Failure Analysis of Induction Hardened Automotive Axles

Rollover accidents in light trucks and cars involving an axle failure frequently raise the question of whether the axle broke causing the rollover or did the axle break as a result of the rollover. Axles in these vehicles are induction hardened medium carbon steel. Bearings ride directly on the axles. This article provides a fractography/fracture mechanic approach to making the determination of when the axle failed. Full scale tests on axle assemblies and suspensions provided data for fracture toughness in the induction hardened outer case on the axle. These tests also demonstrated that roller bearing indentions on the axle journal, cross pin indentation on the end of the axle, and axle bending can be accounted for by spring energy release following axle failure. Pre-existing cracks in the induction hardened axle are small and are often difficult to see without a microscope. The pre-existing crack morphology was intergranular fracture in the axles studied. An estimate of the force required to cause the axle fracture can be made using the measured crack size, fracture toughness determined from these tests, and linear elastic fracture mechanics. The axle can be reliably said to have failed prior to rollover if the estimated force for failure is equal to or less than forces imposed on the axle during events leading to the rollover.     

Breakage detection of small-diameter tap using vision system in high-speed tapping machine with open architecture controller

In this research, a vision system for detecting breakages of small-diameter taps, which are rarely detected by the indirect in-process monitoring methods such as acoustic emission, cutting torque and motor current, was developed. Two HMI (Human Machine Interface) programs to embed the developed vision system into a Siemens open architecture controller, 840D, were developed. They are placed in sub-windows of the main window of the 840D and can be activated or deactivated either by a softkey on the operating panel or the M code in the NC part program. In the event that any type of tool breakage is detected, the HMI program issues a command for an automatic tool change or sends an alarm signal to the NC kernel. An evaluation test in a high-speed tapping machine showed that the developed vision system was successful in detecting breakages of small-diameter taps up to M1.     

Synthesis and properties of chitosan‐modified poly(acrylic acid)

Potassium persulfate (K₂S₂O₈) was used to initiate the polymerization of acrylic acid (AA) monomer in a chitosan (CS) solution. Both a poly(acrylic acid) (PAA) homopolymer and a CS‐co‐PAA copolymer were produced. When the amount of AA was increased from 5 to 40 g with 5 g of CS, the total monomer conversion was found to increase from 89 to 98% after 2 h of reaction at 70°C. In addition, the percentage of reacted AA monomer being converted to the CS‐co‐PAA copolymer (copolymerization efficiency) and the weight composition of the PAA portion in the copolymer (copolymer composition) both increased with the amount of AA added. The structures and properties of the synthesized CS‐modified PAA polymers were studied. In Fourier transform infrared spectra, the formation of a polyelectrolyte complex between CS chains and PAA chains could be observed. From the thermograms obtained via differential scanning calorimetry, we found that the presence of rigid CS chains increased the glass‐transition temperature of PAA. Thermogravimetric analysis revealed three stages of degradation of the synthesized CS‐modified PAA polymers. The swelling ratio of the CS‐modified PAA polymers depended on the pH value and had a maximum value in a buffer solution at pH 7. This was due to the changes in the morphological structure with the pH value. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

SPI discriminators among four psychological health-sickness levels.

Formed criterion groups representing 4 psychological health-sickness levels for each sex from among 87 hospitalized psychiatric patients and 145 normal adults on the basis of clinical judgments, and for normals, on the basis of an MMPI severity of pathology index. Magnitudes of mean scores for 14 scales of the Spiegel Personality Inventory were in rank order of pathology level for males and females. Univariate and multivariate methods were used to select 10 of the most promising scales: deviant response, deterioration feeling, self-dissatisfaction, intrusive thought, alienation, dread, future planlessness, olfactory minimizing, auditory minimizing, and tactual minimizing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geometric Programming: A Technical State-of-the-Art Survey

This paper presents a detailed survey of the latest techniques for solving large geometric programs. Geometric programming is a very powerful method for solving a large class of nonlinear programming problems, but it has been severely restricted in practice due to the inability to handle even moderate sized problems; that is, those possessing more than a few degrees of difficulty. During the past two years, a number of significant break-throughs have taken place in regard to handling both large problems and the general signomial, or signed programs. Several new algorithms, some untested in practice, are presented and discussed in this paper.     

Monolithic voltage regulators

Voltage regulation has been a specialty of semiconductors since the introduction of the Zener diode well over a decade ago. Now, there is a new dimension to the field?the monolithic voltage regulator. Available in a number of configurations that have specific advantages ranging over a variety of applications, this new component not only is giving its discrete counterpart a run for the money, but is showing a potential that easily surpasses even the most optimistic of earlier predictions.     

Hyperabrupt epitaxial tuning diodes

Theory, fabrication and testing of voltage-variable, tuning diode structures was performed yielding close comparisons of this theory with experiment. Six distinct diode voltage-capacitance characteristics of the form C = KV^?m were fabricated using precise and accurate computer control of the epitaxial layer structure.