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Vehicle structure and aerodynamics
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
A subframe is a rigid, detachable assembly that is connected to the lower body structure through rubber isolation mounts. At the front end of the body it supports an independent suspension system, steering mechanism and the power unit. Acknowledging the latter function it is sometimes referred to as an ‘engine cradle’. Since the suspension system and power unit are themselves connected to the subframe through isolation bushings and mounts, it will be evident that there is a double filtering effect against the transmission of vibration and noise to the car body interior. Another requirement to be met by the front subframe in modern practice is that it must safely redistribute the forces of impact in the event of a head-on collision. A four-point mounting is a typical arrangement for the front subframe. At the rear end of the body a subframe supports an independent suspension system, either wholly or partly according to its layout, and the final drive unit. Similar to the application of a front subframe, the suspension system and final drive unit are likewise connected to the rear subframe through isolation bushings and mounts. It necessarily follows that front and rear subframes, which are pre-assembled with the units they support, readily lend themselves to high volume production methods.
Friction Stir Welding Process
Published in Noor Zaman Khan, Arshad Noor Siddiquee, Zahid A. Khan, Friction Stir Welding, 2017
Noor Zaman Khan, Arshad Noor Siddiquee, Zahid A. Khan
Honda Motor Corporation has implemented FSW for joining aluminum alloy and steel in front structural component of Honda Accord production. The front subframe that carries some suspension components and the engine is made of press formed steel halves and die cast aluminum. FSW was applied at various locations to weld the lap configuration of aluminum to the steel. As claimed by Honda, 25% reduction in the total body weight was achieved compared to previous conventional steel subframe along with 50% reduction in electrical consumption (Honda, 2012).
Force Elements
Published in Georg Rill, Abel Arrieta Castro, Road Vehicle Dynamics, 2020
Georg Rill, Abel Arrieta Castro
Bump and rebound stops limit the suspension travel. The compliance of the topmount avoids the transfer of large shock forces to the chassis. The subframe mounts isolate the suspension system from the chassis and allow elasto-kinematic steering effects of the whole axle.
Bio-Inspired Scheduling for Factory Automation in the TD-LTE System
Published in IETE Technical Review, 2022
Won Jae Ryu, Gandeva Bayu Satrya, Soo Young Shin
Initialization is the process of creating a population of chromosomes. A chromosome comprises genes that are arranged in the order of the frame configuration shown in Table 1. Each gene in the chromosomes is decided randomly but should be decided whether it is uplink or downlink among the released nodes and the transmission state. For example, if the decided frame structure is Index 1, the released nodes in the downlink state should be allocated and decided randomly for the first subframe, which is the downlink. In case of uplink subframes, the released nodes in the uplink state are chosen randomly. However, in an SS subframe, no nodes are allocated. Therefore, according to the state of the subframes in the frame structure, chromosomes are created. In Figure 4, a chromosome created by initialization is shown. In the first subframe, Node 1 is allocated as a downlink transmission. Each node is allocated to the subframes. After the chromosomes are created, each chromosome is evaluated using the fitness function. After the evaluation, a chromosome with the worst fitness score in the first generation is replaced with the scheduling result of DMS.
Diffraction loss model at 0.3–6 GHz for 5G cellular system in microcell urban areas
Published in Electromagnetics, 2019
On the other hand, 5G will have a unified design for all spectrum types/bands and addressing a wide range of use cases and deployment scenarios. Moreover, a new design of time division duplex/frequency division duplex (TDD/FDD) significantly decreases latency by using self-contained subframe, scalable transmission time interval (TTI) and advanced hybrid automatic repeat request (HARQ) in these systems. Furthermore, mobilizing mm waves in 5G will facilitate the use of the vast available amount of higher-band spectrum to deliver extreme broadband services (Qualcomm Technologies, Inc 2016 and Rappaport et al. 2013). In this way, there are two obstacles: high path loss and susceptibility to blockage. High power transmitters and massive MIMO can resolve these problems, respectively (Kristem et al. 2017).
A study on localized expansion defects in tube hydroforming
Published in Journal of the Chinese Institute of Engineers, 2018
Sin-Liang Lin, Zih-Wei Chen, Fuh-Kuo Chen
The forming process for manufacturing the trailing arm of the front subframe involves bending, preforming, and hydroforming. Finite-element models for simulating these three forming processes were constructed. A four-node shell element was adopted to generate the finite-element mesh for the tube, and dies used to manufacture this trailing arm were considered rigid bodies. Convergence tests were conducted to determine a suitable mesh size for the finite-element simulations. To realize accurate simulations, this study used the actual mandrel shape and position to approximate the forming mechanism in the actual tube bending process. The mandrel is located 20 mm from the starting point. The pressure and feed parameters in the simulations were the same as those in the actual production.