scholarly journals Study on synergistic system of energy-absorbing yielding anti-impact supporting structure and surrounding rock

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Yimin Song ◽  
He Ren ◽  
Hailiang Xu ◽  
Xu Guo ◽  
Zheng Chen ◽  
...  

AbstractThrough the improvement of supporting structure and the utilization of the interaction between surrounding rock and supporting structure, the synergistic system of energy-absorbing yielding anti-impact supporting structure and surrounding rock is established. The process of energy absorption device, energy-absorbing yielding anti-impact supporting structure and synergistic system under impact is simulated to analyze the properties of them. The following conclusions could be drawn. The deformation and yielding process under compression of energy absorption device is divided into five stages. Compared with the traditional supporting structure, the energy-absorbing yielding anti-impact supporting structure has the reaction force with lower value and smaller fluctuation range before the deformation of the energy absorption device reaches the third ascending section. The synergy between surrounding rock and supporting structure plays an important role in roadway support. Compared with the supporting structure without surrounding rock, the reaction force of the supporting structure in the synergistic system is lower, and a stationary stage is added in the early stage of the reaction force curve.

2013 ◽  
Vol 353-356 ◽  
pp. 252-257
Author(s):  
Ren Liang Shan ◽  
Xiang Song Kong ◽  
Ji Jun Zhou ◽  
Wen Feng Zhao ◽  
Yu Tao ◽  
...  

Scientific supporting design is of great significance to ensure coal roadway stability. The three-step supporting design method is put forward for coal roadway support: The first step is preliminary design, determine the range of each supporting parameter according to the theoretical calculation and supporting experiences; the second step is numerical simulation calculation, choose the reasonable one through the comparison of schemes; the third step is field monitoring, verify the scheme applicability. After applying the three-step supporting design method to study 3# coal seam roadway in Guandi mine, the optimal supporting scheme is obtained, and good results of underground roadway are achieved, which ensure the stability of roadway surrounding rock. Meanwhile, some rules are summarized which provide references for future roadway supporting design.


2012 ◽  
Vol 256-259 ◽  
pp. 1312-1315
Author(s):  
Hong Li Wang ◽  
Xian Tang Zhang ◽  
Wei Bao ◽  
Hu Xiu

Based on a large number of surrounding rock stability, it sums up the classification of surrounding rock, nature and failure mechanism in the underground engineering. This paper introduces a underground tunnel hanging assembly support, the supporting structure can effectively solve the problem of insufficient rigidity of the roadway support, and provide a supporting structure with a certain amount of shrinkage.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3613
Author(s):  
Baohui Yang ◽  
Yangjie Zuo ◽  
Zhengping Chang

Foams are widely used in protective applications requiring high energy absorption under impact, and evaluating impact properties of foams is vital. Therefore, a novel test method based on a shock tube was developed to investigate the impact properties of closed-cell polyethylene (PE) foams at strain rates over 6000 s−1, and the test theory is presented. Based on the test method, the failure progress and final failure modes of PE foams are discussed. Moreover, energy absorption capabilities of PE foams were assessed under both quasi-static and high strain rate loading conditions. The results showed that the foam exhibited a nonuniform deformation along the specimen length under high strain rates. The energy absorption rate of PE foam increased with the increasing of strain rates. The specimen energy absorption varied linearly in the early stage and then increased rapidly, corresponding to a uniform compression process. However, in the shock wave deformation process, the energy absorption capacity of the foam maintained a good stability and exhibited the best energy absorption state when the speed was higher than 26 m/s. This stable energy absorption state disappeared until the speed was lower than 1.3 m/s. The loading speed exhibited an obvious influence on energy density.


Author(s):  
Т.А. Богумил

В статье предлагается концепция жизни и творческого роста В.М. Шукшина сквозь призму тезаурусного и кластерного подходов. Объяснительными «персональными моделями» для интерпретации биографического текста писателя являются кластеры Мартина Идена, Гамлета и Степана Разина. Ранее биографы и литературоведы указывали на важность этих персон для Шукшина, но разрозненно. Впервые предпринята попытка свести указанные персональные модели воедино, в целостный сюжет становления писателя в пространстве культуры. На разных этапах эволюции автора доминирует одна из указанных моделей, последовательно сменяя друг друга, но не вытесняя, а «внахлест». Ранний этап творчества, ориентированный на стратегию Мартина Идена, является попыткой «вписаться» в наличный культурный мейнстрим. Выражено это в следовании поэтике соцреализма. Второй этап подспудно начинается с реабилитации отца Шукшина в 1956 года, когда актуализируется «гамлетовский комплекс», проявляющийся в чувстве вины перед отцом, через стратегию утаивания подлинного «я», мотивы чудаковатости. Третий этап связан с личностью реального исторического лица, Степана Разина, и выражается в открытом протесте против власти. Все важные для В.М. Шукшина поведенческие модели объединены мотивом одинокого противостояния враждебному социуму и имеют трагический финал, что обусловило ранний уход писателя и порождение мифов о насильственном характере его смерти. В.М. Шукшин одновременно был фигурой неординарной и типичной, что позволило его биографии стать «персональной моделью» для последующих авторов, выходцев из сельской глубинки. The article proposes the concept of life and creative growth of V.M. Shukshin through the prism of the thesaurus and cluster approach. The explanatory "personal models" for interpreting the biographical text of the writer are clusters of Martin Eden, Hamlet and Stepan Razin. Earlier, biographers and literary critics pointed out the importance of these people for Shukshin, but it was scattered. For the first time, an attempt was made to bring these personal models together into an integral plot of the formation of the writer in the space of culture. At different stages of the writer’s evolution, one of these models dominates, successively replacing each other, but not crowding out, but “overlapping”. The early stage of creativity, focused on Martin Eden’s strategy, is an attempt to “fit in” the current cultural mainstream. This is expressed in following the poetics of socialist realism. The second stage implicitly begins with the rehabilitation of Shukshin’s father in 1956, when the “Hamletian complex” is actualized. It is manifested in a sense of guilt towards his father, the strategy of concealing the true “I”, eccentricities. The third stage is connected with the personality of a real historical person, Stepan Razin, and is expressed in an open protest against the authorities. All important for V.M. Shukshin's behavioral models are united by the motive of a lonely confrontation with a hostile society and have a tragic ending, which led to the early departure of the writer and the generation of myths about the violent nature of his death. V.M. Shukshin was an extraordinary and typical figure at the same time. That allowed his biography to become a “personal model” for subsequent authors who came from the rural outback.


2021 ◽  
Vol 15 ◽  
pp. 159-164
Author(s):  
Fauzan Djamaluddin

In this study, the researcher carried out a comparative investigation of the crashworthy features of different tubular structures with a quasi-static three bending point, like the foam-filled two and tri circular tube structures. Energy absorption capacities and failure modes of different structures are also studied. Furthermore, the general characteristics are investigated and compared for instance the energy absorption, specific energy absorption and energy-absorbing effectiveness for determining the potential structural components that can be used in the field of vehicle engineering. Experimental results indicated that under the bending conditions, the tri foam-filled structures were higher crashworthiness behaviour than the two foam-filled circular structures. Therefore, this study recommended the use of crashworthy structures, such as foam-filled tri circular tubes due to the increased bending resistance and energy-absorbing effectiveness.


2020 ◽  
Author(s):  
Mohammed Mudassir ◽  
Mahmoud Mansour

Cellular materials such as metal foams are porous, lightweight structures that exhibit good energy absorption properties. They have been used for many years in various applications including energy absorption. Traditional cellular structures do not have consistent pore sizes and their behaviors and properties such as failure mechanisms and energy absorption are not always same even within the same batch. This is a major obstacle for their applications in critical areas where consistency is required. With the popularity of additive manufacturing, new interest has garnered around fabricating metal foams using this technology. It is necessary to study the possibility of designing cellular structures with additive manufacturing and their energy absorbing behavior before any sort of commercialization for critical applications is contemplated. The primary hypothesis of this senior project is to prove that energy absorbing cellular materials can be designed. Designing in this context is much like how a car can be designed to carry a certain number of passengers. To prove this hypothesis, the paper shows that the geometry is a key factor that affects energy absorption and that is possible to design the geometry in order to obtain certain behaviors and properties as desired. Much like designing a car, it requires technical expertise, ingenuity, experience and learning curve for designing cellular structures. It is simple to come with a design, but not so much when the design in constrained by stringent requirements for energy absorption and failure behaviors. The scope was limited to the study of metal foams such as the ones made from aluminum and titanium. The primary interest has been academic rather than finding ways to commercialize it. The study has been carried out using simulation and experimental verification has been suggested for future work. Nevertheless, the numerical or simulation results show that energy absorbing cellular structures can be designed that exhibit good energy absorption comparable to traditional metal foams but perhaps with better consistency and failure behaviors. The specific energy absorption was found to be 18 kJ/kg for aluminum metal foams and 23 kJ/kg for titanium metal foams. The average crushing force has been observed to be around 70 kN for aluminum and around 190 kN for titanium. These values are within the acceptable range for most traditional metal foams under similar conditions as simulated in this paper.


Author(s):  
Xilu Zhao ◽  
Chenghai Kong ◽  
Yang Yang ◽  
Ichiro Hagiwara

Abstract Current vehicle energy absorbers face two problems during a collision in that there is only a 70% collapse in length and there is a high initial peak load. These problems arise because the presently used energy-absorbing column is primitive from the point of view of origami. We developed a column called the Reversed Spiral Origami Structure (RSO), which solves the above two problems. However, in the case of existing technology of the RSO, the molding cost of hydroforming is too expensive for application to a real vehicle structure. We therefore conceive a new structure, named the Reversed Torsion Origami Structure (RTO), which has excellent energy absorption in simulation. We can thus develop a manufacturing system for the RTO cheaply. Excellent results are obtained in a physical experiment. The RTO can replace conventional energy absorbers and is expected to be widely used in not only automobile structures but also building structures.


Author(s):  
Sean Jenson ◽  
Muhammad Ali ◽  
Khairul Alam

Abstract Thin walled axial members are typically used in automobiles’ side and front chassis to improve crashworthiness of vehicles. Extensive work has been done in exploring energy absorbing characteristics of thin walled structural members under axial compressive loading. The present study is a continuation of the work presented earlier on evaluating the effects of inclusion of functionally graded cellular structures in thin walled members under axial compressive loading. A compact functionally graded composite cellular core was introduced inside a cross tube with side length and wall thickness of 25.4 mm and 3.048 mm, respectively. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, plateau stress level, and energy curves, were evaluated. The results showed that the inclusion of composite graded cellular structure increased the energy absorption capacity of the cross tube significantly. The composite graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the cross tube thus delaying local tube wall collapse and promoting large localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that were observed in the empty cross tube under axial compressive loading. The variation in deformation mode resulted in enhanced stiffness of the composite structure, and therefore, high energy absorption by the structure. This aspect has a potential to be exploited to improve the crashworthiness of automobile structures.


2020 ◽  
Vol 21 (4) ◽  
pp. 131-134
Author(s):  
O. G. Sivkov ◽  
◽  
A. O. Sivkov ◽  

Aim. To study urinary nitrogen excretion at the early stage of severe acute pancreatitis. Materials and methods. Prospective, single-center, cohort study. Inclusion criteria: diagnosis of acute pancreatitis and presence of at least one of the predictors of severe course. Among all patients (n = 72), a cohort of patients with severe acute pancreatitis (n = 32) was allocated. Three groups were formed in it: the first one – all patients, the second one – survivors (n = 24), the third one – deceased (n = 8). Urinary nitrogen excretion was determined using the Deacon formula. Measurements were performed on the first, third and fifth days of the disease. Statistical processing of the material was carried out by the SPSS software package. The null hypothesis was rejected at p < 0.05. Results. In the first week of the disease in all groups, the maximum urinary nitrogen excretion occurs on the 3rd day. When comparing the results of the second and third groups, it was found that the urinary nitrogen excretion on the first and fifth days did not have a statistically significant difference between the groups (respectively, p = 0.138, p = 0.572), and the results of the third day have (p = 0.014). A similar pattern remains when recalculating the nitrogen loss in the urine to the ideal weight; for the third day, the differences between the second and third groups were statistically significant (p = 0.007). ROC analysis of urinary nitrogen excretion of the third day calculated to the ideal body weight showed an area under the curve of 0.813 (p < 0.009). The value at the cut-off point is defined as 0.65 g/kg/day. The sensitivity of the model was 0.75%, specificity – 0.83%. Conclusion. If in a patient with acute pancreatitis, there is urinary nitrogen excretion on the third day from the onset of the disease, calculated to an ideal body weight of ≥ 0.65 g/kg/day, an unfavorable outcome of the disease is predicted.


1978 ◽  
Vol 76 (1) ◽  
pp. 105-122 ◽  
Author(s):  
ARTHUR W.M. ENGLISH

The patterns of activity of 33 forelimb muscles during unrestrained overground stepping in eight adult cats were analysed using intramuscular electromyography. Three general patterns were found. Some muscles began activity during the first extension epoch (E1) and ceased near the end of the third extension epoch (E3) and were considered extensors. Others, considered flexors, began activity just prior to the flexion (F) epoch and ceased at or just after the onset of E1. Other muscles showed a biphasic pattern of activation; one period of activity occurring during F, the other during the extension epochs. In all regions of the limb, individual muscles displayed variation in the onset and time course of activity. The results are interpreted in terms of a model of locomotor generation which proposes specific neural output to individual muscles. Muscles of the shoulder region are proposed to act mainly to produce translatory and rotatory movements of the scapula associated with lengthening the step. Muscles of the elbow region and antebrachium are interpreted as playing roles both in producing flexionextension movements and in the absorption of energy. The latter group are considered especially suitable to energy absorption because of their pennate arrangement of muscle fasciculi and their long tendons.


Sign in / Sign up

Export Citation Format

Share Document