scholarly journals Improving safety and reliability of Gazelle series vehicles by upgrading frame structures

2020 ◽  
pp. 39-44
Author(s):  
M. S. Dolmatov ◽  
◽  
S. A. Ivanov ◽  
A. G. Isaev ◽  
◽  
...  
Keyword(s):  
Load Capacity ◽  
High Strength ◽  
Technical Condition ◽  
The Body ◽  
High Tech ◽  
Passenger Cars ◽  
Load Bearing ◽  
Light Duty ◽  
Wide Range ◽  
Lap Welding

Introduction. The cargo frame is a load-bearing element of the car, since the body and chassis are installed on it. Therefore, high strength requirements are imposed on this node. For safe and reliable operation of the truck, the frame must be adjusted and balanced, since even minor changes in the geometry can negatively affect the overall condition and safe operation of the equipment. This article discusses methods for lengthening the load-bearing elements of trucks on the example of a light-duty car "GAZelle". Problem Statement. Car frame extension is a high-tech process that requires high precision, knowledge, and the use of a wide range of equipment. The extended frame adds a number of advantages to the car, which in turn makes it possible to transport cargo with larger dimensions. The main goal of this work is to enable the car to transport bulky cargo. Also, in the process of extending the frame, it is checked for cracks, breaks and corrosion foci and, if necessary, repairs are made, which increases the reliability, safety and service life of the entire structure as a whole. Theoretical Part. When extending the standard support, all attachments are removed from the car: fuel tanks, body, transmission, drive shaft. All that remains is the cab, the bridge, and the engine. Then the frame is cut in three places. Two cuts are made at a distance of 80 cm in the direction from the cab to the rear bridge, and the last one is made at a distance of 40 cm from the rear bridge in the direction of the rear overhang. Then a longer channel is installed on the frame. It is secured with rivets, bolts, or lap welding. After that, the structure is assembled back. This takes into account the redistribution of loads and the need for high-quality performance of all types of work. Conclusion. The frame is an integral part of not only trucks, but also an important component of passenger cars, as well as light-duty vehicles. Its technical condition is just as important as the condition of, for example, the braking system, as it also ensures the safety of both the driver and pedestrians. The lengthening of the frame in the conditions of repair and mechanical enterprises allows you to increase the load capacity of serial cars of the GAZelle series while ensuring their reliability and safety.

Investigation of the interaction of car wheels with the stand rollers during braking

2021 ◽  
Vol 13 (1) ◽  
pp. 68-77
Author(s):  
Igor Мarmut ◽  
◽  
Andriy Kashkanov ◽  
Vitaliy Kashkanov ◽  
◽  
...  
Keyword(s):  
Traffic Safety ◽  
Technical Condition ◽  
The Body ◽  
Power Model ◽  
Equilibrium Equations ◽  
Design Features ◽  
Complex Objects ◽  
Passenger Cars ◽  
Wheel Drive ◽  
Four Wheel Drive

The article discusses the issues of modeling conditions for obtaining diagnostic information about complex objects. As an example, the study of the braking qualities of four-wheel drive cars on an inertial roller stand is considered. Diagnosing the technical condition of cars from the point of view of traffic safety is one of the most important problems. This is especially important for systems whose technical condition affects traffic safety: especially braking systems. Foreign and domestic experience testifies to the effectiveness of instrumental control. The diagnostic equipment includes roller stands, on which you can check the braking properties of cars. As shown by many studies, in particular, carried out at the Department of Technical Operation and Service of Automobiles, KhNADU (HADI), inertial stands provide more reliable information about the technical condition of the car. Such stands allow you to reproduce the real speed and thermal modes of the brakes (especially those equipped with ABS). To improve the accuracy of diagnosing a car on a roller stand, it is necessary to have an idea of the nature of the interaction of the car wheels with the rollers. The studies of wheel rolling on the stand rollers have been carried out by many authors since the 80s of the last century. However, all these studies were carried out on uniaxial stands and for mono-drive vehicles. Nowadays, a large number of passenger cars have four-wheel drive. Rolling of the wheels of such cars on rollers and their interaction has practically not been studied. Therefore, a return to the study of this issue is relevant. A power model of the system of interaction between the car and the stand has been developed, taking into account the design features of the stand and the design features of the car's suspension. The power model of the system under consideration contains the equilibrium equations of the body and two bridges and the equations of motion of the rollers and wheels of the car. Based on the results of the analysis of the acting forces in the "car-stand" system, the braking moments on the wheels M and the coefficients of the use of the load q during the braking tests of a 4x4 vehicle were determined. The obtained research results allowed to improve the theory of interaction of a car wheel with the rollers of an inertial diagnostic stand.

Optimization of Pneumatic Vibration Isolation System for Vehicle Suspension

1978 ◽  
Vol 100 (3) ◽  
pp. 500-506 ◽  
Author(s):  
E. Esmailzadeh
Keyword(s):  
Vibration Isolation ◽  
Load Capacity ◽  
Damping Ratio ◽  
Optimization Technique ◽  
Suspension System ◽  
The Body ◽  
Vehicle Suspension ◽  
Design Data ◽  
General Outline ◽  
Wide Range

The suspension system of a vehicle provides the means by which forces and movements are transferred from the body to the wheels and vice versa. While the general outline of vehicle suspension behavior is fairly well known, little interest has been shown in the detailed dynamic performance of the various components. Air springs are perhaps the most versatile and adaptable type of suspension element. They provide practically frictionless action, adjustable load capacity and simplicity of height control. Initially, a vehicle suspension system with a pneumatic isolator connected to a fixed volume tank via parallel plate restrictor is considered. Here the damping is provided by the flow of air through the restricted passage which has an advantage over the conventional viscous shock absorber. Body movements are only considered to be vertical harmonic displacement. An optimization technique is applied to evaluate the optimum values of many parameters involved for which the maximum transmitted motion to the body would be minimum over the broad frequency range. Theoretical expressions for the transmissibility of the body and the wheel, optimum values of mass ratio, stiffness ratio and damping ratio are presented. Design data are presented nondimensionally for parameter variations which are sufficiently broad to encompass a wide range of practical engineering problems.

scholarly journals ЭКСПЕРИМЕНТАЛЬНОЕ ОПРЕДЕЛЕНИЕ ОСТАТОЧНОЙ ПРОЧНОСТИ ЭЛЕМЕНТОВ КОНСТРУКЦИЙ ПАРАШЮТОВ, ИСЧЕРПАВШИХ ЗАДАННЫЙ СРОК ЭКСПЛУАТАЦИИ

2019 ◽  
pp. 80-87
Author(s):  
Кирило Вікторович Миронов ◽  
Євген Федорович Кучерявий
Keyword(s):  
Compressive Force ◽  
High Strength ◽  
Technical Condition ◽  
Suspension System ◽  
Structural Elements ◽  
Design Elements ◽  
Textile Materials ◽  
Wide Range ◽  
Speed Up ◽  
Working Section

To make a decision on determining the periods of safe operation of parachute systems that have exhausted a given resource, it is necessary to know the parameters of their actual technical condition. Experimental destructive methods for determining the parameters of residual strength are considered: breaking strength and relative deformations during the breaking of the standard specimens.Parachute design elements to be examined include parachute dome fabrics, carcass reinforcement ribbons, strops, and suspension system belts. In order to ensure that all requirements set forth by regulatory documents for conducting an experiment with textiles, specialized devices have been developed, designed, manufactured and tested experimentally. These devices provide strength experiments on a universal tensile machine designed to work with samples of metallic materials.The need to create specialized devices is caused by a very wide range of braking forces (from tens to several thousand newtons), as well as by the specifics of synthetic textile materials of the parachute design elements. A set of devices has been developed that provide the required conditions for conducting rupture experiments on samples of textile materials. The created devices provide sufficient compressive force of the sample in the clips without slip-page and without violating the integrity of the contact surface of the studied synthetic textile materials. Ensuring that the sample is sufficiently compressed in the clamping devices of the tearing machine is ensured by special transitional gaskets and methods for creating a compressing force on the sample. Compressing devices and devices for conducting experiments with low-strength specimens of the dome fabric, with medium-strong reinforcing skeleton tapes, strops and high-strength straps of the suspension system are created. In order to speed up the preparation of samples for the experiment, methodologies have been created that ensure the required length of the working part of the sample and its fixation without warps. A universal strain gauge was developed to determine the change in the length of the working section of the specimen in 100 mm. Installing the meter on the sample under study allows you to measure displacements up to rupture. The meter is fastened to the specimen using spring clips. The developed devices were tested during the experiment with hundreds of samples of the structural elements of 3 parachutes.

Hydroxyapatite Coating Improves Bone Integration and Interface Strength of Polymer Implants in Bone

2008 ◽  
Vol 396-398 ◽  
pp. 331-335
Author(s):  
Joerg Brandt ◽  
M. Pfennig ◽  
Christian Bieroegel ◽  
Wolfgang Grellmann ◽  
Anke Bernstein
Keyword(s):  
Mechanical Properties ◽  
Hip Joint ◽  
Femoral Stem ◽  
The Body ◽  
Polymer Materials ◽  
Metal Alloys ◽  
Load Bearing ◽  
Natural Bone ◽  
Wide Range ◽  
Joint Prostheses

Many attempts had been made to improve the durability of artificial joint replacement and other orthopaedic implants by approaching the mechanical properties of bone and artificial material. The most joint prostheses used today are manufactured of metal alloys based on cobalt, chromium or titanium. The mechanical stiffness of these materials is much higher than that of natural bone resulting in adverse effects such as local overloading on one hand or stress shielding phenomena with the lack of adequate mechanical load on the other. Both mechanisms contribute to earl loosening and failure of implants. Polymer materials may deliver mechanical properties very similar to bone and their mechanical behaviour may be modified in a wide range during the process of manufacturing. First attempts to lower the stiffness of the implant material and to gain the stiffness range of natural bone were made in the seventies by R. Matthys with his concept of “isoelastic hip prosthesis”. In this prosthesis the femoral stem was manufactured of polyacetal, a thermoplastic polymer with very good biocompatibility and elastic properties which are much nearer to bone than common metal alloys. While the prosthesis showed good results during the mechanical testing the clinical use in vivo became a disaster. Shortly after implantation polyacetal was degraded in the body and broke down under the immense loading of the human hip joint. Later attempts to use polymer materials alone for load bearing implants also failed in clinical practice over a long time because the mechanical interlocking between bone and implant was not sufficient for the biological demand. To make the outstanding properties of polymer materials useable for load bearing implants they are backed with metal alloys (as polyethylene for hip joint cups) until the presence. Only recent developments of polymer science succeeded in the use of polymers for loaded implants. One of the most interesting materials seems to be the polyetheretherketone (PEEK) which is successfully used for spinal fusion cages [2] and computerdesigned individual implants for defect reconstruction in the skull [4] meanwhile. A pre-clinical study of a new anatomically shaped flexible acetabular cup reported satisfactory results recently [3].

Comparative Effects of High-Tech Visual Scene Displays and Low-Tech Isolated Picture Symbols on Engagement From Students With Multiple Disabilities

2019 ◽  
Vol 50 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Christine Holyfield ◽  
Sydney Brooks ◽  
Allison Schluterman
Keyword(s):  
Language Learning ◽  
Augmentative And Alternative Communication ◽  
Visual Analysis ◽  
Multiple Disabilities ◽  
Visual Scene ◽  
Future Research ◽  
High Tech ◽  
Single Subject ◽  
Wide Range ◽  
The Difference

Purpose Augmentative and alternative communication (AAC) is an intervention approach that can promote communication and language in children with multiple disabilities who are beginning communicators. While a wide range of AAC technologies are available, little is known about the comparative effects of specific technology options. Given that engagement can be low for beginning communicators with multiple disabilities, the current study provides initial information about the comparative effects of 2 AAC technology options—high-tech visual scene displays (VSDs) and low-tech isolated picture symbols—on engagement. Method Three elementary-age beginning communicators with multiple disabilities participated. The study used a single-subject, alternating treatment design with each technology serving as a condition. Participants interacted with their school speech-language pathologists using each of the 2 technologies across 5 sessions in a block randomized order. Results According to visual analysis and nonoverlap of all pairs calculations, all 3 participants demonstrated more engagement with the high-tech VSDs than the low-tech isolated picture symbols as measured by their seconds of gaze toward each technology option. Despite the difference in engagement observed, there was no clear difference across the 2 conditions in engagement toward the communication partner or use of the AAC. Conclusions Clinicians can consider measuring engagement when evaluating AAC technology options for children with multiple disabilities and should consider evaluating high-tech VSDs as 1 technology option for them. Future research must explore the extent to which differences in engagement to particular AAC technologies result in differences in communication and language learning over time as might be expected.

Theoretical study of the prestressing strand's stress by computer modeling methods

2020 ◽  
Vol 76 (11) ◽  
pp. 1139-1148
Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik
Keyword(s):  
Residual Stresses ◽  
High Strength ◽  
Pearlitic Steel ◽  
Internal Stresses ◽  
Steel Microstructure ◽  
Compressive Stresses ◽  
Wide Range ◽  
Prestressing Strands ◽  
Increasing Temperature ◽  
Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

Creating the Wind

2020 ◽  
Vol 2 (4) ◽  
pp. 14-31
Author(s):  
Élodie Dupey García
Keyword(s):  
Indigenous Communities ◽  
The Body ◽  
Historical Sources ◽  
Natural Behavior ◽  
Sensory Experiences ◽  
Identity And Agency ◽  
Wide Range ◽  
Late Postclassic ◽  
Comparative Examination ◽  
Meteorological Phenomenon

This article explores how the Nahua of late Postclassic Mesoamerica (1200–1521 CE) created living and material embodiments of their wind god constructed on the basis of sensory experiences that shaped their conception of this divinized meteorological phenomenon. In this process, they employed chromatic and design devices, based on a wide range of natural elements, to add several layers of meaning to the human, painted, and sculpted supports dressed in the god’s insignia. Through a comparative examination of pre-Columbian visual production—especially codices and sculptures—historical sources mainly written in Nahuatl during the viceregal period, and ethnographic data on indigenous communities in modern Mexico, my analysis targets the body paint and shell jewelry of the anthropomorphic “images” of the wind god, along with the Feathered Serpent and the monkey-inspired embodiments of the deity. This study identifies the centrality of other human senses beyond sight in the conception of the wind god and the making of its earthly manifestations. Constructing these deity “images” was tantamount to creating the wind because they were intended to be visual replicas of the wind’s natural behavior. At the same time, they referred to the identity and agency of the wind god in myths and rituals.

SP 700

Alloy Digest ◽  
1995 ◽  
Vol 44 (6) ◽  
Keyword(s):  
High Strength ◽  
Heat Treating ◽  
Bend Strength ◽  
Beta Titanium Alloy ◽  
Superplastic Behavior ◽  
Temperature Performance ◽  
Beta Titanium ◽  
Wide Range ◽  
Alpha Beta ◽  
Cold Workability

Abstract SP 700 is a high strength, beta-rich alpha-beta titanium alloy. It was developed with the following attributes: (1) excellent hot- and cold-workability; (2) enhanced hardenability with a wide range of mechanical properties that can be obtained by heat treatment; and (3) superior superplastic behavior at low temperature (around 1050 K). This datasheet provides information on composition, physical properties, microstructure, elasticity, tensile properties, and bend strength. It also includes information on high temperature performance as well as heat treating. Filing Code: TI-107. Producer or source: NKK Corporation.

STRENX 700

Alloy Digest ◽  
2017 ◽  
Vol 66 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
Tensile Properties ◽  
High Strength ◽  
Load Bearing ◽  
Minimum Yield

Abstract Strenx 700 is a high-strength structural steel with a minimum yield strength of 650–700 MPa (94–102 ksi) depending on thickness. Strenx 700 meets the requirements of EN 10 025-6 for the S690 grade and thicknesses. Typical applications include demanding load-bearing structures. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as forming, machining, and joining. Filing Code: SA-779. Producer or source: SSAB Swedish Steel Inc..

ALMAR 300 ALLOY

Alloy Digest ◽  
1978 ◽  
Vol 27 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Elevated Temperature ◽  
Cold Working ◽  
High Strength ◽  
Heat Treating ◽  
Age Hardening ◽  
Ultra High Strength Steel ◽  
Wide Range ◽  
Iron Nickel ◽  
Useful Yield

Abstract ALMAR 300 Alloy is a vacuum-melted ultra-high-strength steel. The annealed structure of this alloy is essentially a carbon-free, iron-nickel martensite (a relatively soft Rockwell C 28) that can be strengthened by cold working and elevated-temperature (900-950 F) age hardening to useful yield strengths as high as 300,000 psi. The unique properties of this alloy make it suitable for a wide range of section sizes. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-349. Producer or source: Allegheny Ludlum Corporation.

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