Dynamic Analysis of Long-Travel, High-Efficiency Shock Absorbers in Freight Cars

1970 ◽  
Vol 92 (3) ◽  
pp. 581-588
Author(s):  
F. Freudenstein
Keyword(s):  
Dynamic Analysis ◽  
High Efficiency ◽  
Sliding Friction ◽  
Classical Mechanics ◽  
Parameter Analysis ◽  
Design Parameters ◽  
Shock Absorbers ◽  
Closure Time ◽  
Lumped Parameter ◽  
Principal Design

A dynamic analysis is presented relating the principal design parameters of a constant force type, dissipative shock absorber to the forces experienced by a resilient lading. The analysis, which correlates the effects of coupler force, lading force, cushion travel, closure time, impact speed, and friction, represents an application of classical mechanics to a dynamical system with sliding friction (Coulomb damping). Although a lumped-parameter analysis forms the basis of the derivation, a procedure is described which takes into account the mass- and compliance distribution within the lading.

System Optimization of Humid Air Turbine Cycle

1994 ◽  
Author(s):  
Yunhan Xiao ◽  
Rumou Lin ◽  
Ruixian Cai
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
System Optimization ◽  
Combined Cycle ◽  
Parameter Analysis ◽  
Specific Power ◽  
Design Parameters ◽  
Humid Air ◽  
Systems Research ◽  
Air Turbine

The humid air turbine (HAT) cycle, proposed by Mori et al. and recently developed by Rao et al. at Flour Daniel, has been identified as a promising way to generate electric power at high efficiency, low cost and simple system relative to combined cycle and steam injection gas turbine cycle. It has aroused considerable interest. Thermodynamic means, such as intercooling, regeneration, heat recovery at low temperature and especially non-isothermal vaporisation by multi-phase and multi-component, are adopted in HAT cycle to reduce the external and internal exergy losses relative to the energy conversion system. In addition to the parameter analysis and the technical aspect of HAT cycle, there is also a strong need for “systems” research to identify the best ways, of configuring HAT cycle to integrate all the thermodynamic advantages more efficiently to achieve high performance. The key units in HAT cycle are analyzed thermodynamically and modelled in this paper. The superstructure containing all potentially highly efficient flowsheeting alternatives is also proposed. The system optimization of the HAT cycle is thus represented by a nonlinear programming problem. The problem is solved automatically by a successive quadratic algorithm to select the optimal configuration and optimal design parameters for the HAT cycle. The results have shown that the configuration of the HAT cycle currently adopted is not optimal for efficiency and/or specific power, and the current pressure ratio are too high to be favorable for highest performance. Based on the current technical practice, the optimal flowsheeting for thermal efficiency can reach 60.33% when TIT=1533K, while the optimal flowsheeting for specific power can achieve 1300kW/kg/s air for TIT at 1533K. The optimal flowsheeting configuration is compared favorably with the other existing ones.

scholarly journals Modeling of a Bio-Thermo-Electric Micro-Cooler

2007 ◽  
Vol 1 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Aparna Prabhakar ◽  
Michael C. Murphy ◽  
Ram V. Devireddy
Keyword(s):  
Optimal Design ◽  
Research Effort ◽  
Fem Analysis ◽  
Element Model ◽  
Parameter Analysis ◽  
Design Parameters ◽  
Thermo Electric ◽  
Thermoelectric Coolers ◽  
Lumped Parameter ◽  
Optimal Distance

This work is a part of an on-going research effort to fabricate a device consisting of an array of micro thermoelectric coolers (μTECs) for highly localized control of temperature in biological systems. A preliminary lumped 1-D parameter model was developed and numerical simulations were carried out to identify the critical and optimal design parameters for a μTEC operating under steady state conditions. The lumped parameter analysis revealed the presence of a new limitation on the maximum possible current through the system, which we denoted as the secondary breakdown current (as opposed to the primary breakdown current associated with Joules heating). To further understand the effect of contact resistances (thermal and electrical), radiative effects, and lateral effects (interactions between μTECs) in our device, we developed a 3-D finite element model (FEM) using ANSYS®. The FEM analysis identified the optimal distance between μTECs to generate discrete and distinct temperatures within the cells located in the extracellular matrix and thus, generating the optimal design specifications for our device.

scholarly journals A Shock Mitigation of Pedestrian-Vehicle Impact Using Active Hood Lift System: Deploying Time Investigation

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Tae-Hoon Lee ◽  
Gun-Ha Yoon ◽  
Seung-Bok Choi
Keyword(s):  
Response Time ◽  
Design Parameters ◽  
Passenger Vehicle ◽  
Governing Equations ◽  
Total Response Time ◽  
Shock Mitigation ◽  
Vehicle Impact ◽  
Driving Speed ◽  
Working Principle ◽  
Principal Design

This paper investigates the deploying time (or response time) of an active hood lift system (AHLS) of a passenger vehicle activated by gunpowder actuator. In this work, this is accomplished by changing principal design parameters of the latch part mechanism of the hood system. After briefly introducing the working principle of the AHLS operated by the gunpowder actuator, the governing equations of the AHLS are formulated for each different deploying motion. Subsequently, using the governing equations, the response time for deploying the hold lift system is determined by changing several geometric distances such as the distance from the rotational center of the pop-up guide to the point of the latch in the axial and vertical directions. Then, a comparison is made of the total response time to completely deploy the hood lift system with the existing conventional AHLS and proposed AHLS. In addition, the workable driving speed of the proposed AHLS is compared with the conventional one by changing the powder volume of the actuator.

scholarly journals Optimal design of high efficiency double helical gear based on dynamics model

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
Fengxia Lu ◽  
Xuechen Cao ◽  
Weiping Liu
Keyword(s):  
Dynamic Model ◽  
High Efficiency ◽  
Bending Strength ◽  
Sliding Friction ◽  
Elastohydrodynamic Lubrication ◽  
Optimization Method ◽  
Transmission Efficiency ◽  
Helical Gear ◽  
Transmission System ◽  
Vibration Displacement

AbstractA 16-degree-of-freedom dynamic model for the load contact analysis of a double helical gear considering sliding friction is established. The dynamic equation is solved by the Runge–Kutta method to obtain the vibration displacement. The method combines the friction coefficient model based on the elastohydrodynamic lubrication theory with the dynamic model, which provides a theoretical basis for the calculation of the power loss of the transmission system. Moreover, the sensitivity analysis of the parameters that affect the transmission efficiency is carried out, and an optimization method of meshing efficiency is proposed without reducing the bending strength of the gears. This method can directly guide the design of the double helical gear transmission system.

Dynamic Analysis of the Pipe Lifting Mechanism on the Deepwater Pipelaying Vessel

2011 ◽  
Vol 199-200 ◽  
pp. 251-256
Author(s):  
Kai An Yu ◽  
Ke Yu Chen
Keyword(s):  
Numerical Analysis ◽  
Dynamic Analysis ◽  
High Efficiency ◽  
Transport Systems ◽  
Kinematic Pair ◽  
Analysis Method ◽  
Numerical Analysis Method ◽  
Upper Limit ◽  
Lifting Capacity ◽  
Limit Position

Based on requirements of pipe transport systems on deepwater pipelaying vessel, a new pipe lifting mechanism was designed. It was composed of crank-rocker and rocker-slider mechanism with good lifting capacity and high efficiency. When the slider went to the upper limit position, the mechanism could approximatively dwell, meeting the requirement for transverse conveyor operation. According to the theory of dynamics, numerical analysis method was used to the dynamic analysis of the mechanism. The results showed the maximum counterforce was at the joint between the rocker and ground, and this calculation could be a guideline for the kinematic pair structure designing.

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