Shock Optimization in a Military Vehicle With Internal Space Frame

2009 ◽  
Author(s):  
Jagadeep Thota ◽  
Mohamed B. Trabia ◽  
Brendan J. O’Toole
Keyword(s):  
Structural Integrity ◽  
Impact Load ◽  
Random Search ◽  
Search Space ◽  
Quadratic Approximation ◽  
Internal Space ◽  
Space Frame ◽  
Military Vehicles ◽  
Space Frames ◽  
Mine Blasts

Space frames are usually used to enhance structural strength of the vehicle while reducing its overall mass. These frames are comprised of beams that are joined together. Recently, space frames are being incorporated in military vehicles. Space frames in military vehicles are however subjected to different types of loading than what is encountered in civilian vehicles such as projectile impacts and land mine blasts. Due to the need to replace a damaged section of the space frame quickly, the proposed space frame is composed of hollow square cross-section bars and angle sections that are bolted together. The space frame is enclosed by uniform-thickness armor, except at the turret. The vehicle is subjected to high impact load to simulate a projectile hit. The objective of this work is to minimize shocks at various critical locations of the space frame while maintaining the overall structural integrity of the vehicle. The vehicle model is parameterized to achieve this objective. This problem is solved using the Successive Heuristic Quadratic Approximation (SHQA) technique, which combines successive quadratic approximation with an adaptive random search within varying search space. The entire optimization process is carried out within MATLAB environment.

Optimization of a Military Vehicle Space Frame Subject to High Impact Loading

2008 ◽  
Author(s):  
Jagadeep Thota ◽  
Mohamed B. Trabia ◽  
Brendan J. O’Toole
Keyword(s):  
Structural Integrity ◽  
Impact Load ◽  
Random Search ◽  
Element Model ◽  
Search Space ◽  
High Impact ◽  
Quadratic Approximation ◽  
Space Frame ◽  
Cross Sectional ◽  
Space Frames

Space frames are usually used to enhance structural strength of the vehicle while reducing its overall weight. These frames are comprised of beams connected together at joints. Recently, space frames are incorporated in military vehicles. However, space frames in this case are subjected to different types of loading than what is encountered in civilian vehicles such as, projectile and land mine attacks. In this paper, a finite element model for the upper half of the space frame of an armored vehicle is developed. The space frame is composed of hollow square cross-section bars and angle sections and is enclosed by uniform-thickness armor, except at the turret. The vehicle is subjected to high impact load that simulates an impact of a projectile. The model is parameterized to minimize the mass of the space frame and vehicle armor by varying the cross-sectional parameters of the beam members and joints, and the thickness of the armor plate, while maintaining the overall structural integrity of the space frame. This problem is solved using the Successive Heuristic Quadratic Approximation (SHQA). This algorithm combines successive quadratic approximation with an adaptive random search within varying search space. The entire optimization process is carried out within MATLAB environment. Results show significant reduction of the mass of the vehicle.

Optimization of the Shock Mitigation Layer in the Space Frame Joints of an Armored Vehicle

2013 ◽  
Author(s):  
Jagadeep Thota ◽  
Mohamed Trabia ◽  
Brendan O’Toole ◽  
Chang-Hyun Lee ◽  
Hong-Lae Park ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Random Search ◽  
Quadratic Approximation ◽  
Frame Structure ◽  
Optimization Process ◽  
Internal Space ◽  
Space Frame ◽  
Beam Elements ◽  
Shock Mitigation ◽  
Armored Vehicle

Armored vehicles have to survive multiple threats such as projectile or land mines. The shocks induced by these threats can harm vehicle occupants or damage sensitive electronic components. Therefore, a goal of modern armored vehicle design is to reduce transmitted shocks to critical components. In this paper, finite element (FE) models of an armored vehicle prototype having the internal space frame structure with the aforementioned features are developed. One model comprises of only solid elements, while another model is created with purely beam elements. The beam elements model is used for optimization studies whose objective is to reduce the shocks within the vehicle, due to mine blast while maintaining its overall structural integrity. The thickness of the rubberized shock mitigation layer at the joints of the space frame is varied during the optimization process. The optimization problem is solved using the Successive Heuristic Quadratic Approximation (SHQA) algorithm, which combines successive quadratic approximation with an adaptive random search while varying the bounds of the search space. The entire optimization process is carried out within the MATLAB environment. The results show that a significant reduction in the shock can be achieved using this approach.

Optimization of the Closure-Weld Region of Cylindrical Containers for Long-Term Corrosion Resistance Using the Successive Heuristic Quadratic Approximation Technique*

2003 ◽  
Vol 125 (3) ◽  
pp. 533-539 ◽  
Author(s):  
Zekai Ceylan ◽  
Mohamed B. Trabia
Keyword(s):  
Finite Element ◽  
Random Search ◽  
Nonlinear Problems ◽  
Search Space ◽  
Induction Coil ◽  
Quadratic Approximation ◽  
Approximation Technique ◽  
General Corrosion ◽  
Highly Nonlinear

Welded cylindrical containers are susceptible to stress corrosion cracking (SCC) in the closure-weld area. An induction coil heating technique may be used to relieve the residual stresses in the closure-weld. This technique involves localized heating of the material by the surrounding coils. The material is then cooled to room temperature by quenching. A two-dimensional axisymmetric finite element model is developed to study the effects of induction coil heating and subsequent quenching. The finite element results are validated through an experimental test. The container design is tuned to maximize the compressive stress from the outer surface to a depth that is equal to the long-term general corrosion rate of the container material multiplied by the desired container lifetime. The problem is subject to several geometrical and stress constraints. Two different solution methods are implemented for this purpose. First, an off-the-shelf optimization software is used. The results however were unsatisfactory because of the highly nonlinear nature of the problem. The paper proposes a novel alternative: the Successive Heuristic Quadratic Approximation (SHQA) technique. This algorithm combines successive quadratic approximation with an adaptive random search within varying search space. SHQA promises to be a suitable search method for computationally intensive, highly nonlinear problems.

Swarm Intelligence for Multi-Objective Optimization in Engineering Design

2018 ◽  
pp. 239-250 ◽  
Author(s):  
Janga Reddy Manne
Keyword(s):  
Swarm Intelligence ◽  
Engineering Design ◽  
Random Search ◽  
Search Space ◽  
Population Based ◽  
Design Problems ◽  
Multi Objective ◽  
Hard Constraints ◽  
Decision Variables ◽  
Engineering Design Problems

Most of the engineering design problems are intrinsically complex and difficult to solve, because of diverse solution search space, complex functions, continuous and discrete nature of decision variables, multiple objectives and hard constraints. Swarm intelligence (SI) algorithms are becoming popular in dealing with these kind of complexities. The SI algorithms being population based random search techniques, use heuristics inspired from nature to enable effective exploration of optimal solutions to complex engineering problems. The SI algorithms derived based on principles of co-operative group intelligence and collective behavior of self-organized systems. This chapter presents key principles of multi-optimization, and swarm optimization for solving multi-objective engineering design problems with illustration through few examples.

Optimization of the Closure-Weld Region of Cylindrical Containers for Long-Term Corrosion Resistance

2001 ◽  
Author(s):  
Zekai Ceylan ◽  
Mohamed B. Trabia
Keyword(s):  
Finite Element ◽  
Random Search ◽  
Element Model ◽  
Stress Constraints ◽  
Induction Coil ◽  
Quadratic Approximation ◽  
General Corrosion ◽  
Highly Nonlinear ◽  
Weld Area

Abstract Welded cylindrical containers usually experience stress corrosion cracking (SCC) in the closure-weld area. Induction coil heating technique may be used to relieve the residual stresses from the closure-weld. This technique involves localized heating of the material by the surrounding coils. The material is then cooled to the room temperature by quenching. A two-dimensional axisymmetric finite element model is developed to study the effects of induction coil heating and subsequent quenching. The finite element results are validated through an experimental test. The parameters of the design are tuned to maximize the compressive stress within a layer of thickness from the outer surface that is equal to the long-term general corrosion of Alloy 22 (Appendix A). The problem is subject to geometrical and stress constraints. Two different solution methods are implemented for this purpose. First, an off-the-shelf optimization software is used to obtain an optimum solution. These results are not satisfactory because of the highly nonlinear nature of the problem. The paper proposes a novel alternative: the Successive Heuristic Quadratic Approximation (SHQA) technique. This algorithm combines successive quadratic approximation with an adaptive random search. Examples and discussion are included.

Wave Impact Load and Corresponding Nonlinear Response of a Semi-Submersible

2019 ◽  
Author(s):  
Yinghao Guo ◽  
Longfei Xiao ◽  
Handi Wei ◽  
Lei Li ◽  
Yanfei Deng
Keyword(s):  
Spatial Distribution ◽  
Structural Integrity ◽  
Impact Load ◽  
Wave Crest ◽  
Impulsive Effect ◽  
Offshore Platforms ◽  
Wave Impact ◽  
Global Response ◽  
Local Wave ◽  
Incident Waves

Abstract Offshore platforms operating in harsh ocean environments often suffer from severe wave impacts which threaten the structural integrity and staffs safety. An experimental study was carried out to investigate the wave impact load and its effect on the global response of a semi-submersible. First, two typical wave impact events occurring successively in the wave test run are analyzed, including the characteristics of incident waves, relative wave elevations and the spatial distribution of the wave impact load. Subsequently, the corresponding global response of the semi-submersible under these two wave impacts are investigated in time domain. It reveals that compared with the incident wave, the relative wave elevation has a more straightforward relationship with the wave impact load. The relative wave crest height is associated with the spatial distribution of the wave impact load, while the local wave steepness matters more in the magnitude of the wave impact load. The impulsive effect of the wave impact load on the motion behaviors is not obvious. But severe wave impacts can introduce excessive horizontal accelerations and nonlinear behaviors like ringing in the acceleration response.

scholarly journals Random search with k -prototypes algorithm for clustering mixed datasets

2011 ◽  
Vol 467 (2132) ◽  
pp. 2387-2403 ◽  
Author(s):  
Duc-Truong Pham ◽  
Maria M. Suarez-Alvarez ◽  
Yuriy I. Prostov
Keyword(s):  
Optimization Algorithm ◽  
Random Search ◽  
Search Space ◽  
Population Based ◽  
The Other ◽  
Bees Algorithm ◽  
Neighbourhood Search ◽  
Promising Solution ◽  
Number Of Iterations ◽  
Selection Of

A new algorithm to cluster datasets with mixed numerical and categorical values is presented. The algorithm, called RANKPRO (random search with k -prototypes algorithm), combines the advantages of a recently introduced population-based optimization algorithm called the bees algorithm (BA) and k -prototypes algorithm. The BA works with elite and good solutions, and continues to look for other possible extrema solutions keeping the number of testing points constant. However, the improvement of promising solutions by the BA may be time-consuming because it is based on random neighbourhood search. On the other hand, an application of the k -prototypes algorithm to a promising solution may be very effective because it improves the solution at each iteration. The RANKPRO algorithm balances two objectives: it explores the search space effectively owing to random selection of new solutions, and improves promising solutions fast owing to employment of the k -prototypes algorithm. The efficiency of the new algorithm is demonstrated by clustering several datasets. It is shown that in the majority of the considered datasets when the average number of iterations that the k -prototypes algorithm needs to converge is over 10, the RANKPRO algorithm is more efficient than the k -prototypes algorithm.

Application of an Improved Genetic Algorithm with the Search Space Compression in TSP

2013 ◽  
Vol 765-767 ◽  
pp. 687-689
Author(s):  
Yi Song ◽  
Ni Ni Wei
Keyword(s):  
Genetic Algorithm ◽  
Traveling Salesman Problem ◽  
Random Search ◽  
Search Space ◽  
Traveling Salesman ◽  
Improved Genetic Algorithm ◽  
Space Compression ◽  
Accelerate Convergence ◽  
The Traveling Salesman Problem ◽  
Exponential Relation

The Traveling Salesman Problem is a combinatorial optimization problem, the problem has been shown to belong to the NPC problem, the possible solution of Traveling Salesman Problem and the scale of the cities have the exponential relation, so the more bigger of the scale. In this paper, improve the search process of the genetic algorithm by introducing the idea is to compress the search space. The simulation results show that for solving the TSP, the algorithm can quickly obtain multiple high-quality solutions. It can reduce the blindness of random search and accelerate convergence of the algorithm.

The Application of Slip Joint Use in Space Frame Structure for Vehicle

2013 ◽  
Vol 423-426 ◽  
pp. 1944-1947
Author(s):  
Sheng Yun Lee ◽  
Ting Hao Cheng ◽  
Yu Ting Lin
Keyword(s):  
Dimensional Accuracy ◽  
Element Model ◽  
Frame Structure ◽  
Poor Control ◽  
Space Frame ◽  
Space Frames ◽  
The Common ◽  
The Finite Element Model ◽  
Joint Method ◽  
Space Frame Structure

The purpose of this paper is to analysis the finite element model of joint methods for chassis space frames of vehicles. Common tee-joint often have poor control of dimensional accuracy. The analysis includes the common tee-joint and new joint method. Although the new joint method will increase in weight a little and easily adjust the accuracy of space frame, it will also improve the connection strength.

The Development of MURJ-3D: A Modular, Universal, Re-Configurable Joint for 3-D Space Frame Applications

1997 ◽  
Vol 12 (2) ◽  
pp. 89-100 ◽  
Author(s):  
N.S. Bardell ◽  
D. Brown ◽  
P.D. Shearn ◽  
D.P. Turner ◽  
J.R. Longbourne ◽  
...  
Keyword(s):  
Space Frame ◽  
Exact Number ◽  
Space Frames ◽  
Lattice Space ◽  
Design Build ◽  
Test Schedule

Currently available joints used for constructing 3-D lattice space-frames effectively prescribe the geometry of the resulting framework and favour regular, repetitive structural geometric forms; to embrace more general geometric forms requires costly, individually-tailored, joints to be made. This paper describes a new, modular, universal, reconfigurable, joint (MURJ-3D) which has been designed specifically to overcome such problems, and hence to permit the construction of both regular and irregular framework geometries with equal facility. Each MURJ-3D acts as a structural node in any general 3-D space-frame by joining together a large number of lattice members whose longitudinal axes all coincide at a point in space. The exact number of lattice members that can be attached to a single MURJ-3D is not specified, but the capacity of the joint is such that the number of available connections is likely to exceed the maximum number of members required in any given application. The location of the connections is, for all practical purposes, infinitely variable over the surface of a sphere. The MURJ-3D is designed to permit subsequent full reconfiguration of the framework member geometry, including the addition and/or removal of individual members; its application to temporary structures, or those requiring in-situ erection, is particularly germane. The concept presented here is validated using a design, build and test schedule, which clearly demonstrates the general efficacy of the joint.

Sign in / Sign up

Export Citation Format

Share Document