Impact Fracture Behavior of Ceramics and PE-Fiber-Reinforced Mortars

2011 ◽  
Vol 484 ◽  
pp. 75-81
Author(s):  
Yasuhiro Tanabe ◽  
Masayoshi Yamada ◽  
Akihiro Sasoh ◽  
Minoru Kunieda ◽  
Kiyoto Sekine ◽  
...  

Ceramics will be used for power generating systems in the next generation. When they are used in this system, damage due to foreign object is inevitable. However, few systematic and comprehensive investigations have been reported on this subject. Various ceramics including fiber-reinforced mortars were investigated to understand their behavior when impacted by a spherical projectile. The volume of the cone cracks was large in ceramics which underwent transgranular fracture, while it was small in which underwent an intergranular one. Even though the energy consuming ability by the formation of surfaces was low up to 3.5% of the kinetic energy of a projectile, this ability increased with the ratio of the intergranular fracture to the transgranular one. Boron carbide showed a lower pressure as compared to the other ceramics. Fiber reinforcing increased the ballistic limits, but no clear advantage was suggested when absorbing the kinetic energy of a projectile far over its limits.

2011 ◽  
Vol 488-489 ◽  
pp. 214-217
Author(s):  
Masakazu Terai ◽  
Koichi Minami

Fiber reinforced concrete is superior to plain concrete in toughness, which is the energy absorption at fracture. This study is intended to use fibers extracted from bamboo for tensile reinforcement of concrete. Some experiments were carried out to explore the possibility of bamboo fiber reinforced concrete. As a result, the compressive strength of concrete with 1-2% bamboo fiber is little different from the case without reinforcement. On the other, the splitting tensile and the flexural strength significantly increased with an increased volume fraction of fibers. The strength of bamboo fiber reinforced concrete increased with increasing fiber content as a result of fiber bridging.


Author(s):  
A. D. Kozlov ◽  
Yu. P. Potekhina

Although joints with synovial cavities and articular surfaces are very variable, they all have one common peculiarity. In most cases, one of the articular surfaces is concave, whereas the other one is convex. During the formation of a joint, the epiphysis, which has less kinetic energy during the movements in the joint, forms a convex surface, whereas large kinetic energy forms the epiphysis with a concave surface. Basing on this concept, the analysis of the structure of the joints, allows to determine forces involved into their formation, and to identify the general patterns of the formation of the skeleton.


2020 ◽  
Vol 240 ◽  
pp. 117681
Author(s):  
Mehran Aziminezhad ◽  
Sahand Mardi ◽  
Pouria Hajikarimi ◽  
Fereidoon Moghadas Nejad ◽  
Amir H. Gandomi

Author(s):  
Arputham Arul Jeya Kumar ◽  
Muniyandi Prakash ◽  
Abburi Lakshmankumar ◽  
Kesuboyina Haswanth

In this work, the wear loss of basalt fiber reinforced polypropylene/polylactic acid polymer composite was analyzed using pin-on-disc under dry sliding conditions. The polypropylene, polylactic acid, and basalt fiber (chopped fiber) are melted and mixed homogeneously using a twin-screw extruder, which is followed by an injection molding technique for specimen preparation. The specimens are named as PPB1 (polypropylene, 50%; polylactic acid, 35%; basalt fiber, 15%), PPB2 (polypropylene, 55%; polylactic acid, 30%; basalt fiber, 15%), and PPB3 (polypropylene, 60%; polylactic acid, 25%; basalt fiber, 15%) based on their weight fraction. The wear rate and coefficient of friction are measured for each sample subjected to three different loads and sliding velocities. It is observed from the wear mapping that the wear loss of sample PPB3 is relatively less when compared with the other samples. The scanning electron microscope images of the worn-out region of the sample reveal the fracture and dislocation of fibers in the matrix. The sample PPB3 shows low wear loss. It is due to the better cohesion between the fiber and the matrixes when compared with the other samples.


This study of the thallium fluoride spectrum was undertaken as part of a detailed investigation into the molecular spectra of the series of heavy diatomic fluorides HgF, TlF, PbF and BiF. Whereas the spectra of PbF (Rochester 1936) and BiF (Howell 1936), of which analyses have already been published, contain no very unusual features the TlF spectrum is particularly rich in them, so that it has seemed desirable to extend the original investigation in order to include the other halides of thallium. The absorption spectrum of the fluoride has already been examined by Boizova and Butkow (1936), their findings being summarized below: 1— A continuum at 2200 A appears when the absorption tube is at a temperature of 155° C. Its long-wave edge moves towards the red with increase of temperature, being at 2700 for the unsaturated vapour and at 3400 for the saturated vapour when the temperature is 280° C. They attributed this continuum to the dissociation of Tl 2 F 2 . Tl 2 F 2 → 2TlF + kinetic energy.


2006 ◽  
Vol 326-328 ◽  
pp. 1435-1438 ◽  
Author(s):  
Abdul A. Yumaryanto ◽  
Jae Bum An ◽  
Li Li Xin

In this paper we present the design and prototype of a six-legged walking robot which uses Lightweight Piezoceramic Composite curved Actuator (LIPCA) as its actuator. LIPCA consists of multiple layers of glass/epoxy and carbon/epoxy that encapsulate a unimorph piezoelectric ceramic actuator. It uses lightweight fiber-reinforced plastic layers, and it is a lighter structure and generates a higher force and a larger displacement than other conventional piezo-composite type actuators. Like most six-legged walking insects including cockroaches, our robot uses the alternating tripod gait where the front and rear legs on the same side move together with the middle leg on the other side for its locomotion. Two LIPCA strips in different phases are used for actuating each tripod so that only one tripod may touch the ground ensuring static stability while walking. All the experiments with the prototype show that LIPCA can be used as an alternative actuator for small and light mobile robots.


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