bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Analysis of a Composite Nuclear Fuel Waste Disposal Container
Authors: Garroni James D. , Crosthwaite J. Les 
Published: July 2023

Abstract
A composite container for the retention and disposal of used CANDU™ nuclear fuel was structurally analyzed. The design employs an inner steel vessel for support against external pressure and a close-fitting outer copper vessel for corrosion resistance. The container is deposited in an underground disposal vault in granitic rock and is surrounded by a clay-based buffer that swells when contacted by groundwater. It must withstand the swelling pressure of the buffer plus the hydrostatic pressure of the groundwater at a minimum 500-m depth. The case was analyzed in which a small manufacturing defect penetrates the copper shell, allowing groundwater to seep between the vessels and gradually convert the steel of the inner vessel to magnetite. Because the specific volume of magnetite is approximately twice that of steel, the outer surface of the steel vessel progressively swells while the remaining (uncorroded) shell thins. Outward deformation of the copper vessel is resisted by the buffer and surrounding rock, therefore pressure on the steel vessel gradually increases as it corrodes.
The finite element code, ANSYS, was used to predict the minimum corrosion that would produce plastic collapse of the steel vessel. Knowledge of the rate of conversion of steel to magnetite under disposal-vault conditions could then allow an estimate of the time-to-collapse following the initial ingress of groundwater.
Finite Element Analysis (FEA) of Motor Operated Valves (MOV) Disc Tabs Subjected to Valve Opening Loads
Authors: Rao K. R. , Chism J. Wesley 
Published: July 2023

Abstract
Nuclear power plants valve testing programs require determination of opening loads for certain motor operated valves (MOV). The opening loads must be evaluated to determine if the valve components are within acceptable stress limits. These loads may cause the valve internals to appear overstressed when conventional linear hand calculations are used to determine valve component stresses. Finite element analyses (FEA) methods have been developed to permit more accurate determination of component stresses. This paper describes the FEA methods used to analyze valve components. Acceptance criteria using FEA methods which are not explicitly addressed in the ASME Code are explained in this paper. Using a Case Study Example of a Disc Tab of a motor operated valve (MOV), it is demonstrated how the stated acceptance criteria can be satisfied.
Approximate Evaluation Method for Crack Growth Rates Under Repeated Large Plastic Deformation
Authors: Igi Satoshi , Hidaka Kentaro , Kawahara Masanori 
Published: July 2023

Abstract
Many countries have suffered from large earthquakes in the past few decades. Extensive efforts are required to estimate the fracture behavior under cyclic plastic strains in steel components so as to prevent or minimize fatal accidents. Crack growth rates under cyclic loads have been generally analyzed by Paris’ law by using a linear elastic fracture mechanics concept, “ΔK”, stress intensity factor range. But, this approach cannot be valid in the domain of large plastic deformation. An alternative approach could be developed by substituting J-integral or crack tip opening displacement for stress intensity factor. However, this is yet not very easy to apply in real complicated structural components, as it takes much excessive computational time for the calculation of the governing fracture parameters.
The present paper proposes an approximate method to evaluate crack growth rates under repeated large plastic deformation by using an easier formulation based on an approximate analysis of fracture parameters. Crack growth experiments have been conducted under cyclic axial plastic loadings in order to verify the validity of the proposed formula. Experimental results showed fairly good agreement to the proposed formula. Discussion is as well directed to the change in the feature of fracture surfaces during growth.
An Analysis of the Two Bar Ratcheting Behavior Using the Viscoplasticity Theory Based on Overstress (VBO)
Authors: Nakamura Toshiya , Krempl Erhard 
Published: July 2023

Abstract
The ratcheting behavior of the “unsymmetric two bar system” was investigated by numerical experiments. The two bars are restrained to the same length and are subjected to a constant load. One bar sees cyclic temperature variations while the other bar is kept at constant temperature. The material models employed are rate-independent plasticity (kinematic hardening) and the Viscoplasticity Theory based on Overstress (VBO) matched to represent the cyclic neutral 6061 T6 Aluminum alloy elastic and inelastic deformation behavior. For simplicity temperature independent material properties were assumed. Numerical analyses were performed to investigate the effects of rate of thermal loading and temperature range.
Elastic-inelastic shakedown is ultimately achieved due to work hardening There is a strain range increase until it reaches a steady value. Kinematic hardening and VBO predict almost the same strain range which for the case of VBO is nearly rate independent. The behavior for both material models is very different for the mean strain. For VBO, the number of cycles to shakedown is rate-dependent and is considerably larger than for kinematic hardening. Finally, the steady state mean strain and strain range are computed directly for VBO.
A Computational Engine for the Nonlinear, Transient Response of Preloaded Structures
Authors: Kulak R. F. , Pfeiffer P. A. 
Published: July 2023

Abstract
The transient loading of mechanical components and structures is usually performed with the assumption that there are no preloads applied to them since preloads are usually small and can be neglected. However, for certain structures used in the nuclear power industry, the preloads are significant and must be considered in the transient analysis. Two examples of these types of structures are prestressed concrete containments and inter-compartment locks, which respond with both geometric and material nonlinearities during transient loadings. An efficient computational engine is presented in this paper for the solution of these types of problems. An example is presented to illustrate the algorithm. A preloaded platen, which is part of an inter-compartment lock, is subjected to an impulsive load. The resulting transient response of the system is presented.
Demonstration of the Electric Controlled Pneumatic Brakes on the Union Pacific Railroad
Authors: Cartwright Robert A. , McConnell David S. 
Published: July 2023

Abstract
The purpose of the demonstration was to evaluate what degree Union Pacific Railroad should support further development of Electronic Controlled Pneumatic (ECP) brakes, by investigating:
Crew Acceptance
Equipment Reliability
Train Performance
Possibility of “wire line” Distributed Power.
The results obtained concerning these issues are discussed along with Union Pacific’s philosophy concerning this technology.
Curved Plate Wheel Design for a Commuter Railroad’s Reverse Dish 32″ Car Wheel
Authors: Rusin Thomas M. , Coughlin John M. , Damergis George 
Published: July 2023

Abstract
An improved curve plate wheel is presented for the 32″ reverse dish wheel which will reduce the incidences of thermally cracked wheels. The finite element method (FEM) design process, for the first time, employed elastic-plastic methodology and incorporated the residual stress from the manufacturing process. Dynamometer measurements of the thermal and mechanical stresses of the straight plate version of the wheel are compared to FEM thermal and thermal elastic-plastic predictions, for high speed stops. Finite element predictions of the thermal and mechanical stresses for the curve plate wheel are compared to those of the straight plate wheel.
Three-Dimensional Penetration Modelling of Composite Plates
Authors: Chen J. K. , Beraun J. E. 
Published: July 2023

Abstract
The smoothed particle hydrodynamics (SPH) technique in conjunction with the macro-mechanics approach for fiber composites was developed to predict impact damage of composite structures. For investigating the detailed perforation process and damage progression, 3-D simulations of a graphite/epoxy composite laminate struck by a steel projectile were performed. The predicted damage in the composite target agrees well qualitatively with the experimental results. This study has demonstrated that SPH can be a robust and viable analytical tool for predicting the accurate response of fiber-reinforced composite structures subjected to high-velocity impact.
Damage Growth in Stitched Graphite/Epoxy Laminates Under Mode I Fracture and Compression Loading
Authors: Sharma Suresh K. , Sankar Bhavani V. 
Published: July 2023

Abstract
Published studies have reported outstanding improvements in Mode I fracture toughness and compression after impact (CAI) strength of fibrous composites due to through-the-thickness (z-fiber) reinforcement. One of the methods of through-the-thickness reinforcement successfully experimented by the authors is stitching of textile composites. Our results have shown improvements of about 30 times higher Mode I fracture toughness as characterized by critical strain energy release rate (GIc) and up to 400% increase in the CAI strength over the unstitched textile composites. In this paper we illustrate the damage growth and its underlying mechanisms in the case of stitched composites as observed in our studies. The role and interplay of starter crack, first line of stitches, needle and bobbin yarns, type of stitch lock, stitch density and other processing parameters are discussed. Double Cantilever Beam (DCB) tests were conducted on 24 ply graphite/epoxy (AS4/3501-6) uniweave textile laminates stitched with different yarns and densities to measure Mode I fracture toughness. 48 ply AS4/3501-6 uniweave textile laminates with different simulated impact damage were tested in compression to measure CAI strength. In addition, the effect of stitching on thinner 16 ply AS4/3501-6 plain weave textile laminates was studied where the gains in CAI strength, though noticeable, are much less than for the thicker laminates.
Matrix Cracking With Irregular Fracture Fronts as Observed in Fiber Reinforced Ceramic Composites
Authors: Hu Kai X. , Yen Chao-pin , Wyatt Karl W. 
Published: July 2023

Abstract
As a result of matrix cracking in fiber reinforced composites, fracture planforms assume a wide variation of profiles due to the fact that fiber bridging strongly affects the behavior of local crack fronts. This observation raises the question on the legitimacy of commonly used penny-shaped crack solutions when applied to fiber reinforced composites. Accordingly, investigation of the effects of fracture front profiles on mechanical responses is the thrust of this paper. We start with the solution of a penny-shaped crack in a unidirectional, fiber reinforced composite, which demonstrates necessarity of considering wavy fracture fronts in fiber reinforced composites. A theoretical framework for fiber reinforced composites with irregular fracture fronts due to matrix cracking is then established via a micromechanics model. The difference between small crack-size matrix cracking and large crack-size matrix cracking is investigated in detail. It is shown that the bridging effect is insignificant when matrix crack size is small and solution of effective property are obtained using Mori-Tanaka’s method by treating cracks and reinforcing fibers as distinct, but interacting phases. When the crack size becomes large, the bridging effects has to be taken into consideration. With bridging tractions obtained in consistency with the micromechanics solution, and corresponding crack energy backed out, the effective properties are obtained through a modification of standard Mori-Tanaka’s treatment of multi-phase composites. Analytical solutions show that the generalization of a crack density of a penny-shaped planform is insufficient in describing the effective responses of fiber-reinforced composites with matrix cracking. Approximate solutions that account for the effects of the irregularity of crack planforms are given in closed forms for several cases, including rectangle, polygon, rhombus, cross and the wavy fracture front.
Plane Stress Dynamic Crack Growth Along a Ductile/Rigid Interface
Authors: Deng Xiaomin 
Published: July 2023

Abstract
Dynamic crack growth along elastic bimaterial interfaces have been studied extensively in the past decade by many researchers. In contrast, studies of dynamic interfacial fracture under elastic-plastic conditions are still very limited. In this presentation, the results of an analytic investigation of the asymptotic stress and deformation fields at the tip of a dynamically growing interface crack between a ductile material and a rigid substrate under plane stress conditions will be reported. The ductile material is taken to be ideally plastic and obey the J2 flow theory of plasticity. Under steady-state conditions, the asymptotic structure of the crack-tip stress, velocity and strain fields has been obtained. The study reveals that two types of crack-tip sectors exist, namely uniform and nonuniform plastic sectors and that the stress, strain and velocity fields are bounded in all sectors. In a uniform sector, the rectangular Cartesian components of the stress, strain and velocity fields are constant, and there is no plastic strain accumulation. In a nonuniform sector, the stress, strain and velocity components at a point depend on the angular position of the point in the crack-tip polar coordinate system and are governed by a system of simultaneous ordinary differential equations. This is a sector where plastic strains can accumulate. A general crack-tip sector assembly has been obtained for a practical range of crack growth speeds. Several nontrivial families of admissible solutions of the crack-tip fields based on this general assembly of uniform and nonuniform crack-tip sectors will be presented and discussed. Finally, comparisons with corresponding plane strain solutions (Deng, 1993 a) will be made.
Comparison of Physical Aging Effects on the Tension and Compression Creep of the IM7/K3B Composite
Authors: Gates Thomas S. , Veazie David R. , Brinson L. Catherine 
Published: July 2023

Abstract
Experimental and analytical methods were used to investigate the similarities and differences of the effects of physical aging on creep compliance of IM7/K3B composite loaded in tension and compression. Two matrix dominated loading modes, shear and transverse, were investigated for two load cases, tension and compression. The tests, run over a range of sub-glass transition temperatures, provided material constants, material master curves and aging related parameters. Comparing results from the short-term data indicated that although trends in the data with respect to aging time and aging temperature are similar, differences exist due to load direction and mode. An analytical model was used for predicting long-term behavior using short-term data as input. This model worked equally as well for the tension or compression loaded cases and provided more accurate long term predictions for the shear mode as compared to the transverse mode.
Comparison of Effectiveness of Shape Memory Alloy and Composite Stiffeners in Stability Problems of Composite Shells and Plates
Authors: Birman Victor 
Published: July 2023

Abstract
The effects of composite and shape memory alloy stiffeners on stability of composite cylindrical shells and rectangular plates subjected to a compressive load are compared. The governing equations for reinforced cylindrical shells are developed based on the Love first approximation theory and smeared stiffeners technique. It is shown that composite stiffeners are more efficient in cylindrical shells, while shape memory alloy stiffeners may be preferable in flat plates or in long shallow shells. It is also proven that shape memory alloy stiffeners increase the upper and lower buckling loads of cylindrical shells modeled as single-degree-of-freedom systems by the same amount.
Photodeformation and Light-Temperature-Piezoelectric Coupling of Optical Actuators: Part 2 — Vibration Control
Authors: Liu B. , Tzou H. S. 
Published: July 2023

Abstract
Non-contact optical actuators driven by high-energy lights are investigated and applications to active vibration control of plates are demonstrated in this study. An optical servo control system coupled with a rectangular plate is proposed. Active vibration control and modal control effectiveness of the rectangular plate are evaluated. The proportional velocity feedback is compared with the Lyapunov control. Experimentally calibrated simulation results show that the optical actuators are effective in vibration control and the highest frequency of controllable vibration can achieve several hundred Hertz. The time histories also indicate that the Lyapunov control is more effective as compared with the proportional feedback control.
Cracking in Ferroelectric and Antiferroelectric Ceramic Multilayer Actuators
Authors: Gong Xiaoyan , Yu Honghui , Suo Zhigang , McMeeking Robert M. 
Published: July 2023

Abstract
This paper models cracking in the poling process of a ferroelectric actuator and the operation of an antiferroelectric actuator. In each case, domain switching or phase transition produces large electric displacement and strain. Around an internal electrode edge, such strain causes cracking, which, in turn, is a precursor to electrical breakdown. We model domain switching or phase transition by large increases of both the electric displacement and field induced strain under a small change in the electric field near the coercive field. Ignoring the stress contribution to the electric field, we solve the electric field around the internal electrode edge for nonlinear electric field and electric displacement relations. We then solve a standard elastic residual strain problem to determine the stresses in the structure. Fracture mechanics is then used to determine the cracking conditions in actuators. We find that a critical thickness exists, below which cracking will not occur. This agrees with the prediction of Hao et al (1996), and Gong and Suo (1996).
Combustors for Micro-Gas Turbine Engines
Authors: Waitz Ian A. , Gauba Gautam , Tzeng Yang-Sheng 
Published: July 2023

Abstract
The development of a hydrogen-air microcombustor is described. The combustor is intended for use in a 1 mm2 inlet area, micro-gas turbine engine. While the size of the device poses several difficulties, it also provides new and unique opportunities. The combustion concept investigated is based upon introducing hydrogen and premixing it with air upstream of the combustor. The wide flammability limits of hydrogen-air mixtures and the use of refractory ceramics enable combustion at lean conditions, obviating the need for both a combustor dilution zone and combustor wall cooling. The entire combustion process is carried out at temperatures below the limitations set by material properties, resulting in a significant reduction of complexity when compared to larger-scale gas turbine combustors. A feasibility study with initial design analyses is presented, followed by preliminary experimental results from a 1:1 scale silicon carbide microcombustor. Issues of flame stability, heat transfer, ignition and mixing are addressed. A discussion of requirements for catalytic processes for hydrocarbon fuels is also presented.
Control of Roll Moment by MEMS
Authors: Lee Gwo-Bin , Ho Chin-Ming , Jiang Fukang , Liu Chang , Tsao Tom , Tai Yu-Chong , Scheuer Fabien 
Published: July 2023

Abstract
In this paper, we will illustrate that the motion of a delta wing can be controlled by actuators fabricated by micromachining technology, if the size of the micro-actuator matches the thickness of the thin boundary layer at the leading edge of the delta wing. This match provides a coupling between the micro actuator and the flow instability which serves as an effective amplifier of the artificial disturbances. The distributed micro-actuators perturb the flow and break the symmetry of the two leading edge separation vortices such that a torque is obtained.
Vehicle Rollover: Assessing the Relative Importance of Risk Factors With Crash Scenario Analysis
Authors: Donelson Alan C. , Ramachandran Karuna , Davis Martin S. 
Published: July 2023

Abstract
Most problems that would benefit from motor vehicle risk analysis involve questions about the importance of design features or other characteristics of vehicles relative to factors related to drivers, driving environments, and types of collisions. Outcomes of motor vehicle accidents result from interactions among several or more pre-crash and at-crash factors. The inherent complexity of motor vehicle accidents often defeats traditional approaches to multivariate regression analysis. This paper introduces a new technique called crash scenario analysis. Rather than treating many causal factors as discrete variables, combinations of factors define crash scenarios. A single variable (scenario risk) measures the likelihood of crash outcomes for vehicles involved in each unique scenario. The authors applied crash scenario analysis to vehicle rollover and used logistic regression to estimate the importance of vehicular factors relative to scenario risk. Findings indicated that scenario risk was a much stronger predictor of rollover in fatal crashes than vehicle static stability factor (T/2H).
The Nuisance Fire Problem With Acetylene B Cylinders
Authors: Tudor Andrew H. , Mniszewski Kim R. 
Published: July 2023

Abstract
On November 19, 1992, a three-story, twenty-two unit condominium project in the Los Angeles area was consumed by fire. The structure, in the framing stages of construction, burnt to the ground. Several adjoining structures sustained varying degrees of fire damage. The fire was caused by a golf ball-sized fire emanating from the threaded connection in a plumber’s air/acetylene piping system, caused by a leak at the threaded connection between the acetylene B tank and the regulator. Unfortunately, a small nuisance fire in this area can quickly become a dangerous and unmanageable fire upon operation of the (safety) fusible plug, which is proximate to this connection.
Results of literature searches and reviews of appropriate industry standards indicate that this valve site is prone to these “nuisance” fires. Analysis of other sizes of acetylene tanks indicate a design philosophy significantly different from that used for the subject B tank. These design differences have profound safety implications. Results of analysis and testing of conventional acetylene B tanks have demonstrated inherent defects and have identified existing designs that eliminate these defects. A complete analysis addressing human factors, standards, mechanical, and thermal design issues is presented. Testing further supported and validated the analytical models where necessary.
The ultimate objective is to design an acetylene tank which can sustain human error, allow for a means to eliminate or control the nuisance fire and can demonstrate superior fire performance. An alternative design was identified that achieves this. Changes to DOT and CGA standards regarding such tanks are recommended.