Side Members Research Articles

LOAD-LOADING CAPACITY AND CRACK FORMATION OF REINFORCED CONCRETE CYLINDRICAL SHELL WHEN CHANGING ITS THICKNESS

The results of experimental studies of long cylindrical shells with the aim of determining their stress-strain state, load-bearing capacity and crack resistance when the thickness of the shell changes are described. A special stand was developed by the authors to implement the task. 4 models of a cylindrical shell made of reinforced concrete (samples RC1-RC4) were manufactured and tested. The thickness of the samples was 45, 50, 55, 60 mm, and the cross-sectional dimensions of the side elements were changed accordingly. The distributed load (vertical) was applied in four strips, each 13 cm wide, and only the body of the shell, i.e. the side members were not loaded. The shell hinges from the corners on 100x100mm plates. Inside each side element are two reinforcing rods with a diameter of 10 mm. In order to obtain a complete and reliable picture of the deformation of the shell surface, 4 hour-type indicators are attached to each of the three zones located between the load chains. In addition to indicators, strain gauges were pasted on the shell, which were used to monitor deformations on the upper and lower surfaces. The loading process ended when the tested shell lost its ability to resist the external load. The magnitude of the load corresponding to this moment was taken as the bearing capacity of the shell. Simultaneously with the shell samples, control samples of prisms and cubes were made to determine the physical and mechanical characteristics of concrete. Graphs of the dependence of the relative deformation on the load were constructed. The bearing capacity of the shells and the load at which the first crack formed were determined. By the time of loss of bearing capacity, cracks with the same initial opening width of 0.05 mm had formed in all shells. The final crack opening width, as well as the load-bearing capacity, slightly increased with increasing shell thickness. However, the load at the beginning of crack formation turned out to be the largest for the two average values of the shell thickness – 50 and 55 mm. The general pattern of cracking of all samples is almost the same. The test methodology and the developed stand are universal in nature and will be used for further research.

Determination of stresses in dangerous cross-sections of frame spars of minitractor vehicles

Problem. On the basis of the method of initial parameters, it is necessary to determine the mass-dimensional parameters of the frame of the spar type, for the creation of a universal small-sized vehicle UMTZ-26 "Nadia", as well as for the development of a mini-truck of category N1, with a carrying capacity of up to 3.2 tons. Goal. To determine the value of the maximum forces (stresses) and moments acting in the structural elements of the spar frame during the arrangement of the engine with transmission, body, engine compartment and cabin of the UMTZ-26 "Nadia" light vehicle, as well as units and aggregates of the N1 category, which can be used for municipal city or farm purpose. Results. According to the given calculation using the method of initial parameters (for frame structures), the maximum load in the cross section of the selected channel is determined, which does not exceed 106.372 MPa, the latter is used as a spar in the welded frame of the vehicle. The maximum permissible load that this profile of the channel can withstand is 160 MPa. Originality. The drawing and design documentation of the spar type was developed, which was used for the development of new universal small-sized vehicles of the UMTZ-26 "Nadia" type, as well as for the creation of mini trucks of the N1 category. Practical value. The practical value lies in the fact that the values of the maximum forces and moments acting in the side members of the frame when the engine with transmission, the engine compartment and the cabin of the vehicle are arranged on it do not exceed the maximum permissible values and the latter can be used on mini motor vehicles of category N1.

AISI 4130 and E250BR alloy steels chassis structural analysis and performance comparison

A base frame, also known as a skid and it is one of the most important parts of an automotive vehicle. It is a structural member made up of small cross members and long side members. Frame takes the entire load and vibration of the vehicle, so it should be strong enough. In this paper, the 3D modeling and analysis of ISMC C-section and ISMB I- section is caried out using Creo parametric software as per IS: 808.1989. There are four base frames developed (2 frame with C-section and 2 frames with I-section). E250BR and AISI 4130 alloy steel material are assigned to C and I-section base frames. The base frames are designed for a 40kN load capacity and load is uniformly distributed over the entire span of frame. Bending stress and deflection are calculated analytically as well as using FEA to determine strength of frames. For the deflection calculation, Macaulay’s method is used with both side overhang beams. The flexural rigidity equations are used to find the bending stress. Finally, the comparison of all base frames is done. Result shows that for the same load carrying capacity minimum deflection occur at ISMB I-section base frame. Also, stresses generated in I-section and C-section base frame for both materials are same. Material E250BR perform better than AISI 4130 alloy steel in deformation. So, performance of material E250BR is better than that of AISI 4130 alloy steel.

Effective Press Folding Line Processing as Deformation Induction for Adjusting Impact Energy Absorption

Press formed products have recently been applied widely in various structures. Press forming is a mass production method that is used to manufacture many machine components such as automobiles, industrial machinery, and various plants. However, there is a limit to the degree of shape freedom that can be applied, so measures against cracks, wrinkles, spring-back, etc., must be taken in the development process. It is well known that it is difficult to apply it economically in the case of small-lot production because of its high capital investment. The previous report shows that the folding line processing by press method / bending has a high degree of shape freedom, requires little capital investment, and can be expected to be applied for experiments and prototypes, and for commercial products from small to mass production. This paper shows that press folding line processing using V-shaped punch can be applied as deformation induction based on impact crushing experiments using square steel tubes/ aluminum thin wall cylinders and FEM results. To improve the impact energy absorption performance in the event of a collision, notches and uneven surfaces called beads have been formed in the crush boxes and front side members as automobile parts manufactured by press forming. The bead has the role of inducing deformation so as to improve the impact energy absorption performance during the axial crushing process. However, beads as deformation induction by the press forming, in addition to the difficulty of die design/manufacturing, needs to correct the bead design after impact experiments using prototypes. This paper shows press folding line processing as deformation induction is very convenient and effective to adjust impact energy absorption only by setting folding lines arrangement, not for bending along folding lines. Press folding line processing can be applied for the high performance crush box development.

変形誘発で衝撃エネルギー吸収を調節できるプレス折線加工の提案

Press forming is a mass production method that is used to manufacture many machine components such as automobiles, industrial machinery, and various plants. However, there is a limit to the degree of shape freedom that can be applied, so countermeasures against cracks, wrinkles, spring-back, etc., must be taken in the development process. It is well known that it is difficult to apply it economically in the case of small-lot production because of its high capital investment. In a previous report, the author reported that the folding line processing by press method / bending has a high degree of shape freedom, requires little capital investment, and can be expected to be applied for experiments and prototypes from small to mass production. This paper shows that press folding line processing using V-shaped punch can be applied as deformation induction based on experiments and FEM results. To improve the impact energy absorption performance in the event of a collision, notches and uneven surfaces called beads have been formed in the crush boxes and front side members as automobile parts manufactured by press forming. The bead has the function of inducing deformation so as to improve the impact energy absorption performance during the axial crushing process. However, bead setting for inducing deformation by the press forming, in addition to the difficulty of mold design/manufacturing, needs to correct the bead design after impact experiments using prototypes. This paper shows press folding line processing as deformation induction is very convenient and effective.

Optimization of the Cross-Member Thickness and its Effect of Torsional Rigidity

According to the tadpole design, the vehicle will have two wheels up front and one wheel in the back. Because it is a perfect fit between the motorcycle and automobile categories, the vehicle must adhere to both motorcycle and automobile laws. The purpose of this project is to design a full-scale chassis concept based on modern and future requirements and regulations. In addition to this, the chassis should have a reasonable price without sacrificing the overall quality of the design. It was estimated that cross-members with a thickness of 200 mm were the best option for increasing the chassis torsional rigidity, and the basis of the chassis is constructed out of frames. It was observed that the C-shaped side members on the chassis were not as robust as the tubular truss side members when subjected to the vertical stresses.

Experiment and design approach of steel-to-laminated bamboo lumber screwed connections under load parallel to grain

As a new type of green building material, laminated bamboo lumber (LBL) has attracted more and more attention in the field of civil engineering. Dowel connections is one of the most significant connection methods for LBL, in which screw has the advantages of low cost and simple installation. This paper experimentally investigates screwed connections with LBL as main members and steel plate as side members, in which the effects of screw diameter, anchorage depth, end distance, center-to-center distance and row distance are studied. 45 single-screwed connection specimens were tested by symmetrically configured lateral resistance tests and 2 failure modes of screw pull-out and screw cut-off were observed, corresponding to 2 yield modes of screws. 18 double-screwed connection specimens were tested to propose design recommendations to avoid brittle failure between screw holes in LBL. Then the test results were compared with the predicted values calculated by NDS-2018, Eurocode 5 and GB/T 50005-2017. Based on the assumption of ideal elastoplastic model, a theoretical formula was derived and verified by test results. Besides, experimental load-slip curves were compared with those of Foschi model, which showed that Foschi model can be used to predict load-slip curves under the appropriate relative stiffness between fasteners and members. This research provides a scientific basis and favorable information for the engineering design and applications of LBL structures with screwed connections.

Experimental and numerical investigation on the multi-optimization of reinforcing the side members of the vehicle structure

The aim of this study is to investigate the improvement in the strength of a top-hat profile hollow-section beam used in a vehicle structure by attaching different shapes of internal reinforcements. The base structure of the beam was first considered as a hat-shape structure which was jointed to a flat plate using spot-welds. Three types of sheet metal reinforcements were formed and attached inside the beam’s structure. Then, they were tested experimentally under low-velocity lateral impact. Also, a numerical simulation is being developed using LS-DYNA explicit code and validated using experimental data. Valid numerical configuration is used to conduct an optimization study on cross-sectional shape of the internal reinforcing component. Optimizations are carried out using single- and multi-objective methods based on Genetic Algorithm approach and the suggested optimum solutions are compared with experimental results. Moreover, to discuss the feasibility of applied reinforcements on side section of a vehicle’s body-in-white, a realistic side-pole crash test is simulated using a validated vehicle model and performance of improved chassis is compared with basic model and results are presented, discussed and commented upon.

Simulation and Optimization of Body Structure of Electric Vehicles with Offset Collision

In recent years, as the rapid growth of the number of electric vehicles, people have more and more requirements on the safety performance of vehicles. However, compared with fuel vehicles, the structure of electric vehicles has its own particularity which makes the safety design of body structure more difficult. Thus, improving the passive safety of electric vehicles and protecting the passengers from injury in the collision to the greatest extent have become important issues for the automotive industry. This paper simulates the frontal offset impact simulation analysis of a certain type of SUV, and analyzes the safety performance of the vehicle from the perspective of member protection. The front side member structure and impact energy absorption which affect the passive safety of the whole vehicle are optimized and improved. The finite element model of the whole vehicle is rebuilt, and the frontal offset impact simulation test is carried out to verify the effectiveness of the optimization scheme.

Structural performance of laminated-bamboo lumber nailed connection

ABSTRACT The aim of this paper was to provide a better understanding of the mechanical behaviour of laminated-bamboo lumber nailed connection loaded monotonically. The specimens varied in nail diameter, edge distance of nail and loading angle to the grain. For edge distance less than six times the nail diameter (6d), the specimens failed prematurely at a lower load and exhibited moderate ductility behaviour. Two plastic hinges formed inside the side and core members, with crushing of the laminated bamboo lumber fibres, if the minimum construction requirements of nail edge distance were satisfied. It is found that the load increases significantly with the increase of nail diameter. Reductions in load-carrying capacity are witnessed with the increase in loading angle to grain, but the influence is small. The experimental results, such as stiffness and yield load, are compared against those predictions obtained from the existing design standards. A two-parameter theoretical model, related to the initial stiffness and yield load, is suggested to characterise the load-slip relationship of LBL nailed connections loaded monotonically, with the aim of deriving a mathematical relationship to represent this behaviour. There is a good agreement between the curves predicted by the theoretical model and the experimental results.

탄소섬유복합재와 강재의 재질과 형상변화에 따른 구조부재의 압궤 특성

In the event of a vehicle collision, the kinetic energy of the colliding vehicles can cause sever injuries to the passengers if the vehicle body is too strong and the passengers bounced out of the vehicle due to inertia. If the vehicle body absorbs considerable collision energy, the passengers might get trapped inside, causing their death. Therefore, when a vehicle crashes, the structural members of its body must efficiently absorb the collision energy and secure space. In this study, a single hat-shaped cross-section member and a double-hat cross-section member has been used for the side member of an automobile that absorbs most of the collision energy during a vehicle collision event. Following the designing and manufacturing of the steel and carbon fiber reinforced polymer (CFRP) material structural members, the axial collapse test was performed to investigate the collapse mode and energy absorption characteristics based on their shape and material changes.

Friction characterization and application to warm forming of a high strength 7000-series aluminum sheet

Tribological conditions are challenging when forming high strength aluminum alloys at elevated temperatures due to the sticking behavior of aluminum and potential material transfer to the die in the form of die pick-up. The current study examines the elevated temperature performance of several lubricants as well as a Physical Vapor Deposition (PVD) die coating, in conjunction with a 7000-series aluminum alloy sheet under conditions corresponding to warm forming of automotive structural components. Lubricant performance is characterized from the coupon-to-component level at temperatures in the range of 25–230°C. The classical coupon-level Twist Compression Test (TCT) is modified to perform elevated temperature experiments and used to rank the lubricants in terms of their steady-state coefficient of friction and resistance to lubricant breakdown as a function of temperature. It is found that both the friction coefficient and lubricant breakdown distance need to be considered for lubricant assessment. The studied PVD die coating is found to successfully mitigate lubricant breakdown for the FORGE EASE AL 278 at 230°C in the TCT. In parallel, warm forming experiments considering deep drawn cylindrical cups and U-channel rail sections (representative of a structural side member) are used to evaluate lubricant performance under real stamping conditions. The trends in forming performance (draw-in length, final blank perimeter, visual scoring, and forming force) confirm the lubricant ranking obtained from the TCT coupon tests, with the Teflon® PTFE film as the most effective followed by the FORGE EASE AL 278, OKS 536, and the LPS® Dry Film PTFE Spray Lubricant. For the highest test temperature, the LPS® Dry Film PTFE Spray Lubricant exhibits breakdown in the TCT at short sliding distances and results in fracture during deep drawing.

The impact behavior of the crash boxes

This article will study the impact behavior of the crash box structures. The crash boxes are found between the front cross member and the front side members. They play an important role in case of minor frontal impact, speeds up to 15km/h. For this study, we propose three models of crash boxes of different sections. The impact analysis will be performed using the software ANSYS, Explicit Dynamics module. The shape and dimensions of the models were obtained from repeated impact tests. Thus, the obtained results were used for the continuous improvement of the crash boxes. The proposed models are made from extruded Aluminum bars with different sections. With the help of finite element analysis (FEM) one can compare the results and what impact energy absorption characteristics each proposed model of structure presents.

A framework for quantifying controversy of social network debates using attributed networks: biased random walk (BRW)

All societies have been much more bipolar over the past few years, particularly after the emergence of online social networks and media. In fact, the gap between the two ends of social spectrum is going to be even deeper after the spread of new media. In this circumstance, social polarization has been a growing concern among socialists and computer science experts because of the detrimental impact which online social networks can have on societies by adding fuel to the fire of extremism. Several types of research were conducted for proposing measures to calculate the controversy level in social networks, afterward, to reduce controversy among contradicting viewpoints, for example, by exposing opinions of one side to other side's members. Most of the attempts for quantifying social networks' controversy have considered the networks in their most primary forms, without any attributes. Although these kinds of researches provide platform-free algorithms to be used in different social networks, they are not able to take into account a great deal of useful information provided by users (node attributes).To surmount this shortcoming, we propose a framework to be utilized in different networks with different attributes. We propelled some Biased Random Walks (BRW) to find their path from start point to an initially unknown endpoint with respect to initial energy of start node and energy loss of nodes on the path. We extracted structural attribute of networks, using node2vec, and compared it with state-of-the-art algorithms, and showed its accuracy. Then, we extracted some content attributes of user and analyze their effects on the results of our algorithm. BRW is compared with another state-of-the-art controversy measuring algorithm. Then, its changes in different level of controversy in Persian Twitter is considered to show how it works in different circumstance.

Research on influence of Web spacing of bogie side member on welding deformation

In the production process of bogie, welding is one of the important production technologies. To study and control the welding deformation of bogie frame side beam to make the deformation value within a reasonable range has very important practical significance for the production of bogie side beam. The research content of this paper will take high-speed EMU bogie frame side beam as the research object. Set different web spacing, compare the welding deformation value, explore the influence of structural stiffness on the welding deformation of side beam, and use MATLAB software to curve fitting the welding deformation value, the research shows the distribution law of transverse, longitudinal, vertical and comprehensive welding deformation, and fits the mathematical equation between the web spacing L and longitudinal deformation SX, vertical deformation SY, transverse deformation SZ In this paper.

Experiments on laminated bamboo lumber nailed connections

Laminated bamboo lumber (LBL) nailed connection made with LBL main member and sandwiched by LBL side members is introduced, which plays an essential role in the safe and reliability of bamboo buildings. However, little research attention has been paid on to the mechanical behavior of connections. This paper reports an experimental study on the effect of parameters on reference loads (yield load and maximum load), stiffness and load-slip behavior of the connections, including nail diameter, number of lines and rows of nails. For single nail connection, nail pull-through and plastic hinges forms in LBL members. Mode cross-over from ductile response to brittle failure is observed in multi-nail connections with one or more splitting cracks develop from the nails hole edges toward the ends of the side or middle members. A decreasing ductility of connections is investigated with increasing diameter and number of nails. The capacity of effective number of nails in a row is evaluated and compared with that obtained from existing analytical formulas. Predictions from existed various theoretical modes are compared with experimentally determined capacities of nailed connection per shear plane per nail and conclude that the load carrying capacity of connections with laterally load nails can be applied to accurately estimate using European yield models (EYMs). Furthermore, the model developed by Folz is capable of predicting the load-slip relationship of LBL nailed connections. The findings of this study will provide the scientific basis and useful information for the design and finite element numerical simulation of engineered bamboo structures containing LBL nailed connections and promote the rational use of bamboo resources in the field of civil engineering.

ERGONOMIC ASPECTS RELATED TO MOBILE AGRICULTURAL MACHINERY OPERATORS

Ergonomics is the key to make the machine “worker friendly”. In this paper, the humble effort is carried out to present the outline of the tractor industry of India as well as Ukraine for the subsequent analysis of the operator's working conditions and negative production factors that affect his health. Experiment was conducted in Ukraine for three different tractor models i.e. HTZ-181, HTZ-200, HTZ-200B. Vibrations were measured at frame between cab brackets (on left side member), cab floor at the operator's feet and cab frame (on rear crossmember at the rear window base) for plowing and harrowing operations. Research of structural elements vibration parameters of some tractor models (for harrowing and plowing operation) showed that the cab frame has the highest vibration activity in the vertical direction with a peak in the octave band with a geometric mean frequency of 16 Hz. In the transverse direction, the tractor frame has the highest vibration acceleration amplitude, while the maximum vibration acceleration amplitude falls on the octave band of 16 Hz, but its value is two times lower than in the vertical direction. It was also observed that the amplitudes of vibration accelerations of the elements of the tested tractors during plowing the field had higher values than during harrowing, but these excesses were not significant. Analysis of the test results shows that the tractors' suspensions have practically the same vibration characteristics, and therefore, it is recommended to conduct further studies of the parameters of general vibration (on the operator's seat) and local vibration (on the steering wheel) in order to assess the tractor operator' working conditions, his safety and develop technical solutions to improve the devices/machines. The study practical value and originality consists in identifying the structural elements of mobile agricultural machinery (for example, tractors) that have the highest vibrations, which affect the operator for their further improvement, but not for replacing the machinery. This approach to improving the working conditions of mobile agricultural machinery operators is driven by the country's weak economy and can be beneficial for developing countries in the face of a lack of funds to purchase new ergonomic machines.

Static Tests of Wing Box of Composite Aircraft Wing Using Acoustic Emission and Strain Gaging

Static tests of a two-spar T800 CFRP wing box have been carried out. The object was tested when loaded using the methods of acoustic emission (AE) and strain gaging. Strain in the material was determined in real time in the areas where strain gages were bonded (the panels of wing box, the walls of side members, and the shelves of stringers). The elements of the wing box have been established in which nonlinear strain change is observed and residual deformations are recorded after unloading. The AE method has been used to localize the sources of signals. The coordinates of the sources corresponded to the location of the third rib. Clustering recorded AE signals based on their digitized form has made it possible to group the signals and assign them to sources that correspond to structure failure. It is shown that in the process of loading the wing box, an increase in the structural coefficient of AE signals corresponding to CFRP delamination in the location zone is observed.

A Research on Reducing the Weight of Semi-Trailer Frame Manufactured in Vietnam

This article analyses and proposes suitable approaches to improve frame structures in term of weight reduction for heavy-duty truck chassis frame in general and semi-trailer frame in particular. Specifically, this study focused on reducing the weight of frame side members, which makes up the primary mass of the vehicle chassis. Some variants of design to evaluate its efficiency and applicability on semi-trailer frame were proposed. The study explored maximum stress and deformation within the frame structure under static loading conditions using the integrated finite element analysis and multi-body simulation based on which some modified designs from the existing frame was proposed to reduce the weight of the chassis frames, including altering the main beam's material property, cross-section dimension, or lightening holes. The analysis results were presented in plots of the stress and deflection spectrum of the frame in numerical simulations. The proposed approaches were analysed and discussed to find out the appropriate improvement method for the heavy truck frame and the semi-trailer frame suitable for the truck manufacturers in Vietnam.

FRONT AND SIDE IMPACT ANALYSIS OF SPACE FRAME CHASSIS OF FORMULA CAR

One of the popular types of formula car chassis is space frame chassis. There are many issues to design and analyze formula car chassis. For driver, Front and side impact are the main issue for design and analysis with accurate and safety. In this article, the 2017-2018 formula SAE (the Society of Automotive Engineers) rules are used for analysis. SolidWorks 2016 are used to construct the CAD models of formula car chassis. Finite element method (FEM) is used to analyze the CAD models using SolidWorks Simulation. The results show that all formula car chassis models satisfy the 2017-2018 formula SAE rules. For the front impact, the maximum stress and the maximum deflection are not significant affected by varying the distance of the side members. While varying the distance of the front impact members affects both of the maximum stress and the maximum deflection. For the side impact, the maximum stress and the maximum deflection are not significant affected by varying the distance of the front members. While varying the distance of the side members affects both of the maximum stress and the maximum deflection. The criterions of the formula car chassis design are to make maximum stress lowest and maximum deflection lowest. The distance of the front members joint and the distance of the side member joint should be as low as possible.