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Two manufactured metal building warehouses loaded with agricultural products failed in service. Inspection revealed considerable damage to the structure and the foundation. The building owner filed suit against the building supplier, the building erector, and the soils testing laboratory whose engineer had designed the foundation. The agricultural product imposed substantial outward lateral pressures on the walls of the structures. Review of the available design documents indicated that these loads had not been accounted for in design. A structural analysis revealed that elements of the structure were underdesigned for the agricultural product loads. In addition, the foundation did not have any slab reinforcement to resist the loads. To prevent similar failures, these loads must be accounted for in design. The steel structure design and foundation design were both deficient. A contributing factor was the lack of communication between the designer of the structure and the designer of the foundation, due to the lack of a single engineer of record to take responsibility for the buildings. CE Database keywords: Structural failure; Litigation; Loads; Building design.

Byline: Chris L. Pettit Widespread interest in uncertainty quantification methods for airframe design and certification is driven by the desire to realise acquisition and operational cost savings through increased reliance on analysis; the goal being to design and produce more robust airframes. General sources of uncertainty are described, that complicate airframe design and testing, thereby contributing to the high cost of airframes. Recent applications of uncertainty quantification are reviewed with the objective of highlighting promising research and transition applications. Finally, several challenges and needs are explored to suggest future steps that must be completed to enable practical application of uncertainty quantification in airframe design and certification.

Byline: Richard F. Banglmaier, Lan Wang, Priya Prasad Injury risk research has compared parametric and non-parametric methods of developing risk curves to express bio-mechanical data, accounting for injury mechanism complexity and censorship assumptions. However, risk curves may over-predict the injury risk under these assumptions. This may occur because inherent biases in bio-mechanical data may influence the risk curve. Interval censoring can be applied when an interval is known within a normally doubly censored data set. Parametric and non-parametric models were applied to several data sets, evaluating their response to bias and interval censorship. Accounting for biases may or may not improve the fit to the data set depending on the risk curve. Interval censoring caused a decrease in the goodness of fit to the experimental data. While not normally a desired outcome, interval-censoring may actually produce risk curves that better predict the injury risk of the population of interest instead of the experimental data.

Byline: N.I. Kobasko The phenomenon of superstrengthening of metals was for the first time discovered in Kobasko (1967) and discussed many times in scientific literature (Kobasko, 1992, 1979, 1980; Ganiev et al., 1980). It lies in the following: very intensive cooling within the martensite range results in additional strengthening (superstrengthening) of material with simultaneous improvement of its plastic properties. There is also a different point of view (Gul et al., 1989; Sverdlin et al., 2003), according to which very intensive cooling within the range higher the martensite start temperature Ms results in additional strengthening of metals due to 'freezing of vacancies', formed during heating. The author has shown that intensive cooling higher Ms does not result in superstrengthening of material and only very intensive cooling within the range of Ms/Mf yields positive results. It is of great practical and scientific interest to discuss this information widely and apply it in production.

Byline: L.C. Casteletti, P.E.B. Kinap, P.A.P. Nascente The purpose of the present work consists in obtaining ductile cast iron that will be used in the shaft production, with the following mechanical characteristics: minimum tensile strength of 700 N/mmO, minimum yield strength of 450 N/mmO, minimum elongation of 5%, and hardness in the range of 235 HB to 285 HB. The most adequate microstructure for obtaining these desired mechanical characteristics consists of spheroidal cementite dispersed in a ferritic matrix, and this microstructure can be obtained by annealing a pearlitic microstructure or tempering a martensitic microstructure. All types of heat treatments used in this work, depending on the treatment time, led to the formation of spheroidal cementite. The material, normalised and annealed for two hours at 700uC, yielded the desired mechanical characteristics: ultimate tensile strength and yield strength values of 827 N/N/mmO and 547 N/N/mmO, respectively, elongation of 7% and hardness value of 277 HB.

Byline: Xianwu Ling, Harish P. Cherukuri, R.E. Smelser, Paul T. Wang A single-internal variable constitutive model is used to predict the micro-hardness for a commercial purity aluminium alloy subjected to various quenching histories. The delayed quenching, higher nucleate boiling amplitude, and wider nucleate boiling range increase the micro-hardness. A limited study of the effect of cylinder size does not yield significant changes in the microhardness. The modelling methodology developed here can be used in modelling commercial quenching processes.

Byline: Ridha Hambli In this paper, the results obtained by 3-D shell elements numerical simulation of superplastic sheet forming is compared with the experimental ones to verify the validity of the finite element model developed to predict the optimum pressure cycle, the deformed shapes, the distributions of the strain rate and the evolution of the thickness during the forming process. The finite element shell material model proposed here, includes membrane, bending and out-of-plane shear effects leading to a better characterisation of the material behaviour under forming conditions. Final results of the FEM modelling agree with the experimental ones.

Thermodynamic and kinetic properties of group III metal nitrides Me(Al,Ga,In)N-Me(l)-N2 systems are strongly influenced by the high binding energy of molecular nitrogen which favours the decomposition of these compounds into the constituents, severely limiting the growth possibilities of these crystals. From all three nitrides, the AlN sizeable crystals have been grown from the vapour only. In contrast, the best GaN and InN crystals were grown from solution using different nitrogen sources: ammonia (NH3), plasma-activated nitrogen, or molecular nitrogen (N2) under high pressure. AlN crystals grown from solution have low crystallographic quality and needle-like unstable morphology. They are electrical insulators. GaN hexagonal plate-like crystals, grown under high nitrogen pressure, have high crystallographic quality, sufficient for epitaxy. GaN undoped crystals, are heavily n-type whereas those doped by Mg or Be are usually semi-insulating. InN crystals, obtained by the plasma method, are similar to undoped GaN crystals - they possess high concentration of free electrons.

Byline: M. Nogami, T. Hayakawa The sol-gel method was applied to the preparation of glasses doped with nano-sized CdS and SnO2 particles of 510nm in diameter. Band gap energies of the nano-sized particles exhibited large blue shift compared with those of bulk crystals and the energy shift was reciprocally proportional to the square of the particle size. The third order nonlinearity of the nano-sized CdS particles showed the maximum value of 1.5610-10 esu at the optical absorption edge position. The Eu+ ions were doped in the nano-sized CdS and SnO2 particles-precipitated glasses, of which the fluorescence intensities were enhanced by the existence of the nano-sized particles. The energy absorbed by the quantum-dot effect in the nano-sized particles is efficiently transferred into the Eu+ ions to cause the high emission. Particularly, the Eu+ ions doped in nano-sized SnO2-containing glasses exhibited the enhanced fluorescence of the 5D0→7Fj transitions. When excited at the energy corresponding to the absorption edge of the SnO2 nanocrystals, the fluorescence intensities of the Eu+ ions were enhanced up to 150 times higher than the glass without nanocrystals.

Byline: M. Britchi, M. Olteanu, G. Jitianu, M. Branzei, D. Gheorghe, P. Nita Vitroceramic coatings from the oxidic system SiO2-CaO-B2O3-TiO2-R2O (R = Na and K) were applied on metallic supports (titanium and austenitic steels with high Cr and Ni contents). The coating procedure was classical enamelling. The metals were coated by either immersion or by painting over a thin layer from a mixture of frit (having the best composition for each metallic support) with a liquid mixture (triethanol amine ethyl : alcohol = 1 : 10), which was subsequently fired at the enamelling temperature. A good adherence between the two different materials has been thus achieved. Vitroceramic coating - metallic support couples were then characterized by optical microscopy (OM), electronic microscopy (EDS and WDS), and X-ray diffraction (XRD). The adherence of the vitroceramic layers onto metallic supports was tested by microhardness trials at the interface. The processes at the interface, i.e. gas bubble evolution, micropore formation, chemical bonding and diffusion, were evidenced. These coating layers can be employed as both bioactive and biocompatible materials.

Byline: Su-Hai Hsiang, Sheng-Li Lin In the simulation of bulging in shape rolling, for the purpose of CPU time saving, a complex method which combined the 3D-FEM with the slab method was developed in this paper. In this model, the deformation zone in the billet was divided into several proper slabs according to the shapes of boundary, and each slab was analysed by 3D-FEM. Then, the equilibrium of the longitudinal force and the condition of volume consistency were applied. Finally, the tendency of metal flow, roll pressure, stress and strain rate can be calculated. Compared with the traditional 3D-FEM, the results of this complex model were acceptable. This model had the merit of saving computation time and memory capacity, and it was also very suitable for performing in personal computers.

Byline: A. Molinari, G. Straffelini In order to increase the mechanical properties of the diffusion layer of the nitrided Fe-Ni-Cu-Mo-C sintered alloy, the nitriding temperature was varied over a wide range, and some experiments at a temperature higher than that of the eutectoid reaction in the Fe-C-N system were carried out. In order to control the diffusion depth and, in turn, the dimensional variations, different pre-treatments for the closure of the interconnected pores were investigated. The microhardness profiles of the diffusion layers obtained at different temperatures were compared and interpreted on the basis of the microstructural transformations occurring during nitrogen diffusion. The results show that high temperature nitriding can really improve the mechanical properties of the treated material.

Byline: M. Manuela Oliveira Research on PM high-speed steels and their composites started at INETI in 1984. The PM route adopted has been either vacuum or atmosphere sintering of water atomised powders compacted to shape. A wide range of equipment covers the several steps of this processing route water atomisation, compaction (uniaxial or isostatic), sintering, heat treatment and characterisation (microstructure and mechanical properties). This paper presents results obtained in the current research activity on these materials at INETI in the frame of European Community (EC) contracts and also in collaboration with some Portuguese industries (tool manufacturers).

Byline: L.P. Kashitsin, A.L. Khudoley The method was developed of centrifugal moulding in layers to obtain axially symmetric contours of the free surface of formed powder layers. The interval of speeds of all powder layer moulding were determined taking into account the slippage of powder mass concerning the matrix's internal surface. It was found that the maximum possible angular acceleration and matrix rotation velocity depend on the moulding speed time interval for given values of powder layer thickness. A system for choosing optimal parameters and for the regulation of the moulding process regimes is proposed. The method makes it possible to mould spherical powders of big, middle and small dispersivity and even less than 63 micrometres, as well as powder materials with incorrectly formed particles.

Byline: V.M.A. Leitao, M.H. Aliabadi In this paper, a boundary element method of simulating crack growth in the presence of residual stress fields is presented. The method presented is an elastoplastic fracture mechanics (EPFM) approach for crack growth simulation. A nonlinear J-integral is used in the fatigue life calculations. This is shown to agree well with experimental measurements of crack growth in prestressed open hole specimens. Results are also pre- sented for the case where the prestress is applied to specimens which have been precracked.

Designed for TIG welding operators who work long distances from the power source, Welding Nozzle International's TIG Torch Construction Bucket contains every tool and accessory field operators need. The 6.5-gallon [...]

Abresist Corp., Urbana, Ind., manufactures Vautid wear plates through a hardfacing process that produces high carbide content in the wear surface, a strong boundary layer, and little mixing of the […]

Gas-atomized powders are available from Hoganas North America Inc., Indianapolis, Ind., a subsidiary of Hoganas AB, Sweden. Materials available include nickel-base, cobalt-base, iron-base, and carbide grades. Applications include powder welding, […]

Low-modulus carbon-carbon composites have been fabricated into plates that conduct heat almost as well as aluminum at two-thirds the weight, reports BFGoodrich Supertemp, Calif. The work was supported by the […]

January 1925: The Pittsburgh Chapter [of A.S.S.T.] held its December meeting on the 2nd of the month in the Assembly Room of the Fort Pitt Hotel. Preceding the paper of […]

AAA Quench Oil provides rapid, uniform cooling for austenitized low and medium-alloy steels, explains Heatbath/Park Metallurgical, Springfield, Mass. The quenchant is used at 55 to 70°C (130 to 160°F) for […]

Thomas Steel Strip has long been a leader in the field of continuous steel strip plating. By managing every phase of production, TSS is able to strictly control quality throughout […]

Mechanical and physical properties of pure refractory metals Property Niobium Structure and atomic properties Atomic number 41 Atomic weight 92.9064 Density at 20°C 8.57 (0.310) (70°F), g/[cm.sup.3] (lb / [in.sup.3].) […]

Ultimate tensile strength at room temperature UTS, UTS, Material MPa ksi Boron fibers 3450 500 Aramid fibers 2750 400 Iridium wire, 2480 360 hot-worked (max) Rhodium 2069 300 Cobalt MP35N, […]

The nine service centers of Titanium Metals Corp., Denver, Cola., will stock zirconium mill products for the chemical processing industry and other non-nuclear applications. Timet will produce plate, sheet, bar, […]

Ametek Specialty Metal Products is now supplying plastics manufacturers with stainless steel powder additives for compounds used to protect chips, semiconductors, printed circuit boards and wire from electromagnetic interference and [...]

C.I. Hayes Inc. has concluded a recent reengineering of its entire product line and approach to the business of heat treating. For customers, the immediate benefit is a clearly focused […]

Tenaxol Inc. is a world leader in the development and application of polymer quenching fluids for the heat treatment of ferrous and nonferrous materials. The company was founded by R. […]