometrical relation in hysteresis loop and temperature dependence of elastic limit with isothermal overlay model, temperature dependent cyclic plasticity model was proposed. Continuous damage model based on isothermal fatigue data was generalized for non-isothermal condition. Finite element analysis and life prediction of exhaust manifold were performed under severe operating conditions.
Solid Solution Strengthening Behavior of 25Cr-20Ni Austenite Stainless Steel
Authors: Park I.D. , Ahn Seok Hwan , Nam Ki Woo
Published: March 2009

The purpose of this paper is to investigate the effect of solid solution strengthening on the high temperature creep strength of STS310J1TB. To make clear the effect of solid solution strengthening, the stress abrupt change test was carried out to observe the instantaneous plastic strain and the stress relaxation test was carried out to investigate the ratio of solid solution strengthening to applied stress. The instantaneous plastic strain was observed in the stress abrupt change test of STS310S, while it was absent in STS310J1TB. This clearly indicates that the dislocations glide viscously in STS310J1TB, while they move in a free flight manner in STS310S. As a result of TEM observation, the dislocation structure of STS310J1TB is more uniform than that of STS310S. From the analysis of the stress relaxation curve, the effective stress to total applied stress was found to be about 16 %.
Application of Roller-Working on Improving the Fatigue Strength of Notched Austenitic Stainless Steel
Authors: Ding J. , Nishida S. , Hattori Nobusuke , Zhang Di , Sun Wen Xian
Published: March 2009

About 90% of steel structure™s failure was induced from the notched parts due to the stress concentration. Therefore it was very important to research how to improve the fatigue property of notched parts when the stainless steel was used as structural material. Rotating bending fatigue test was preformed to investigate the effect of different notch-machining process (Conventional lathe-machining, Combination of lathe-machining and roller-working) on fatigue strength of the
typical austenitic stainless steel SUS304. Fatigue limit of roller-worked specimen was improved to 285% compared to that of lathe-machined specimen. It was found that, work hardening effect induced in roller-working process played an important role to improve the fatigue strength. In addition, the residual compressive stress and the fibriform structure in the specimen surface-layer induced by roller-working were also effective to improve the fatigue strength. Non-propagating fatigue crack was observed in the notch surface of the roller-worked SUS304 for the first time.
Influence of Coarsening Treatment on Fatigue Strength and Fracture Toughness of Al-Si-Mg Alloy Casting
Authors: Tohgo Keiichiro , Oka Masahide
Published: March 2009

In this paper, the influence of the coarsening treatment of eutectic Si particles on fatigue strength and fracture toughness of a peak-aged Al-7%Si-0.4%Mg alloy casting has been investigated. By the coarsening treatment at 808°K for 100 hours, the eutectic Si particles grew to be spherical and were uniformly distributed, but casting defects remained without any changes. On tensile tests, the 0.2% proof stress and tensile strength were almost the same in both as-received material and Si-coarsened material, but the ductility was much higher in the Si-coarsened material
than in the as-received one. Fatigue fracture occurred by crack initiation from the casting defects and succeeding crack growth on both materials, and the fatigue strength of the materials was affected by the size of defects rather than by the coarsening treatment. On the other hand, the fracture toughness was distinctly improved by the coarsening treatment. It is suggested that the improvement of fracture toughness in the Si-coarsened material is attributed to the energy
dissipation due to the damage of Si particles around a crack and the rough fracture path.
Roller Working Effect on Fatigue Strength of Ti-6Al-4V Alloy
Authors: Son S.Y. , Nishida S. , Hattori Nobusuke , Jeong W.T.
Published: March 2009

The fatigue strength have been investigated about the plastic deformed specimens by roller working in Ti-6Al-4V alloy with a notch by 4 kinds of plastic deformation ratio. The plastic deformation values (Δ t) are employed 0.05, 0.1, 0.25 and 0.4 mm on notched specimens of Ti-6Al-4V alloy by roller-working. The hardness test, fatigue test and SEM observation was carried out on non-roller worked specimens and roller-worked specimens at room temperature. Based on the results of these tests, Though the hardness number of roller worked materials are higher than those of non-deformed Ti-6Al-4V alloy, the fatigue limit of roller worked materials becomes deteriorated in spite of roller working. Fatigue fracture had occurred in the non-
deformed area where tensile residual stress exists. From the results of the SEM observation, stepped defect could be notch effect for reducing the fatigue strength of Ti-6Al-4V alloy.
Development of Fatigue Detecting Sensor
Authors: Kobayashi T. , Muragishi O. , Nihei K.
Published: March 2009

A fatigue detecting sensor that enables easy and precise estimation of fatigue damage of machines and structures was developed, based on the crack growth characteristics of metal. The sensor is composed of a metal foil with a single edge notch and a base metal foil. The two metal foils are bonded at the both far ends.
The sensor is attached with an adhesive to the surface of structural member which is subjected to cyclic loads. The fatigue damage of the member is detected as the fatigue crack initiation from the notch tip of the sensor. The fatigue crack growth rate is independent of the crack length. The metal foil of the sensor is given pre-tension, so the sensor has stable crack growth characteristics independent of the average strain. The crack growth length is measured in a certain period after the installation. The length is converted to the fatigue damage of the member during the sampling
period of sensor installation. Since no measuring instrument and signal wiring is necessary, the diagnosis procedure becomes easy and the cost for structural health monitoring could be reduced.
With such small size of the sensor as conventional strain gages, the pin-pointed application of the sensor to the hot spot of structural stress concentration, where is important for the fatigue strength estimation of welded structures, is possible. Therefore, precise fatigue remaining life assessment could be carried out. Sensors with several strain ranges were developed, so application to vast strain range is possible. Even such a small strain range as 1/10000 is able to be detected.
The sensors have been applied to various products like steel bridges, rolling stocks, ships, etc.
Analysis of Creep Crack Growth by Intelligent Phased Array Ultrasonic Inspection
Authors: Jeong C.S. , Lim Byeong Soo
Published: March 2009

At high temperatures typical for service conditions in fossil power plants, the creep fracture is dominated by the formation, growth and coalescence of cavities. Using high temperature pipe materials, P92 and P122, the characteristics of creep crack growth were analyzed in this study according to the cavities. The characteristics of cavities play a critical role in creep crack propagation and load line displacement. The effect of the load line displacement rate(dv/dt) and crack growth rate(da/dt) on the da/dt–Ct relation of creep crack growth was evaluated at different temperatures and Ki(initial stress intensity factor) values. The number of cavities increased with increasing temperature and Ki. The crack growth rate and load line displacement rate increased with the increase in the cavity numbers. The kind and distribution of these internal flaws were investigated by an intelligent phased array ultrasonic method and they were utilized in deriving the relationship with the creep crack growth rate, which will predict the creep characteristics of these materials.
Actuator Performance Degradation of Piezo-Composite Actuator LIPCA under Cyclic Actuation
Authors: Yoon Kwang Joon , Kim Kyu Young , Goo Nam Seo , Park Hyun Chul , Haw J.R.
Published: March 2009

This paper is concerned with the fatigue characteristics of LIPCA (LIghtweight Piezo-Composite Actuator) device system. LIPCA device system is composed of a piezoelectric ceramic layer and fiber reinforced light composite layers, typically a PZT ceramic layer is sandwiched by a top fiber layer with low CTE (coefficient of thermal expansion) and base layers with high CTE. The advantages of the LIPCA design are using the lightweight fiber reinforced plastic layers without compromising the generation of high force and large displacement and to have design flexibility by selecting the fiber direction and the size of prepreg layers. In addition to the lightweight advantage and design flexibility, the proposed device can be manufactured without adhesive layers when we use resin prepreg system. To investigate the degradation of actuation performance of LIPCA due to the repeated fatigue loading, the repeated loading tests up to several million cycle were performed and the actuation displacement for a given excitation voltage was measured during the test. The fatigue characteristics was measured using an actuator test system consisted of an actuator supporting jig, a high voltage actuating power supplier, and a non-contact laser measuring system and evaluated.
Optimization of Testing Method in Comparison with the Coated Composites and Metals by Vibratory Cavitation Test
Authors: Kim Yun Hae , Son Y.J. , Woo B.H. , Bae C.W. , Kim S.M. , Ebara Ryuichiro
Published: March 2009

Cavitation-erosion is a hydrodynamic phenomenon that results in the formation and collapse of vapor bubbles in a liquid. Cavitation damage is encountered in a wide variety of fluid handling machinery and over a broad range of liquid pressures and temperatures. In this study, cavitation damage was investigated by using the piezoelectric vibrator with 20kHz, 50μm to cavity generation apparatus. At the first cavitation test, coated composite material specimens appear to generating the low bubbles due to damping vibration. This study is mainly compared with cavitation test (ASTM G 32) and modified cavitation test. And it is also concerned with phenomenon of cavitation-erosion on the several materials. In order to compare the both test methods, cavitaion weight loss and rate of the several materials in fresh-water and sea-water measured and observed with digital camera.
Failure for Notched Plates of Short Glass Fiber Reinforced Polypropylene under Static and Cyclic Loading
Authors: Yamamoto T. , Takeda H. , Hyakutake Hiizu
Published: March 2009

The validity of the idea of severity near the notch root of notched FRP plates is investigated experimentally. The investigation was accomplished by obtaining experimental data on the static and cyclic loading tests for notched plates of a glass fiber-reinforced polypropylene (GF/PP). To evaluate the damage near the notch root, we measured the luminance distributions by means of a luminance-measuring technique using a CCD camera. The experimental results for the static loading tests show that the configuration and the area of damaged zone near the notch root were
determined by both the maximum elastic stress at the notch root, σmax and notch-root radius ρ. The maximum elastic stress at fracture, σmax,c is governed by the notch-root radius ρ and it is independent of notch depth. The number of loading cycles to fatigue damage initiation is determined by both the σmax and ρ. These experimental results confirm the validity of the failure
criterion in static load and the fatigue failure criterion based on the idea of severity near the notch root.
Fabrication and Properties of Reaction Sintered SiC Based Materials
Authors: Lee Sang Ll , Jin J.O. , Kohyama Akira
Published: March 2009

The characterization of RS-SiC and RS-SiCf/SiC composite materials fabricated by the reaction
sintering process has been investigated, based on the detailed examination of their microstructures.
In this composite system, Tyranno SA SiC fiber and Hi-Nicalon SiC fiber were used as reinforcing
materials. The green bodies for RS-SiC and RS-SiCf/SiC materials were prepared with the complex
matrix slurry of SiC and C particles. The density and the room temperature strength of RS-SiC
material with the starting SiC particles of 0.3 µm showed about 3.1 Mg/m3 and about 520 MPa,
respectively, even if there were large amount of residual silicon (about 19 %). The flexural strength
of Hi-Nicalon/SiC composites greatly decreased at the temperature higher than 1000
Design of Composite Pressure Vessels with Metallic and Plastic Liners
Authors: Kong Cheol Won , Yoon Jong Hoon , Jang Young Soon , Yi Yeong Moo
Published: March 2009

Lightweight composite pressure vessels were designed with thin metallic and plastic liners. This paper discusses the structural design, the fabrication, and the experiment of the composite pressure vessels with metallic and plastic liners. Both liners were non-load sharing types, therefore only the composite sustained an internal pressure. The liner provided a gas seal. The materials of the liners were Al 6061 and CLPE (cross linked polyethylene) each. The composite pressure vessels were winded using T700 carbon/epoxy on the liners. The multiple cure cycles prevented the aluminum liner from losing a circular shape and the concentrated force at the metallic boss was spread to the composite fiber by the boss design. In case of the plastic liner, the boss design considered that CLPE had no adhesive property. Although the plastic liner has the advantage for the elongation,
some environmental tests for temperature and vibration effects are needed in order to use in space applications.
Numerical Simulation on Failure Patterns of Rock Discs and Rings Subject to Diametral Line Loads
Authors: Zhu Wan Cheng , Chau K.T. , Tang Chun An
Published: March 2009

Brazilian test is a standardized test for measuring indirect tensile strength of rock and concrete disc (or cylinder). Similar test called indirect tensile test has also been used for other geomaterials. Although splitting of the disc into two halves is the expected failure mode, other rupture modes had also been observed. More importantly, the splitting tensile strength of rock can vary significantly with the specimen geometry and loading condition. In this study, a numerical code called RFPA2D (abbreviated from Rock Failure Process Analysis) is used to simulate the failure process of disc and ring specimens subject to Brazilian test. The failure patterns and splitting tensile strengths of specimens with different size and loading-strip-width are simulated and compared with existing experimental results. In addition, two distinct failure patterns observed in ring tests have been
simulated using RFPA2D and thus this verifies the applicability of RFPA2D in simulating rock failure process under static loads.
Study on Stability and Anchoring Effect of Jointed Rock Mass of An Underground Powerhouse
Authors: Li S.C. , Chen Wei Zhong , Zhu Wei Shen , Qiu X.B. , Yang Chien Hsin
Published: March 2009

This present paper adopts a constitutive model for elastic damage of intermittently jointed rock mass, damage-evolution equations and a supporting model of damaged rock-bolt bar(DRBB) element to simulate effect of reinforcement. The results have indicated that the above method well describes the progressive failure process of the surrounding rock mass and the anchorage effect. The theoretical achievements are of referential value to designers.
Numerical Studies of the Influence of Heterogeneity on Rock Failure with Pre-Existing Crack in Uniaxial Compression
Authors: Huang Ming Li , Wong R.H.C. , Wang S.Y. , Tang Chun An , Jaio R.M.
Published: March 2009

This study is to evaluate the effect of the heterogeneity on the failure processes and strength characterization of brittle rock containing the single pre-existing crack (or flaw) under uniaxial compression loadings. The numerical simulation reproduces the evolution of the stress and strain fields in flaw propagation process, the mode of acoustic emission related to the heterogeneity of rock and the phenomenon related to discontinuous. It is shown that the lower the value of the homogeneous index, the more influence of local variation on the propagation process of the pre-existing flaw, and there occurs more randomly distributed microfractures throughout the specimen. Studying the details of macrofracture formation in relatively homogeneous specimens, it is interesting to find that there exists a 'constant jump' propagation pattern of the wing crack, which is responsible for the formation of the pre-existing flaw. The numerical results also demonstrate that the stress-strain relation and strength characterization depends strongly on the heterogeneity of the specimen. The heterogeneous rock has a gentler post-peak behavior and lower strength, while the more homogeneous specimen has a higher strength, accordingly, the curve
becomes more linear and the strength loss is also rapidly.
Displacement Back Analysis Research on Bolt-Grouting Supporting Parameter of Rock Mass in Jointed Rock Roadway
Authors: Zhang Le Wen , Li Shu Chen , Li Shu Cai
Published: March 2009

The method of bolt-grouting supporting, grouting into surrounding rock mass by bolts in jointed rock mass roadway, is obtained wide application. However, it is difficult to determine rock mass parameter of bolt-grouting supporting. This paper begins with the displacement, which is measured easily in practice. The method of back analysis is adopted to calculate the equivalent mechanics parameters of bolt-grouting rock mass. In process of back analysis three mechanics models is supposed which are homogeneous elastic model, inhomogeneous elastic model and elastic-plastic
model and corresponding algorithm is established. What's more, this paper discusses the stability of inverse algorithm and copes the problem of back analysis parameter probably instable with QR decomposed algorithm and singular value decomposed algorithm, which will be a theoretical base to determine the mechanics parameter of bolt-grouting supporting rock mass and to estimate the surrounding rock stability. In a word, the method is established to estimate mechanics parameters of bolt-grouting jointed surrounding rock mass, and some significant results are obtained, which are of reference for actual project.
Image Reconstruction and Analysis of Three-Dimensional Fracture Surfaces Based on the Stereo Matching Method
Authors: Tanaka M. , Kimura Y. , Kayama A. , Chouanine L. , Kato Reiko , Taguchi J.
Published: March 2009

A computer program of the fractal analysis by the box-counting method was developed for the estimation of the fractal dimension of the three-dimensional fracture surface reconstructed by the stereo matching method. The image reconstruction and fractal analysis were then made on the fracture surfaces of
materials created by different mechanisms. There was a correlation between the fractal dimension of the three-dimensional fracture surface and the fractal dimensions evaluated by other methods on ceramics and metals. The effects of microstructures on the fractal dimension were also experimentally discussed.
Application of Fine Blanking to the Manufacture of a Sprocket with Stainless Steel Sheet
Authors: Seo Y.H. , Kim Byoung Kee , Son H.D.
Published: March 2009

Wire cutting(EDM) or blanking is used to made workpieces from sheet metal. Wire EDM provides a relatively simple method for making holes of any desired cross section in material. But EDM requires a lot of working time and the high unit cost of production. In conventional blanking, for the production of precision devices or assemblies, it is always necessary that at least two, but generally more, secondary operations are required per piece part. Using the fine blanking process, a precise finished part with inner and outer forms clearly sheared over the whole material thickness are produced in one single operation. In this study an attempt is made to manufacture a sprocket with fine blanking process. The sprocket is parts for the tape feeder of surface mount system in electronic parts. First, a change of the existing design is made in a sprocket. The materials selected are three kinds of stainless steel, SUS304, SUS316 and SUS430. And the mechanical properties are
investigated through the tensile test. After fine blanking, hardness and precision are examined with hardness test and 3-dimensional coordinate measuring for samples. The results of investigations of fine-blanking process with the help of FEM code, DEFORM 2D, are presented. For the simulation, SUS304 and SUS316 are used as materials. The damage model of Cockroft and Latham is used to calculate damage. Die-roll height, die-roll width, burnish zone and fracture zone from the fine blanking simulation are investigated in comparison with them of samples. And the applied force at each part of fine-blanking die is estimated with load-stroke diagram.
The Study on Effects of Thermal Aging of Dissimilar Weld Zone in a Primary Reactor Cooling System
Authors: Kwon Jae Do , Woo Seung Wan , Choi Y.H.
Published: March 2009

In a primary reactor cooling system(RCS), a dissimilar weld zone exists between austenitic-ferritic duplex cast stainless steel(CF8M) in a pipe and low-alloy steel(SA508 cl.3) in a nozzle. Thermal aging is observed in CF8M as the RCS is exposed for a long period of time to a reactor operating temperature between 290 and 330°C, while no effect is observed in SA508 cl.3. An investigation of the effect of thermal aging on the various mechanical properties of the dissimilar weld zone is required. The purpose of the present investigation is to find the effect of thermal aging on the dissimilar weld zone. The specimens are prepared by an artificially accelerated aging technique maintained for 100, 300, 900, 1800 and 3600 hrs at 430°C, respectively. The various mechanical tests for the dissimilar weld zone are performed for virgin and aged specimens.
The Role of Constraint and Warm Pre-Stress on Brittle Fracture in Ferritic Steels
Authors: Mirzaee-Sisan A. , Hadidi-Moud Saeid , Truman Christopher E. , Smith David John
Published: March 2009

This paper presents the results of an experimental and numerical study carried out to investigate the effect of warm pre-stressing on cleavage fracture in ferritic steels using cracked and notched specimens. It is shown that the local approach based on Weibull theory predicts the increase in toughness following warm pre-stressing in highly constrained geometries. The observed effect of pre-loading in low constraint specimens such as round notched bars is less. The local approach could not predict the differences and it is suggested that the variation of triaxiality factor, the ratio of hydrostatic stress to Von Mises, in the plastic zone, is a contributing factor.
Effect of Constraint on the Initiation of Ductile Fracture in Shear Loading
Authors: Ayatollahi Majid R. , Smith David John , Pavier M.J.
Published: March 2009

Research studies for mode I cracks have shown that fracture toughness or the critical value of J for fracture initiation, Jcrit is not merely a material property but depends also on the geometry and loading configurations. The geometry dependency of fracture toughness can be attributed to the effect of the crack tip constraint. In this paper, the constraint effect is studies for the initiation stage in mode II ductile crack growth. Two major mechanisms of ductile fracture: 'void growth and coalescence' and 'shear band localization and de-cohesion' are considered. A boundary layer model is simulated using the finite element method and the effect of far-filed T-stress on the relevant stress parameters near the crack tip is studied. It is shown that the initiation of the ductile crack growth in mode II is influenced significantly by T for the mechanism of void growth and coalescence and is insensitive to T for the mechanism of shear localisation and de-cohesion.
Effects of Impact Angle on Cone Crack Formation in Impact-Loaded Soda-Lime Glass
Authors: Kim Moon Saeng , Shin Hyung Seop , Lee Hyeon Chul , Kim Ho Jong
Published: March 2009

In order to investigate the possibility of punching process of brittle material by ball impact, effects of impact angle on cone crack formation in impact-loaded soda-lime glass were evaluated experimentally. Evaluated were also contact area between specimen and sealing, and the optimal condition for cone crack formation in glass plates by impact with small steel balls. It has been found that lateral and radial cracks gradually developed asymmetrically. However, the perfect cone cracks
were found to develop almost symmetrically. As the impact angle increased, the growth rate of cone cracks decreased. Regardless of the impact angle, the PMMA sealing was more effective for perfect cone formation than Aluminum and Polyurethane sealing. Thus, the application for industrial technology for hole (or nozzle) punching process of the brittle materials is expected to be feasible,
based upon proper selection of sealing materials.
The Structural Impact Characteristics of Indonesian Railway Vehicle
Authors: Puja Ign Wiratmaja , Hardono T. , Khalid  , Adziman M.F.
Published: March 2009

The Indonesian railway transportation has adventages in term of capacity, efficiency, trafic, and safety compared to the other types of land transportations. At present, the Indonesian Railway Company has 519 locomotives, and 1643 passenger cars, that transport about 184 million man-trip each year[1,2]. Unfortunately, the rate of train collisions in Indonesian railway system was very
high. In the last ten years, 2352 train accidents have happened which claimed 997 lives and left 2638 people injured. The record shows that 110 of those accidents were train to train collisions[1]. This paper consider the structural impact behavior of Indonesian passenger railway car subject to collision forces. This characteristic is very important parameter for passenger protection during the course of collision[3-5]. The vehicle structure should be able to absorb the huge impact energy or impact force to ensure the passenger safety[6-9]. The impact energy of cars-train is evaluated using the principle of multibody dynamics[10,11]. The vehicle structure under impact load is analyzed using the finite element method. The principal of symmetry is adopted, so the collision scene could be simulated as collision between the vehicle with a rigid wall. The analysis result shows that the structure is collapse at the passenger area (saloon) which is in agreement with the real collision.
Modification is proposed to protect the passenger area by introducing crush zone area and impact energy absorber.
Failure Behavior of Anodized Coating-Magnesium Alloy Substrate Structures
Authors: Wang Xi Shu , Feng Xi Qiao , Guo Xing Wu
Published: March 2009

This work focuses on the damage mechanisms and the resulting failure behavior of structures made of anodized coatings on magnesium alloy substrates. The failure of anodized coatings of about 30µm thickness on AZ91D substrates was investigated under three-points bending loading with online scanning electron microscope (SEM) observations. The obtained SEM images show that void nucleation and crack initiation occurs mainly at sites near the coating-substrate interface, and the evolutionary microcracking damage diffuses from the interface to the coating surface and also to the bulk substrate with the increasing in loading.
Prevention of Delamination during Drilling of Composite Material Using Vibration
Authors: Aoki Shigeru , Nishimura Toshiyasu
Published: March 2009

Prevention method of delamination at adhesive layer during drilling of composite material using vibration is examined. First, this method is examined experimentally. As vibrational load, relatively low frequency vibration and ultrasonic vibration are used. It is concluded occurrence of delamination is less when vibration is used during drilling. Next, experimental results are examined by analytical method. Adhesive layer is assumed to be damping component. Condition of occurrence of delamination is proposed.
Effect of the Groove Shape of Ultra Thick Box-Column with Center Segregation under High Heat Input for Corner Welding
Authors: Kwon Young Doo , Choi W.K. , Kwon Hyun Wook , Choo H.S.
Published: March 2009

The time-dependent distributions of temperature and stresses in a box-column welded from ultra thick plates with a center segregation were analyzed using the commercial finite element package SYSWELD+ for several types and angles of groove. The welding method used in the current study was SAW(submerged arc welding), which was initially simulated using the commercial finite element package MSC/MARC, combined with a user-defined subroutine, to identify the weld thermal cycle. The major points of investigation were the optimum type and angle of groove that would minimize the weld stress, especially at the center segregation. A nonlinear transient heat transfer analysis was accomplished. The thermal properties, i.e. conductivity and specific heat, were found to be temperature dependent, plus the effects arising from a phase change, convection, and radiation were also taken into account.
Development of a Micro Gyroscope Using Epitaxial Polysilicon and Its Performance Test
Authors: Sung Woon Tahk , Lim Hyung Taek , Kang Tae Sam , Lee Jang Gyu , Lee Young Jae
Published: March 2009

This paper presents a design and performance tests of in-plane gimbal-structured Z-axis gyroscope. The device is manufactured by conventional surface micro machining process using 15µm-thickness epitaxially grown polysilicon. The total size of the device is 4.8mm x 4.8mm in area including 1mm x 1mm core gyro structure and pads for wire bonding. It is designed as two-gimbaled structure which separates inner and outer gimbals. This leads two nearly identical modes of gyroscope, i.e. driving and sensing mode, to mechanically decoupled ones, resulting in enhanced performance. Experiments are accomplished through frequency analysis and dynamic tests using a detection circuit, a vacuum chamber and a rate table. Through experiments, it is confirmed that the designed gyroscope has 0.003 deg/sec resolution, 0.00095 deg/sec/ Hz noise equivalent density, 0.57 % FSO nonlinearity error and 0.02 deg/sec bias stability.
Thermo-Mechanical Stress in Passivated Al-0.5%Cu Thin Films
Authors: Jeon I. , Park Yong Bum , Inoue Hisahiro , Kishimoto Kikuo
Published: March 2009

The volume-averaged hydrostatic parts of thermo-mechanical stresses in the metal interconnect line determined by XRD method and finite element method are compared with each other. Two typical shapes of passivated Al-0.5%Cu thin film with SiN or FOx(Flowable Oxide) are selected for this study. For the numerical calculation, the stress concentration effect around the edge of Al-Cu thin film and elastic-plastic behavior of the film following its hardening rule are considered. For the
stress obtained by XRD, the experimental results of Park and Jeon[Microelectron. Eng., 69 (2003) p.26] are introduced. A good agreement is found between the volume-averaged hydrostatic stresses obtained from each method.
Study of Thermo-Rheology Characters of Rock under the Uni-Axial Compression
Authors: Wang Chong Ge , Song Zhao Qing , Chen Wei Zhong , Liu Quan Sheng , Yang Chien Hsin
Published: March 2009

This paper introduces temperature effect to rock model. It sets up a thermo-visco-elastic-plastic rock model. Based on the rock model which consists of spring, dashpot and plastic elements under the condition of un-axial compression, the behaviors of the thermo-visco-elastic-plastic in rock are discussed, and the equations of the constitutive, creep, unload and relaxation have been obtained. This model can reflect the rock or rock mass average thermo-rheology character. Meanwhile, this study gives a explanation of the significances of this kind of model in
the practical use.
Three-Dimensional Elastic-Plastic Finite Element Analysis of Biaxially Loaded Cracked Plates
Authors: Chung Kwang Hwa , Kim J.S. , Kim J.S. , Kim Young Jin
Published: March 2009

Based on detailed two-dimensional (2-D) and three-dimensional (3-D) finite element (FE)analyses, this paper attempts to quantify in-plane and out-of-plane constraint effects on elastic-plastic J and cracked tip stresses for biaxially loaded plate with a through-thickness crack and semi-elliptical surface crack. It is found that the reference stress based approach for uniaxial loading can be applied to estimate J under biaxial loading, provided that the limit load specific to biaxial loading is used, implying that quantification of the biaxiality effect on the limit load is important.
Investigation on the effect of biaxiality on the limit load suggests that for relatively thin plates with small cracks, in particular with semi-elliptical surface cracks, the effect of biaxiality on the limit load can be neglected, and thus elastic-plastic J for a biaxially loaded plate could be estimated, assuming that such plate is subject to uniaxial load. Regarding the effect of biaxiality on crack tip stress triaxiality, it is found that such effect is more pronounced for a thicker plate. For plates with semi-elliptical surface cracks, the crack aspect ratio is found to be more important than the relative crack depth, and the effect of biaxiality on crack tip stress triaxiality is found to be more
pronounced near the surface points along the crack front.