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Specific Strength (specific + strength)

Distribution by Scientific Domains

Polymers and Materials Science	85%

Selected Abstracts

Improvement in the Specific Strength by Arranging Closed Pores in Fully Densified Zirconia Ceramics,

ADVANCED ENGINEERING MATERIALS, Issue 1-2 2009
Akira Kishimoto
Superplastic-foamed porous ceramics containing numerous closed pores were fabricated. The bending strength of the fabricated ceramics with the smallest pores was close to half that of fully dense ones, even with a porosity of 27%. The smaller pores were introduced selectively between top and bottom surfaces. The resultant dense/porous/dense layered ceramics had a specific mechanical strength greater than that of monolithic dense ceramics. [source]

In Situ Damage Detection With Acoustic Emission Analysis During Cyclic Loading of Wire Reinforced EN AW-6082,

ADVANCED ENGINEERING MATERIALS, Issue 7 2010
Kay André Weidenmann
In the field of lightweight construction, hybrid structures such as reinforced metal matrix composites are highly qualified materials. The direct composite extrusion process allows for continuous manufacturing of wire reinforced aluminum matrix profiles. The aim is to increase the stiffness and specific strength in a way that the composite material shows better mechanical properties than the single matrix material. To determine and locate damage evolution during cyclic loading of spring steel reinforced EN AW-6082 matrix the acoustic emission analysis is used. Furthermore it allows for getting more information about the damage mechanisms during fatigue of the matrix and the final failure of the reinforcing element. The current work also includes the determination of damage evolution using strain measuring methods. [source]

Investigation of Mechanical and Microstructural Characteristics of Al,Mg Compounds,

ADVANCED ENGINEERING MATERIALS, Issue 7 2009
Reimund Neugebauer
The presented approach of generating composites offers new possibilities for the combination of two light metal alloys into one semifinished product of high specific strength and corrosion resistance. A test device based on the forming method of lateral extrusion was designed to manufacture metallic compounds. The created interface layer is characterized by the formation of new phases and affects the mechanical properties of the whole compound. [source]

Mechanical Properties and Environmental Behavior of a Magnesium Alloy with a Nano-/Sub-Micron Structure

ADVANCED ENGINEERING MATERIALS, Issue 9 2007
E. Aghion
Abstract Newly developed magnesium alloys with a consolidated nano/sub-micron structure and substantially higher specific strength may be considered as an interesting candidate for super-light high-strength applications. Consolidated nano/sub-micron structure applies to alloys with a combined microstructure of nano-crystalline and sub-micron grains. The aim of the present study was to explore the mechanical and environmental behavior of a consolidated nano/sub-micron magnesium alloy with the composition of AZ31. This was required in order to evaluate the applicability of this new structured alloy for practical applications. Although the nano/sub-micron structured alloy has more than twice the hardness and strength of the conventional alloy, its ductility and corrosion resistance were significantly lower. In addition, its stress corrosion characteristics were inferior. The significant limitation of the nano-structured alloy, in terms of ductility and corrosion performance, restricts its potential use as a structural material for practical applications. [source]

Ceramic Matrix Composites: A Challenge in Space-Propulsion Technology Applications

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2005
Stephan Schmidt
Various technology programs in Europe are concerned, besides developing reliable and rugged, low-cost, throwaway equipment, with preparing for future reusable propulsion technologies. One of the key roles for realizing reusable engine components is the use of modern and innovative materials. One of the key technologies that concerns various engine manufacturers worldwide is the development of fiber-reinforced ceramics,CMCs (ceramic matrix composites). The advantages for the developers are obvious,the low specific weight, the high specific strength over a large temperature range, and their great damage tolerance compared with monolithic ceramics make this material class extremely interesting as a construction material. Over the past few years, the EADS-ST Company (formerly DASA) has, together with various partners, worked intensively on developing components for hypersonic engines and liquid rocket propulsion systems. In the year 2000, various hot-firing tests with subscale (scale 1:5) and full-scale nozzle extensions were conducted. In this year, a further decisive milestone was achieved in the sector of small thrusters, and long-term tests served to demonstrate the extraordinary stability of the C/SiC material. Besides developing and testing radiation-cooled nozzle components and small-thruster combustion chambers, EADS-ST worked on the preliminary development of actively cooled structures for future reusable propulsion systems. In order to get one step nearer to this objective, the development of a new fiber composite was commenced within the framework of a regionally sponsored program. The objective here is to create multidirectional (3D) textile structures combined with a cost-effective infiltration process. Besides material and process development, the project also encompasses the development of special metal/ceramic and ceramic/ceramic joining techniques as well as studying and verifying nondestructive investigation processes for the purpose of testing components. [source]

Sandwich structures with composite inserts: Experimental studies

POLYMER COMPOSITES, Issue 5 2009
N.K. Naik
Experimental studies are presented on the performance of insert assemblies of the sandwich structures under localized through-the-thickness compressive loading. Through-the-thickness and partially inserted fully potted inserts are studied. Insert materials considered are: aluminum and 3D woven composite. Experimental results are compared with the analytical predictions. It is observed that the specific strength of 3D woven composite inserts is more than that of aluminum inserts. Further, it is observed that the specific strength of through-the-thickness inserts is more than that of partially inserted fully potted inserts. Delamination between upper face plate and core material and sliding of attachment/insert within the core are the main modes of failure initiation. Quantitative results are presented for typical cases. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source]

Comparison of triple quadrupole, hybrid linear ion trap triple quadrupole, time-of-flight and LTQ-Orbitrap mass spectrometers in drug discovery phase metabolite screening and identification in vitro , amitriptyline and verapamil as model compounds

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2010
Timo Rousu
Liquid chromatography in combination with mass spectrometry (LC/MS) is a superior analytical technique for metabolite profiling and identification studies performed in drug discovery and development laboratories. In the early phase of drug discovery the analytical approach should be both time- and cost-effective, thus providing as much data as possible with only one visit to the laboratory, without the need for further experiments. Recent developments in mass spectrometers have created a situation where many different mass spectrometers are available for the task, each with their specific strengths and drawbacks. We compared the metabolite screening properties of four main types of mass spectrometers used in analytical laboratories, considering both the ability to detect the metabolites and provide structural information, as well as the issues related to time consumption in laboratory and thereafter in data processing. Human liver microsomal incubations with amitriptyline and verapamil were used as test samples, and early-phase ,one lab visit only' approaches were used with all instruments. In total, 28 amitriptyline and 69 verapamil metabolites were found and tentatively identified. Time-of-flight mass spectrometry (TOFMS) was the only approach detecting all of them, shown to be the most suitable instrument for elucidating as comprehensive metabolite profile as possible leading also to lowest overall time consumption together with the LTQ-Orbitrap approach. The latter however suffered from lower detection sensitivity and false negatives, and due to slow data acquisition rate required slower chromatography. Approaches with triple quadrupole mass spectrometry (QqQ) and hybrid linear ion trap triple quadrupole mass spectrometry (Q-Trap) provided the highest amount of fragment ion data for structural elucidation, but, in addition to being unable to produce very high-important accurate mass data, they suffered from many false negatives, and especially with the QqQ, from very high overall time consumption. Copyright © 2010 John Wiley & Sons, Ltd. [source]