大规模结构高效静气弹多学科优化设计研究
发布时间：2018-12-15 07:04
【摘要】：现代飞机结构的轻量化需求使得机翼柔度变大,静气弹效应愈加显著。传统工程结构设计优化往往只考虑结构本身的强度刚度性能,并未直接考虑静气弹效应带来的诸如飞机升力效率、副翼效率、焦点位置变化等影响,这使得无法获得满足不同学科需求的最佳结构。随着现代飞机结构更精细化设计以及更深层次挖掘结构潜能的需求,结构设计变量的数量和各学科模型的规模越来越大,结构静气弹多学科优化方法在处理这种大规模优化问题时面临着求解效率低、计算代价大以及导数信息获取困难等挑战,这限制了飞机结构的进一步精细优化设计。本文旨在通过改进亚声速工程面元法求解精度,提高静气弹求解效率以及构造静气弹设计敏度算法等,与大规模结构优化方法结合,力图解决大规模结构静气弹多学科优化面临的技术难点,主要研究工作如下:为着实现机翼弹性气动载荷的高效率与高精度计算,针对高精度计算流体力学(CFD)方法计算耗时过长的矛盾,本文采用工程处理观点,提出了一种改进的亚声速工程面元法—分段精细修正面元法。技术途径为:采用多个迎角下的刚性机翼高精度CFD气动力数据,进行工程面元法的分段修正,获取多段修正因子矩阵;同时,将机翼弹性变形的下洗分段,利用所获取的修正因子矩阵提高机翼弹性气动载荷的计算精度与效率。为进一步提高分段精细修正面元法计算精度,本文提出了一种面元网格划分优化算法,该算法以机翼面元展向和弦向划分数目为优化变量,以静气弹计算中机翼在一较大弹性变形下的高精度CFD气动力数据为基础,在ISGHIT软件平台上对面元网格实现最优划分,使得最优面元网格划分下的修正面元法弹性气动载荷计算结果与高精度CFD结果更为接近。为提高气动与结构耦合界面的数据传递精度与效率,本文采用数值精度高、适应性好的基于径向基函数(RBF)数据传递方法,并对其紧支半径以及传递节点及其数量提出了选择规则,提高了RBF方法的计算效率。工程中的静气弹性能往往采用简单定义,不能完全反映静气弹效应给飞机气动效率及操稳特性带来的影响。本文采用静气弹性能的精确定义并利用复步长求导方法,结合分段精细修正面元法构造了求解升力效率、副翼效率、焦点弦向位置变化率的高效算法,完成了算法程序设计。其中,提出一种双重迭代计算副翼效率的方法,不但能准确求解副翼效率还能计算飞机定常滚转速率,充分反映了机翼弹性和副翼偏角给飞机滚转机动性能带来的影响。为了给予设计者更多的参考信息,本文还提出了弹性升力迎角补偿算法以及弹性滚转速率副翼偏角补偿算法,以求得定载与定速滚转情况下的迎角补偿量与副翼偏角补偿量;同时,设计了机翼发散速度与反效速度的低阶估算算法。基于梯度信息类的优化算法是大规模结构数值优化常用的一种高效算法,为了给予这类优化方法导数信息支持,本文利用所提出的分段精细修正面元法构造了静气弹设计敏度半解析算法,并采取多项措施提高其计算效率。为适应大规模结构静气弹多学科优化程序的模块化组织,本文编写了求解高效、读写规范的静气弹求解程序模块,并通过OPENMP并行技术进一步提高了程序计算效率。通过M6机翼静气弹性能算例考察,并与高精度CFD数据、NASTRAN软件计算结果比较,表明本文提出的多项静气弹性能求解算法以及程序设计具有精度高、效率好的技术优势。最后,综合分析了结构静气弹多学科优化的原理与特点,并利用.MASS文件实现不同工况下不同集中质量加载。文中总结了工程中常用的结构设计约束,阐述了本课题组开发的大规模结构优化程序中的数值优化算法以及约束筛选、变量降维、文件组织、并行处理等核心技术。在该程序基础上,本文完成了静气弹性能约束的并入集成,形成了大规模结构静气弹多学科优化程序。在此工作基础上,本文对一飞翼无人机结构采用699个设计变量,施加4种强度设计工况、2种飞行工况以及近10种约束,进行了结构静气弹多学科数值优化计算,并对优化结果进行了分析校验。结果表明本文采用的大规模结构静气弹多学科优化方法计算高效,并减少结构重量15.66%,优化结果满足工程约束。另外,通过5种不同的约束组合进行结构多学科优化结果比较,分析了各约束对结构重量的影响,以助于发掘结构设计规律。
[Abstract]:The light-weight demand of modern aircraft structure makes the wing soft degree become large, and the static-gas bomb effect is more significant. The optimization of the traditional structural design often only takes into account the strength and rigidity performance of the structure itself, and does not directly take into account the influence of the static-gas effect, such as the lift efficiency of the airplane, the aileron efficiency, the change of the focus position, and the like, which makes it impossible to obtain the best structure to meet the needs of different disciplines. With the more refined design of the modern aircraft structure and the need of the deeper excavation of the structural potential, the number of structural design variables and the scale of each subject model are becoming larger and larger, and the multi-disciplinary optimization method of the structure static gas bomb is faced with low solution efficiency in the process of processing the large-scale optimization problem, The computational cost and the difficulty of obtaining the derivative information have limited the further fine-tuning design of the aircraft structure. The purpose of this paper is to solve the technical difficulties faced by the multi-disciplinary optimization of large-scale structure static-gas bomb by improving the accuracy of the sub-sonic engineering surface element method, improving the solution efficiency of the static-gas bomb and the design of a static-gas bomb, and combining with the large-scale structure optimization method. The main research work is as follows: In order to realize the high efficiency and high precision calculation of the elastic pneumatic load of the wing, the problem that the time consuming is too long is calculated for the high-precision computational fluid dynamics (CFD) method. In this paper, an improved sub-segment fine correction surface element method for subsonic engineering is presented. The technical method comprises the following steps of: adopting high-precision CFD aerodynamic data of a rigid wing at a plurality of angles of attack, performing section correction of the engineering surface element method, acquiring a multi-section correction factor matrix, and simultaneously, and the calculation accuracy and the efficiency of the wing elastic pneumatic load are improved by utilizing the acquired correction factor matrix. in ord to further improve that calculation accuracy of the segment fine correction surface element method, a surface element mesh partition optimization algorithm is proposed, On the basis of the high-precision CFD aerodynamic data of the wing under a large elastic deformation, the optimal division of the meta-grid is realized on the ISGHIT software platform, so that the calculation of the elastic aerodynamic load of the modified plane element method under the optimal plane element mesh is more close to the high-precision CFD result. In order to improve the data transfer precision and efficiency of the coupling interface between the pneumatic and the structure, this paper adopts the radial basis function (RBF) data transmission method with high numerical precision and good adaptability, and puts forward the selection rules for the compact radius and the number of the transmission nodes and the transmission nodes. and the calculation efficiency of the RBF method is improved. The static and static elastic energy in the project often adopts a simple definition, and can not completely reflect the influence of the static-gas elastic effect on the aerodynamic efficiency and the operation stability of the aircraft. In this paper, the precise definition of the static and elastic energy is used and the complex step method is used, and a high-efficiency algorithm for solving the change of the lift efficiency, the aileron efficiency and the position change rate of the focal chord is constructed in combination with the segmented fine correction surface element method, and the algorithm programming is completed. In this paper, a double-iteration method for calculating the aileron efficiency is proposed, which not only can accurately solve the aileron efficiency but also can calculate the steady roll rate of the airplane, and fully reflects the influence of the wing elasticity and the aileron deflection angle to the rolling mobility of the airplane. In order to give the designer more reference information, an elastic lift angle-of-attack compensation algorithm and an elastic roll-rate aileron-off-angle compensation algorithm are presented in this paper to determine the angle-of-attack compensation and the amount of the aileron-off-angle compensation in the case of fixed-load and constant-speed rolling, and at the same time, A low-order estimation algorithm for the speed of divergence and the velocity of the wing is designed. The optimization algorithm based on the gradient information class is a kind of high-efficiency algorithm used in large-scale structure numerical optimization. In order to support the derivative information of this kind of optimization method, this paper constructs a half-resolution algorithm for the design of static-gas bomb by using the proposed segmentation fine correction surface element method. and a plurality of measures are taken to improve the calculation efficiency. In order to adapt to the modular organization of the multi-subject optimization program of large-scale static-gas bomb, this paper has developed a static-gas bomb solution program module for high-efficiency and read-write specifications, and further improves the program calculation efficiency through OPENNMP parallel technology. Through the study of the static and elastic energy of the M6 wing, and compared with the high-precision CFD data and the NASTRAN software, it is shown that the multiple static-gas elastic energy-solving algorithm and the programming have the advantages of high precision and high efficiency. In the end, the principle and characteristics of the multi-disciplinary optimization of the structure static-gas bomb are comprehensively analyzed and used. The mass loading of different concentration under different working conditions is realized by the MASS file. In this paper, the structure design constraints commonly used in the project are summarized, the numerical optimization algorithm in the large-scale structure optimization program developed by the research group, and the core technologies such as constraint selection, variable drop-down, file organization and parallel processing are described. On the basis of this program, this paper completes the integration of the static and gas elastic energy constraints, and forms a large-scale structure static-gas multi-disciplinary optimization program. On the basis of this work, 699 design variables are used in the structure of a flying-wing unmanned aerial vehicle, four strength design conditions, two flight conditions and nearly 10 constraints are applied, and the multi-subject numerical optimization calculation of the structure static-gas bomb is carried out, and the optimization result is analyzed and verified. The results show that the large-scale structure static-gas multi-disciplinary optimization method is efficient and reduces the structural weight by 15.66%, and the optimization results meet the engineering constraints. In addition, the influence of each constraint on the weight of the structure is analyzed through the comparison of five different constraint combinations to the structural multi-subject optimization results, so as to help to find out the law of the structural design.
【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：V279
，
本文编号：2380195
[Abstract]:The light-weight demand of modern aircraft structure makes the wing soft degree become large, and the static-gas bomb effect is more significant. The optimization of the traditional structural design often only takes into account the strength and rigidity performance of the structure itself, and does not directly take into account the influence of the static-gas effect, such as the lift efficiency of the airplane, the aileron efficiency, the change of the focus position, and the like, which makes it impossible to obtain the best structure to meet the needs of different disciplines. With the more refined design of the modern aircraft structure and the need of the deeper excavation of the structural potential, the number of structural design variables and the scale of each subject model are becoming larger and larger, and the multi-disciplinary optimization method of the structure static gas bomb is faced with low solution efficiency in the process of processing the large-scale optimization problem, The computational cost and the difficulty of obtaining the derivative information have limited the further fine-tuning design of the aircraft structure. The purpose of this paper is to solve the technical difficulties faced by the multi-disciplinary optimization of large-scale structure static-gas bomb by improving the accuracy of the sub-sonic engineering surface element method, improving the solution efficiency of the static-gas bomb and the design of a static-gas bomb, and combining with the large-scale structure optimization method. The main research work is as follows: In order to realize the high efficiency and high precision calculation of the elastic pneumatic load of the wing, the problem that the time consuming is too long is calculated for the high-precision computational fluid dynamics (CFD) method. In this paper, an improved sub-segment fine correction surface element method for subsonic engineering is presented. The technical method comprises the following steps of: adopting high-precision CFD aerodynamic data of a rigid wing at a plurality of angles of attack, performing section correction of the engineering surface element method, acquiring a multi-section correction factor matrix, and simultaneously, and the calculation accuracy and the efficiency of the wing elastic pneumatic load are improved by utilizing the acquired correction factor matrix. in ord to further improve that calculation accuracy of the segment fine correction surface element method, a surface element mesh partition optimization algorithm is proposed, On the basis of the high-precision CFD aerodynamic data of the wing under a large elastic deformation, the optimal division of the meta-grid is realized on the ISGHIT software platform, so that the calculation of the elastic aerodynamic load of the modified plane element method under the optimal plane element mesh is more close to the high-precision CFD result. In order to improve the data transfer precision and efficiency of the coupling interface between the pneumatic and the structure, this paper adopts the radial basis function (RBF) data transmission method with high numerical precision and good adaptability, and puts forward the selection rules for the compact radius and the number of the transmission nodes and the transmission nodes. and the calculation efficiency of the RBF method is improved. The static and static elastic energy in the project often adopts a simple definition, and can not completely reflect the influence of the static-gas elastic effect on the aerodynamic efficiency and the operation stability of the aircraft. In this paper, the precise definition of the static and elastic energy is used and the complex step method is used, and a high-efficiency algorithm for solving the change of the lift efficiency, the aileron efficiency and the position change rate of the focal chord is constructed in combination with the segmented fine correction surface element method, and the algorithm programming is completed. In this paper, a double-iteration method for calculating the aileron efficiency is proposed, which not only can accurately solve the aileron efficiency but also can calculate the steady roll rate of the airplane, and fully reflects the influence of the wing elasticity and the aileron deflection angle to the rolling mobility of the airplane. In order to give the designer more reference information, an elastic lift angle-of-attack compensation algorithm and an elastic roll-rate aileron-off-angle compensation algorithm are presented in this paper to determine the angle-of-attack compensation and the amount of the aileron-off-angle compensation in the case of fixed-load and constant-speed rolling, and at the same time, A low-order estimation algorithm for the speed of divergence and the velocity of the wing is designed. The optimization algorithm based on the gradient information class is a kind of high-efficiency algorithm used in large-scale structure numerical optimization. In order to support the derivative information of this kind of optimization method, this paper constructs a half-resolution algorithm for the design of static-gas bomb by using the proposed segmentation fine correction surface element method. and a plurality of measures are taken to improve the calculation efficiency. In order to adapt to the modular organization of the multi-subject optimization program of large-scale static-gas bomb, this paper has developed a static-gas bomb solution program module for high-efficiency and read-write specifications, and further improves the program calculation efficiency through OPENNMP parallel technology. Through the study of the static and elastic energy of the M6 wing, and compared with the high-precision CFD data and the NASTRAN software, it is shown that the multiple static-gas elastic energy-solving algorithm and the programming have the advantages of high precision and high efficiency. In the end, the principle and characteristics of the multi-disciplinary optimization of the structure static-gas bomb are comprehensively analyzed and used. The mass loading of different concentration under different working conditions is realized by the MASS file. In this paper, the structure design constraints commonly used in the project are summarized, the numerical optimization algorithm in the large-scale structure optimization program developed by the research group, and the core technologies such as constraint selection, variable drop-down, file organization and parallel processing are described. On the basis of this program, this paper completes the integration of the static and gas elastic energy constraints, and forms a large-scale structure static-gas multi-disciplinary optimization program. On the basis of this work, 699 design variables are used in the structure of a flying-wing unmanned aerial vehicle, four strength design conditions, two flight conditions and nearly 10 constraints are applied, and the multi-subject numerical optimization calculation of the structure static-gas bomb is carried out, and the optimization result is analyzed and verified. The results show that the large-scale structure static-gas multi-disciplinary optimization method is efficient and reduces the structural weight by 15.66%, and the optimization results meet the engineering constraints. In addition, the influence of each constraint on the weight of the structure is analyzed through the comparison of five different constraint combinations to the structural multi-subject optimization results, so as to help to find out the law of the structural design.
【学位授予单位】：西北工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：V279
，
本文编号：2380195
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