Development of a Side Door Composite Impact Beam for the Automotive Industry

The automobile industry has been searching for vehicles that use less energy and emit fewer pollutants, which has resulted in a high demand for fuel-efficient vehicles. Because of their higher strength-to-weight ratio compared to traditional steel, using fiber-reinforcement composite materials in automobile bodies has emerged as the most effective strategy for improving fuel efficiency while maintaining safety standards. This research paper examined the utilization of fiber-reinforced composite materials in car bodies to meet the increasing consumer demand for fuel-efficient and eco-friendly vehicles. It particularly focused on a carbon-aramid fiber-reinforced composite impact beam for passenger car side door impact protection. Despite the encouraging prospects of the carbon-aramid fiber-reinforced beam, the research uncovered substantial defects in the fabrication process, resulting in diminished load-bearing capacity and energy absorption. As a result, the beam was un-successful in three-point bending tests. This was accomplished by using an I cross-section design with varying thickness because of the higher area moment of inertia. Vacuum-assisted resin transfer molding (VARTM) manufacturing process was used and the finished beam underwent to three-point bending tests.

Dynamic Calculation Method of Beam System Under Low Velocity Impact

The bearing beams and the supporting beams under low velocity impact may be in four different strain stages of deformation depending on the impact intensity and beam structure strength.Based on the different judging conditions of deformation stages,the corresponding calculation models are proposed,the calculation formulae for the determination of the impact force and the beam's lateral displacement are obtained.Calculation shows that the beam's total deflection is small when the flexibility of the supporting component is high and the effect of diminishing deflection disappears almost when the stiffness of the supporting component is high.

Conceptual Design of Natural Fiber Composites as a Side-Door Impact Beam Using Hybrid Approach

This paper presents the conceptual design stage in the product development process of a natural fiber composites of the side-door impact beam,which starts from idea generation to the selection of the best design concept.This paper also demonstrates the use of the integrated Theory of Inventive Problem Solving(Function-Oriented Search)(TRIZ(FOS))and Biomimetics method,as well as the VIseKriterijumska Optimizacija I Kompromisno Resenje(VIKOR)method.The aim of this study was to generate design concepts that were inspired by nature and to select the best design concept for the composite side-door impact beam.Subsequently,eight design concepts were generated using the TRIZ(FOS)-Biomimetics method and finite element analysis were used to analyse their performance and weight criteria using ANSYS software.VIKOR method was used as the multiple criteria decision making tools to compare their performances,weight and cost criteria.As a result,design concepts B-03 and C-02 were ranked as the first and second best,with VIKOR value of 0.0156 and 0.1178,respectively,which satisfied the conditions in VIKOR method.This paper shows that the integrated method of TRIZ(FOS)-Biomimetics and VIKOR can assist researchers and engineers in developing designs that are inspired by nature,as well as in selecting the best design concept using a systematic strategy and justified solutions during the conceptual design stage.

Decision Support Strategy in Selecting Natural Fiber Materials for Automotive Side-Door Impact Beam Composites

The enforcement on sustainable design and environmental-friendly products has attracted the interest of researchers and engineers in the context of replacing metals and synthetic fibers with natural based fibers,especially in the automotive industry.However,studies on sustainable natural fiber material selection in the automotive industry are limited.Evaluation for the side-door impact beam was conducted by gathering product design specification from literature which amounted to seven criteria and it was forwarded to ten decision makers with automotive engineering and product design background for evaluation.The weightage required for decision-making was obtained using the Analytic Hierarchy Process(AHP)method based on six criteria.Following this,the best natural fiber materials to be used as reinforcement in polymer composites were selected using the VIseKriterijumska Optimizacija I Kompromisno Resenje(VIKOR)method.The results using both the AHP and VIKOR method showed that kenaf was the best natural fiber for the side-door impact beam composites.The result showed the lowest VIKOR value,QA1=0.0000,which was determined to be within the acceptable advantage and acceptable stability conditions.It can be concluded that the application of integrated AHP-VIKOR method resulted in a systematic and justified solution towards the decision-making process.

A STUDY ON THE COUNTER-INTUITIVE BEHAVIORS OF PIN-ENDED BEAMS UNDER PROJECTILE IMPACT

The counter-intuitive behaviors of pin-ended beams under the projectile impact axe investigated with ANSYS/LS-DYNA in this paper. It studies in detail their displacement-time history curves, final deformed shapes, energy relationships and projectile impact velocity ranges related to their counter-intuitive behaviors. The influences of the impact positions on their counterintuitive behaviors are also discussed. The results show that no matter where the impact position on the beam is, the counter-intuitive behaviors of pinned beams will occur as long as the impacting velocity lies within a proper range. Corresponding to the occurring of the counter-intuitive behaviors, the rebounding number in the displacement history curves of the beams decreases from a few times to zero with an increase of the impact velocity. The final deformation modes of the beam corresponding to the counter-intuitive behaviors will appear in symmetrical and unsymmetrical forms no matter where the impact position is; the impact velocity of the first-occurring of the counter-intuitive behaviors of the beam increases slowly with the deviation of the impact position away from the mid-span.

Impact coefficient and reliability of mid-span continuous beam bridge under action of extra heavy vehicle with low speed

To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.

梁系结构在低速冲击下的动力计算方法

由于冲击强度和结构强度参数的不同,受力梁和支承梁在低速冲击下可能处于4个不同的应变阶段,根据不同应变阶段的判别条件,提出了相应的计算模型,并推导出了冲击力和梁横向位移的计算公式。通过实例计算表明:当支承构件的柔度很高时,承受冲击梁的总挠度很小;当支承结构的刚度很高时,这个效应在很大程度上消失了。

三跨与单跨护栏系统的抗冲击性能比较

为了解波形梁护栏系统的冲击响应及各跨之间的相互作用对护栏系统变形和受力的影响,设计和实施了半刚性三跨缩比护栏系统冲击试验,各试件尺寸与实际尺寸的缩比比例为1:3.75.对三跨护栏系统与单跨护栏系统的变形、冲击力、速度、能量吸收等特性进行了比较,计算各部件对护栏系统能量吸收的贡献.结果表明:三跨护栏系统吸收了较多的能量,整体的能量吸收更加均匀、合理.试验方法和所得结论为进一步开展工程护栏的优化设计奠定了基础.

Hamilton体系中Timoshenko梁冲击问题的描述和求解

针对T im oshenko梁的冲击问题,在H am ilton体系中通过直接求解H am ilton矩阵的本征值问题并利用共轭辛正交关系,给出了以位移和应力表示的全状态向量解的一般表达式。根据边界条件给出了频率方程和广义模态函数向量。从H am ilton正则方程出发证明了广义模态函数向量的正交性,并给出了动响应及数值结果。从文中可以看出在H am ilton体系中结构弹性动力学问题的描述和求解的一般方法。通过比较本文结果与已有结果可以看出本文方法的正确性和可行性。

Euler梁受横向冲击的解析解

研究了重物对拉压弹性模量不同Euler梁的冲击问题.把被冲击的拉压弹性模量不同Euler梁简化为一集中质量与无重弹簧相连接的单自由度弹性系统,使重物对Euler梁的冲击问题转化为重物对具有集中质量单自由度弹性系统的冲击问题,然后采用动力学方程推导出了重物对梁的冲击力、冲击时间、动载荷系数的函数表达式,克服了能量法仅能给出最大动载荷系数的不足.通过算例分析指出,当拉压弹性模量相差较大时,不能把重物对拉压弹性模量不同Euler梁的冲击问题简单处理为重物对单弹性模量Euler梁的冲击问题,必须考虑拉压弹性模量不同的因素对Euler梁冲击问题的影响.

防撞梁在汽车碰撞中的性能要求及评估方法研究

为了高效评估防撞梁系统变化对整车碰撞性能的影响,基于整车正向开发流程,创新定义了防撞梁系统在整车碰撞中的性能要求,创建了防撞梁系统变化对汽车整车碰撞性能影响的等效评估方法。即从材料参数、材料高速拉伸性能、CAE分析、子系统试验4个方面进行评估和对比,可有效判断防撞梁系统的差异性及对整车碰撞性能的影响。通过研究某平台汽车铝前防撞梁原材料供应商切换对整车碰撞性能的评估案例,验证了等效评估方法的有效性,避免了整车碰撞验证,提升效率,降低费用。

一类悬臂梁双侧碰撞系统的全局动力学研究

考虑悬臂梁双侧碰撞系统,研究其在简谐激励力作用下的全局动力学特性。由于该系统在振动过程中存在屈曲和非光滑间隙2项非线性因素,从而导致其产生丰富的动力学现象。采用数值方法求解其运动微分方程,得到系统在不同参数条件下的相轨线、庞加莱截面图、最大李雅普诺夫指数和分岔图。借助简单胞映射方法,研究了当参数改变时吸引子和吸引域的稳定性及演变规律。最后,通过对分岔图、时间历程图等的研究,发现此系统在一定的参数条件下具有逆倍周期分岔、跳跃、激变、阵发性等复杂的动力学行为。

非对称结构形状记忆合金梁模型的混沌运动

探讨单边约束形状记忆合金梁模型的非对称性以及非光滑因素对于系统混沌运动的影响。通过研究非线性碰撞振动系统共存的光滑Melnikov函数和非光滑Melnikov函数,得到光滑同宿轨分叉和非光滑同宿轨分叉产生Smale马蹄混沌的必要条件。利用相图、Poincare截面图、分岔图和最大Lyapunov指数等数值仿真结果验证混沌阈值条件。结果表明:在一定参数条件下,较大谐和力有利于促进系统同宿轨发生分叉产生混沌;光滑同宿分叉和非光滑同宿分叉的交互作用,可以诱导混沌合并激变的发生。

基于梁-弹簧模型的双级减震系统冲击响应特性

双级减震系统是国内外潜射装置抗冲减震的主要结构形式,明确结构参数对减震性能的影响规律,对工程设计和研究分析具有重要作用。采用3层梁-弹簧模型,从梁结构质量比、双级减震环节刚度比以及梁变形等角度出发,对减震系统中结构变形、结构质量以及减震环节刚度等因素对双级减震系统冲击响应的影响规律进行研究分析。研究结果表明:采用双级减震结构,能够获得有效的抗冲击性能;随着下层相对上层减震环节刚度比的增加,模拟弹体的上层梁最大过载响应减小,而模拟内外筒的中间层与下层梁间最大相对距离增加;随着中层梁相对其他2层的质量比增加,中层梁质量对系统响应的影响减小。

用线性振动比拟法研究不同模量梁的冲击问题

把被冲击的拉压弹性模量不同的梁简化为集中质量与轻质弹簧相连接的单自由度弹性系统,使重物对梁的冲击问题转化为重物对具有集中质量单自由度弹性系统的冲击问题,然后采用动力学方程推导出了重物对梁的冲击时间、动载荷系数的函数表达式,克服了能量法仅能给出最大动载荷系数的不足.通过算例分析指出,有关材料力学教材及专著给出的最大动载荷系数公式,仅是动力学方程推导出的动载荷系数函数式的特例.当拉压弹性模量相差较大时,不能把重物对拉压弹性模量不同梁的冲击问题简单地作为重物对单弹性模量梁的冲击问题处理,必须考虑拉压弹性模量不同的因素对梁冲击的影响.

混合-组合梁斜拉桥支撑体系适用性研究

为研究混合-组合梁斜拉桥结构支撑体系的适用性,以澜沧江大桥为工程背景,建立了漂浮、半漂浮和刚构3种支撑体系的有限元模型,对比分析了不同结构支撑体系下结构的静动力特性。结果表明,半漂浮体系结构的梁端和塔顶位移与刚构体系相差不大,但主梁内力明显小于刚构体系;除塔底弯矩略大于漂浮体系外,半漂浮体系结构的静力学性能均优于漂浮体系;不同支撑体系对结构的动力特性影响较小,三者之间的差异可以忽略不计。综合考虑3种支撑体系对桥梁静动力性能的影响可知,依托工程采用半漂浮体系设计更为合理。

碰撞悬臂梁系统的混沌控制

基于后步控制策略,提出了一种使用分段函数作为控制器的全新混沌控制方法,实现了碰撞悬臂梁系统的混沌控制问题.该方法可以保证将系统的输出在其定义域范围内控制到任意期望的轨道.数值模拟证明了该控制策略的有效性.

基于ELM的H型钢组织预测专家系统

采用极限学习机建立了H型钢组织预测专家系统,可根据H型钢的化学成分、工艺参数及冷却速度来预测轧后钢种的微观组织、晶粒等级和平均冲击功。以某钢厂H型钢的生产数据为专家系统的数据库,批量预测了H型钢的微观组织、平均冲击功和晶粒等级,预测结果表明,决定系数R2较高,拟合程度好;平均绝对百分比误差较小,精度高。为验证专家系统的可行性,采用与预测相同钢材、相同轧制工艺参数的H型钢进行金相实验和夏比冲击实验,由实验得到的微观组织占比、平均冲击功及晶粒等级与预测值基本一致。结果表明:基于ELM建立的H型钢组织预测专家系统,其预测结果精度高,对实际生产有较好的参考价值。

用单自由度系统研究双模量变截面梁的冲击

研究了重物对双模量等高变截面梁的冲击问题.把被冲击的双模量等高变截面梁简化为一集中质量与无重弹簧相连接的单自由度弹性系统,使重物对梁的冲击问题转化为重物对具有集中质量单自由度弹性系统的冲击问题,然后采用动力学方程推导出了重物对梁的动载荷系数、冲击时间的函数表达式,克服了能量法仅能给出最大动载荷系数的不足.通过算例分析,指出有关文献给出的最大动载荷系数公式,仅是动力学方程推导出的动载荷系数函数式的特例.当拉压弹性模量相差较大时,不能把重物对双模量等高变截面梁的冲击问题简单处理为重物对单模量等高变截面梁的冲击问题,必须要考虑拉压弹性模量不同因素对双模量变截面梁受冲击的影响.

摩擦摆支座隔震城轨连续梁桥碰撞响应研究

隔震连续梁桥与邻梁较易发生碰撞并造成损伤,完善的减隔震设计应将碰撞效应考虑在内,以更好地保护梁体。以某城市轨道交通系统三跨连续梁桥为例,建立了该桥及相邻简支梁桥的空间有限元分析模型,采用非线性时程分析方法计算了不同工况中应用摩擦摆支座(FPS)进行减隔震设计后,隔震连续梁桥与相邻简支梁桥梁体的碰撞响应,探讨了梁端间隙、FPS主要设计参数对梁间碰撞响应的影响以及碰撞对隔震连续梁桥地震响应的影响。研究结果表明,同时考虑两端碰撞时,通过增大梁端间隙、减小支座等效滑动半径或增大支座摩擦系数的方式均可有效减少梁端碰撞发生的次数,虽无法保证梁间碰撞力同时减小,但是从效应累积角度考虑,仍然认为是有利于减弱梁间碰撞效应的。其中,增大梁端间隙或支座摩擦系数对碰撞效应的影响规律相似且减弱效果较为明显,减小支座等效滑动半径的效果次之。在设计中可主要通过适当增大摩擦摆支座摩擦系数和梁间间隙的手段来减小梁间碰撞效应。