1.

Record Nr.

UNINA9910710520003321

Autore

Duewer David L

Titolo

NIST micronutrients measurement quality assurance program summer 2002 comparability studies : results for round robin LII fat-soluble vitamins and carotenoids in human serum and round robin 17 ascorbic acid in human serum / / David L. Duewer; Margaret C. Kline; Sam A. Margolis; Katherine E. Sharpless; Jeanice B. Thomas

Pubbl/distr/stampa

Gaithersburg, MD : , : U.S. Dept. of Commerce, National Institute of Standards and Technology, , 2013

Descrizione fisica

1 online resource (55 pages) : illustrations (some color)

Collana

NISTIR ; ; 7880-20

Altri autori (Persone)

DuewerDavid L

KlineMargaret C

MargolisSam A

SharplessKatherine E

ThomasJeanice B

Soggetti

Quality assurance

Trace elements in nutrition

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Note generali

"June 2013."

Contributed record: Metadata reviewed, not verified. Some fields updated by batch processes.

Title from PDF title page (viewed July 1, 2013).

Nota di bibliografia

Includes bibliographical references.



2.

Record Nr.

UNINA9910827619803321

Autore

Block Tim Berend

Titolo

Analysis of the mechanical response of impact loaded composite sandwich structures with focus foam core shear failure / / Tim Berend Block

Pubbl/distr/stampa

Berlin : , : Logos Verlag Berlin, , [2014]

©2014

ISBN

3-8325-9534-1

Descrizione fisica

1 online resource (238 pages)

Collana

Science-Report aus dem Faserinstitut Bremen

Disciplina

620.110287

Soggetti

Materials - Testing

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Note generali

PublicationDate: 20141220

Sommario/riassunto

Long description: Sandwich structures are an economically and structurally efficient way of designing large integral composite parts. In the aerospace industry pre-impregnated face sheets and honeycomb core structures can be considered as industry standard while e.g. naval structures and wind turbine blades typically use vacuum infusion technology with polymer foam cores. Application of the less costly infusion technology in the aeronautical industry requires a thorough understanding of the damage tolerance including low velocity impact as a frequent source of damaging events.  At low impact energies damage in composite foam core sandwich structures is limited to core crushing and local face sheet delaminations. Higher impact energies may initiate the competing failure modes face sheet rupture and core shear failure depending on impact, geometric and material parameters. Face sheet rupture leads to severe local damage with typically good visibility, while core shear failure leads to cracks and rear face sheet debonding of the foam core with less visibility.  This work investigates the low velocity impact response of sandwich structures with carbon fiber reinforced plastic (CFRP) face sheets and a polymeric foam core using experiments at room temperature and at -55 Grad Celsius. An analytically derived failure mode map is presented as a simple tool for design guidelines



while the explicit finite element method is applied for a more detailed description of the sandwich impact process. Both models are used to analyze the impact response and describe relevant sensitivity parameters of sandwich structures.