Application of the parallelogram mechanism with the effect of quasi-zero stiffness in the vibration protection systems of the operator’s chair of a road construction machine

For vibration protection of operators of construction and road machines, a promising direction is the use of passive vibration protection systems based on mechanisms with quasi-zero rigidity. Passive vibration isolation systems, being less complex than active ones, require less frequent maintenance, are cheaper to manufacture and more reliable than active ones. The problem of selecting the optimal, most reliable and simple design of the mechanism with the effect of quasi-zero rigidity remains urgent. In this case, the most widespread use of elements that create negative stiffness. This requires elements with positive stiffness in the mechanism, which complicates the design. More promising structures of mechanisms, where elements with negative stiffness are not separated into a separate structure. In mechanisms such as the parallelogram, studied in this work, a section with quasi-zero stiffness can be provided with just one tension spring, which simplifies the design and reduces the cost of the entire vibration protection system. By the method of direct analytical inference for the presented diagram of a parallelogram mechanism with one spring, analytical expressions are obtained for the tensile force of the spring necessary to compensate for the force of gravity of the chair with the operator on the height of the chair and the length of the spring. As an example, the graphical dependences of the spring tensile force on the chair lift and on the spring’s own length are given as an example. It was found that the static force characteristic of the spring is a straight line passing through the origin. That is, the zero force corresponds to the zero spring length, which is not technically feasible. It is proposed to use a mechanism that replaces the tension spring, which will provide a given power characteristic.

The spring bounces back: introducing the strain elevation tension spring embedding algorithm for network representation

This paper introduces the strain elevation tension spring embedding (SETSe) algorithm. SETSe is a novel graph embedding method that uses a physical model to project feature-rich networks onto a manifold with semi-Euclidean properties. Due to its method, SETSe avoids the tractability issues faced by traditional force-directed graphs, having an iteration time and memory complexity that is linear to the number of edges in the network. SETSe is unusual as an embedding method as it does not reduce dimensionality or explicitly attempt to place similar nodes close together in the embedded space. Despite this, the algorithm outperforms five common graph embedding algorithms, on graph classification and node classification tasks, in low-dimensional space. The algorithm is also used to embed 100 social networks ranging in size from 700 to over 40,000 nodes and up to 1.5 million edges. The social network embeddings show that SETSe provides a more expressive alternative to the popular assortativity metric and that even on large complex networks, SETSe’s classification ability outperforms the naive baseline and the other embedding methods in low-dimensional representation. SETSe is a fast and flexible unsupervised embedding algorithm that integrates node attributes and graph topology to produce interpretable results.

Design on Spaceborne Three Orthotropic Thin-Wall Tubular Antennas Deployment Mechanism

The purpose of spaceborne three orthotropic thin-wall tubular antenna is for space science probe which consists of three orthotropic tubular antennas. Three orthotropic thin-wall tubular antennas deployment mechanism is designed which consists of upper plate, lower plate, reel, burn-wire and tension spring. Flattened antenna tube can be wound in a reel which can be hold-down and locked by Dyneema string. Release by giving current to resistor, the string will melt while its temperature reaches its burning point, then the upper plate will be pulled up and the antennas can be deployed by stored strain energy in itself. According to a certain project requirements three orthotropic thinwall tubular antennas mechanism prototype was developed and tested, antenna tube was broken due to “blossom” phenomenon in deployment process. For avoiding “blossom” during deployment of antennas mechanism, the flange of reel is improved, so antennas can be deployed smoothly. Compared to motor-driven antenna mechanism, this antennas deployment mechanism has advantages of simple structure, lower mass and lower power consumption.

Preparation and characterization of silicone rubber with high modulus via tension spring-type crosslinking

“Tension spring-type crosslinking” for improving the modulus of silicone rubber.

Secondary Development of Marc Software Based on Shield Tunnel Load Structure Method and its Verification

Load structure method is commonly used in tunnel design; there are two problems for its implementation in Marc software: first, the force cannot be applied directly in Marc; second, the position of the spring around the tunnel is unknown. In view of first problem, by means of force conversion, a subroutine programming with Fortran is adopted to exert the force. For the second problem, iterative algorithm is adopted; the tension spring will exit calculation, and a comparison of the spring position in the two steps will be made, if the position is the same, the computation will finish. The work above realizes the Load structure method in Marc software and enlarges the application of Marc software in underground engineering. The verification example is given to prove the validity of the interface subroutine.

Study on Tension Spring of Track Hydraulic Drill Rig

The intensity of the spring was adjusted with finite element method and the distributive laws of stress field and displacement field were obtained. Thus the maximum shear stress was got through the formula of spring intensity. So, two methods on analyzing the stress of cylinder spiral tension spring were introduced in this paper. One is the finite element method; the other is the formula of spring intensity. Then analyzing the spring deformation under load clarifies the function of the finite element method upon spring design, selection and strength check, and improves the reliability of spring design and shortens design time.

A new method for measuring the strength and ductility of thin films

A new method of measuring the mechanical strength of thin films is described. We prepare miniature arrays of four tensile specimens, each 0.25 mm wide, 1 mm long, and 2.2 μm thick, using deposition, patterning, and etching processes common to the semiconductor industry. Each array of four specimens is carried on and protected by a rectangular silicon frame. Thirty-six such specimens are produced on a single wafer. After a specimen frame is mounted, its vertical sides are severed without damaging the specimens. The load is applied by micrometers through a special tension spring. Tensile properties of a 2.2 μm thick Ti–Al–Ti film were determined.