Design of a Fracture Detection System based on Deep Program in a Convolutional Neural Network

This paper presents an efficient method for finding fractures in bones. For this purpose, the pre-processing set includes increasing the quality of images, removing additional objects, removing noise and rotating images. The input images then enter the machine learning phase to detect the final fracture. At this stage, a Convolutional Neural Networks is created by Genetic Programming (GP). In this way, learning models are implemented in the form of GP programs. And evolve during the evolution of this program. Then finally the best program for classifying incoming images is selected. The data set in this work is divided into training and test friends who have nothing in common. The ratio of training data to test is equal to 80 to 20. Finally, experimental results show good results for the proposed method for bone fractures.

Microstructure Analysis and Fatigue Behavior of Laser Beam Welding 2060-T8/2099-T83 Aluminum–Lithium Alloys

In this paper, the microstructure analysis and performance research of dual laser beam welded 2060-T8/2099-T83 aluminum–lithium alloys were carried out. First, the macroscopic morphology and microstructure characteristics of T-joint aluminum–lithium alloys under different welding conditions were observed. Then the effect of welding parameters and pore defects on tensile and fatigue properties of the weld were carried out and the experimental results were analyzed. It was found that the weld heat input has a significant influence on the penetration of the welded aluminum–lithium alloys joint. When the laser power is too high, the weld will absorb more laser energy and the increase in the evaporation of magnesium will further increase the weld penetration. When the penetration depth increases, the transverse tensile strength tends to decrease. There is no obvious rule for the effect of pore defects on the tensile strength of the weld. At the same time, the heat input of the weld is inversely proportional to the porosity. When the weld heat input increases from 19.41 to 23.33 kJ/m, the porosity decreases from 5.35% to 2.08%. During the fatigue test, it was confirmed that the existence of pore defects would reduce the fatigue life of the weld. In addition, from the analysis of the fatigue fracture morphology it can be found that when the porosity is low, the weld toe is the main source of fatigue cracks. The crack propagation zone shows a typical beach pattern and the final fracture of the base metal presents the characteristics of a brittle fracture. While, when the porosity is high, the crack source is mainly located at the pore defects. T-joint fractures from the inside of the weld and the fracture in the final fracture zone have obvious pore defects and dimples.

Influence of process temperature on fatigue crack growth rate of copper in equal channel angular pressing

The mechanical properties including Vickers hardness, tensile properties and fatigue crack growth rate and also, the microstructure of pure copper severely deformed by the ECAP in different temperatures, were studied in the present work. The equal channel angular pressing (ECAP) is a process applied to make fine grains microstructure. On the other hand, high temperature provides an opportunity for recrystallization of materials and reduces required force for ECAP at the same time. In this paper we have tried to find optimized temperature to perform ECAP effectively and reduce required force. The results indicated that the grains size can reduce from 18.2 to 2.7 µm by ECAP process. This study shows that because of the recrystallization phenomenon and reducing the effect of stress concentration and increasing the number of grain boundaries, the fatigue crack growth rate can decrease significantly. Also, it was found that the major improvement in tensile properties in all the temperature conditions and due to the applied simple shear to the copper, all the ECAPed specimens have demonstrated an enhanced hardness and resistance to fatigue crack growth. Although, these improvements decrease when the temperature increases. Finally, the SEM images of the fatigue fraction sections revealed three areas including, crack initiation, stable crack growth, and final fracture zone. It seems that the final fracture appeared to be a ductile fracture in the ECAP copper sample.

Geoecological aspects of the underground erosion development in loessial massifs of Uzbekistan

The problem of the development of the underground erosion is considered ion the article. The most brightly the underground erosion is shown in the massifs of the loessial breeds, which are widely developed in Uzbekistan. This phenomenon of consequences of the underground erosion development is described in science as the term “loessial pseudo-karst”. The loessial pseudo-karst have received the greatest spread and development in places of an active technogenesis since the second half of the XX century. Besides the territories connected with civil, industrial and hydrotechnical engineering the loessial pseudo-karst develops actively in the connection with active irrigation of the massifs formed with the loessial breeds. In case of not dosed water supply for the irrigation of agricultural grounds and the subsequent uncivilized dumping of surplus of water there is an extremely fast development of a loessial pseudo-karst (a day and even several hours). The negative consequences of the development of the underground erosion in loessial massifs lead to the violation of fragile balance of the natural and technical geosystems (NTG) and their conclusion from the condition of metastable balance. When forming pseudo-karst sinkholes near settlements, their unreasoned elimination by filling happens generally at the expense of solid and liquid household waste that considerably accelerates process of destruction of the massif, due to the impact on the loessial breeds of aggressive infiltrate. In case of active development of the underground erosion there is a final fracture of the loessial massif and formation of so-called pseudo-karst “bedlend”, that is sites where any economic activity is impossible. There are considerable economic, ecological and quite often social damages. It is easier to prevent a loessial pseudo-karst, than to fight against after its development has begun. The lack of due consideration to this promptly developing process annually causes the necessity of recultivation of the soil massifs broken by an underground erosion (pseudo-karst) or to the conclusion from the crop rotation of the most valuable irrigation lands in arid areas. The qualitative recommendations about the prevention of the development of a loessial pseudo-karst and minimization of damage are made.

Investigation of fractures mechanisms of railway axles

The paper gives a systematic overview of literature sources who consider impacts critical damage of mechanical, corrosive and thermal nature which may occur on railway axles during operation and which may be the causes of their fracture. The results of the research of the mechanisms that cause cracks, crack propagation and final fracture of the railway vehicle axle, such as material fatigue and the appearance of localized notches caused by paint (coating) separation, damage from ballast impact and pitting corrosion are presented. The influence of high temperatures and overheating on the axles was analyzed and an excerpt from the research published in one research report was given. Some significant suggestions for optimizing the design of the axles are highlighted which would take into account the analysis of time-varying axle stresses, stress spectrum in operation, axle tolerance to damage and the existence of residual surface stresses. The reliefs of the fracture surfaces of the axle after the railway incidents and the derailment of the rail vehicle from the rails are presented and explained.

CAPTURING OF UNEVEN DEFORMATIONS OF LIGHTENED 3D PRINTED PARTS

This paper deals with the problematics of tensile testing of maraging steel lightweight cylindrical samples with internal structures, intended for automotive application. The samples were made with DMLS technology and tensile tested under the static strain rate of 0.002 s-1. During the loading, uneven deformations and multiple necking occurred on the samples. The mentioned effect significantly affects the state of stress and deformation at the final fracture zone, as well as the total deformation into the fracture, which means that it actually distorts the standard tensile test record. Therefore, a methodology for capturing the deformation response using the ARAMIS optical system was proposed. The methodology is presented and verified by a set of experiments for BCC internal structure.

Effect of Impact Load on Concrete Containing Recycled Tire Rubber Aggregate with and without Fire Exposure

Over one billion tires are disposed into the environment each year and this has become a major environmental issue in the globe. Recycling of these waste tire rubbers in concrete has gained attention from researchers all around the world. In this study, the impact resistance of rubberized concrete exposed to fire is investigated experimentally in the laboratory. For that purpose, sixty specimens were made with five different mixes replacing their sand content partially with different percentages of tire rubber by weight ratios of 0% control, 6%, 12%, 18% and 24%. The water/cement ratio was kept constant at 0.393 in all the mixes. In each mix, fifteen concrete specimens with the size of (150 x 150 x 73) mm were prepared to expose to fire. Every three specimens were gradually exposed to fire for four various durations of (0, 15, 30, and 45) minutes. Each specimen was then tested in a drop-weight impact machine by dropping 2240-gr and 4500-gr hammers from heights of 280 mm and 450 mm. The average impact energy of three identical specimens required for the occurrence of the final fracture was calculated. The investigational results are compared with results of control samples. It is found that the impact energy considerably increased with an increase of the rubber replacement. It is, also, noted that any increase in the burning period of specimens results in a reduction of the impact energy and more early crushing of the rubberized concrete.

Fenomena Patah Lelah Batang Torak Mesin Kendaraan Niaga

Batang torak (connecting rod) mesin kendaraan niaga mengalami patah di daerahconnecting rod shank, pada saat kendaraan tersebut sedang berjalan.Untuk mengetahui penyebab terjadinya kerusakan tersebut, maka perlu dilakukan pemeriksaan dan pengujian di laboratorium terhadap patahan batang torak tersebut, meliputi : pemeriksaan fraktografi, pemeriksaan metalografi, pengujian kekerasan, analisa komposisi kimia dan pemeriksaan dengan SEM. Dari hasil pemeriksaan dan pengujian diketahui bahwa patahnya connecting rod shankdisebabkan karena mengalami patah lelah (fatigue fracture). Bila dilihat dari luasan area lelah (fatigue area) yang lebih besar dibandingkan dengan sisa patahannya (final fracture), maka dapat diketahui bahwa connecting rod shanktelah mengalami patah lelah akibat beban unidirectional bending, dengan tegangan nominal yang rendah (low nominal stress) tanpa adanya konsentrasi tegangan (no stress concentration). Struktur mikro connecting rod shank adalah ferrite dan pearlite, Dari hasil pemeriksaan komposisi kimia dan pengujian kekerasan menunjukkan jenis materia daril connecting rod shank sesuai dengan spesifikasi yang digunakan, yaitu JIS G 4051 Grade S 20 C.Kata kunci : Batang torak, Patah lelah, Beban tekuk searah, Tegangan nominal rendah, Tanpa konsentrasi teganganAbstractThe connecting rod engine of commercial vehicle was suffering damage on the coneecting rod shank area, while its running. To determine the cause of the damage, it is necessary to do inspection and test on the connecting rod fracture in the laboratory, includes: fractography examination, metallography examination, hardness testing, chemical composition analysis and SEM examination. From the results of inspection and testing are known that the fracture of connecting rod shank caused by fatigue fracture. By observing that extent of fatigue area is larger than the final fracture, shows that the connecting rod shank has suffered unidirectional bending fatigue due to load, with nominal low stress and no stress concentration. Connecting rod shank microstructure is ferrite and pearlite, From the results of the chemical composition and hardness testing indicates the type of connecting rod shank material is in accordance with the specification, JIS G 4051 Grade S 20 C.Keywords : Connecting rod, Fatigue fracture, Unidirectional bending, Low nominal stress, No stress concentration