High-velocity Impact Fragmentation of Brittle, Granular Aluminum Spheres

Fragmentation processes in impact of spheres.

We study the brittle fragmentation of spheres by using a three-dimensional discrete element model. Large scale computer simulations are performed with a model that consists of agglomerates of many particles, interconnected by beam-truss elements. We focus on the detailed development of the fragmentation process and study several fragmentation mechanisms. The evolution of meridional cracks is st...

Fragmentation of ice by low velocity impact

Low velocity impact experiments (0.14 to l km/ s) carried out in polycrystalline water ice targets at 257 and 81 K resulted in interactions which can be assigned to four fragmentation classes, cratering, erosion, disruption, and total fragmentation. Specific kinetic energies for the transitions between these classes range from l x 105 to 7 x 105 ergs/g for 81 K ice and from 3 x 105 to 2 x 106 e...

the impact of computer-assisted language learning on achievement motivation of high school students

چکیده انگیزه دلیل اصلی رفتارهای ما است. به نظر می رسد انگیزه جزء جدایی ناپذیر فرایند یادگیری باشد. ارزش ذاتی موفقیت تمایل به پیشرفت را در یادگیرنده ایجاد میکند. به عبارت ساده این تمایل انگیزه پیشرفت نامیده میشود. انگیزه پیشرفت را میتوان در احساس یادگیرنده هنگام چالش با درس های مدرسه، لذت انجام فعالیت درسی، یا حس کشف پاسخ مشاهده کرد.حتی ممکن است انگیزه پیشرفت را در تلاش یادگیرنده برای جلب تایید...

Single and multiple fragmentation of brittle geomaterials

Compression and low-velocity impact behavior of aluminum syntactic foam

We report quasi-static compression and impact behavior of aluminum syntactic foams (ASF) produced by melt infiltration. Aluminum syntactic foams with relative density of 0.46 were produced using hollow alumina spheres (4.45 mm and 3.05 mm) randomly situated in a mold and two types of aluminum alloy (1100 and 6061). The impact behavior was investigated using an instrumented drop tower. We invest...