Cross-section distortion and springback characteristics of double-cavity aluminum profile in force controlled stretch-bending

3D elastic-plastic FE model for simulating the force controlled stretch-bending process of double-cavity aluminum profile was established using hybrid explicit−implicit solvent method.Considering the computational accuracy and efficiency,the optimal choices of numerical parameters and algorithms in FE modelling were determined.The formation mechanisms of cross-section distortion and springback were revealed.The effects of pre-stretching,post-stretching,friction,and the addition of internal fillers on forming quality were investigated.The results show that the stress state of profile in stretch-bending is uniaxial with only a circumferential stress.The stress distribution along the length direction of profile is non-uniform and the maximum tensile stress is located at a certain distance away from the center of profile.As aluminum profile is gradually attached to bending die,the distribution characteristic of cross-section distortion along the length direction of profile changes from V-shape to W-shape.After unloading the forming tools,cross-section distortion decreases obviously due to the stress relaxation,with a maximum distortion difference of 13%before and after unloading.As pre-stretching and post-stretching forces increase,cross-section distortion increases gradually,while springback first decreases and then remains unchanged.With increasing friction between bending die and profile,cross-section distortion slightly decreases,while springback increases.Cross-section distortion decreases by 83%with adding PVC fillers into the cavities of profile,while springback increases by 192.2%.

Effect of small tool pin profiles on microstructures and mechanical properties of 6061 aluminum alloy by friction stir welding

The effect of small tool pin profiles on the microstructures and mechanical properties of 6061 aluminum alloy joints using friction stir welding （FSW） technique was investigated. Three different tool pin profiles： threaded tapered cylindrical （T1）, triangular （T2） and square （T3） were used to produce the joints. The results indicate that the weld joints are notably affected by joining with different tool pin profiles. The triangular tool pin profile produces thebest metallurgicaland mechanical weld properties compared with other tool pin profiles. Besides, the lowest tensile strength and microhardness are obtained for the joint friction stir welded with square tool pin profile. It is observed that the smaller tool pin profile and shoulder diameter lead to narrow region of heat affected zone （HAZ） and a desired level of softening. The fracture surface examination shows that the joints are also affected when welding with different types of tool pin profiles. The fracture surface shows that the triangular specimen fails with a ductile fracture mode during the tensile test, while the brittle fracture modes are observed in the joints fabricated with other tool pin profiles （T1 and T3）.

Structure optimization of porthole die based on aluminum profile extrusion process numerical simulation

Porthole die extrusion method is used to produce hollow aluminum profile. Due to the complexity of the porthole die structure and the material flow, it is very difficult to get ideal profile products with the firstly designed die structure. Finite volume numerical simulation was used to analyze the extrusion process of a hollow profile with porthole die and the problem of non-uniform material flow was found. Optimization was made to the originally designed die to solve the problem. Lower load, reasonable seaming location and even extruded forepart with uniform material flow in the optimized die extrusion were obtained. Guidelines to porthole die design were given and it is also concluded that finite volume method with Eulerian description avoids mesh regeneration and is suitable to numerical simulation of severe deformation processes, such as profile extrusion.

Flexible bending of aluminum profiles with polyurethane pad

The high flexibility of profile bending with hyperelastic pad enables it to be a promising method for small lot or single part production, especially for space frame and roof-rail parts in automotive and aerospace industries. Bending of two aluminum profiles with different sections was carried out to investigate the effect of main process parameters on the bending process. Results show that the shape of the cross-section and its relative thickness and section modulus in bending are the main factors that determine the bending properties of the profiles. Roller stroke, properties of polyurethane pad and constraints on profiles are key factors that determine the bending radius and section deformation of bent profiles. Failures and quality problems met in experiments were also analyzed.

Key technologies of "zero die trial" design system for aluminum profile extrusion

Aluminum alloy profile parts are widely used in the fields of aviation,equipmen t,automobile and ornamental industries. The construction method for “zero die trial” intelligent design system of aluminum extrusion die was studied based on KBE idea. An object-oriented knowledge language AEKL(Aluminum Extrusion Knowl edge Language) was developed to construct intelligent knowledge model with three methods,frame,parameters and rules. On the aspect of knowledge reasoning,cas e-based reasoning was employed in addition to traditional rule-based reasoning method. API provided by CAD platform was used in geometry disposal. Finally,th e corresponding prototyping system was established and an design example was sho wn.

Effects of single and multi-stage solid solution treatments on microstructure and properties of as-extruded AA7055 helical profile

The effects of single-stage solution treatment(SST),enhanced solution treatment(EST),high-temperature pre-precipitation(HTPP)and multi-stage solution treatment(MST)on the microstructure,mechanical properties and corrosion resistance of the as-extruded 7055 aluminium alloy(AA7055)helical profile were investigated using differential scanning calorimetry(DSC),optical microscopy(OM),scanning electron microscopy(SEM),electron back-scattered diffraction(EBSD)and transmission electron microscopy(TEM).It was observed that EST and MST could promote the dissolution of the second-phase particles compared with the traditional SST,and the intergranular phases were distinctly discontinuously distributed after HTPP and MST.There was obvious difference in the main texture type and texture strength for the alloy after different solid solution treatments.HTPP could improve the corrosion resistance of the alloy by regulating the intergranular phases,but the mechanical properties were severely weakened.While the good corrosion resistance of the alloy could be obtained by MST without obvious strength loss.As a result,the MST is an ideal solid solution treatment scheme for AA7055.

Study on inhomogeneous cooling behavior of extruded profile with unequal and large thicknesses during quenching using thermo-mechanical coupling model

The interfacial heat transfer coefficient between hot profile surface and cooling water was determined by using inverse heat conduction model combined with end quenching experiment. Then, a Deform-3 D thermo-mechanical coupling model for simulating the on-line water quenching of extruded profile with unequal and large thicknesses was developed. The temperature field, residual stress field and distortion of profile during quenching were investigated systematically. The results show that heat transfer coefficient increases as water flow rate increases. The peak heat transfer coefficient with higher water flow rates appears at lower interface temperatures. The temperature distribution across the cross-section of profile during quenching is severe nonuniform and the maximum temperature difference is 300 ℃ at quenching time of 3.49 s. The temperature difference through the thickness of different parts of profile first increases sharply to a maximum value, and then gradually decreases. The temperature gradient increases obviously with the increase of thickness of parts. After quenching, there exist large residual stresses on the inner side of joints of profile and the two ends of part with thickness of 10 mm. The profile presents a twisting-type distortion across the cross-section under non-uniform cooling and the maximum twisting angle during quenching is 2.78°.

Detection of butt weld of laser-MIG hybrid welding of thin-walled profile for high-speed train

Purpose–This study aims to solve the problem of weld quality inspection,for the aluminum alloy profile welding structure of high-speed train body has complex internal shape and thin plate thickness(2–4 mm),the conventional nondestructive testing method of weld quality is difficult to implement.Design/methodology/approach–In order to solve this problem,the ultrasonic creeping wave detection technology was proposed.The impact of the profile structure on the creeping wave detection was studied by designing profile structural test blocks and artificial simulation defect test blocks.The detection technology was used to test the actual welded test blocks,and compared with the results of X-ray test and destructive test(tensile test)to verify the accuracy of the ultrasonic creeping wave test results.Findings–It is indicated that that X-ray has better effect on the inspection of porosities and incomplete penetration defects.However,due to special detection method and protection,the detection speed is slow,which cannot meet the requirements of field inspection of the welding structure of aluminum alloy thin-walled profile for high-speed train body.It can be used as an auxiliary detection method for a small number of sampling inspection.The ultrasonic creeping wave can be used to detect the incomplete penetration welds with the equivalent of 0.25 mm or more,the results of creeping wave detection correspond well with the actual incomplete penetration defects.Originality/value–The results show that creeping wave detection results correspond well with the actual non-penetration defects and can be used for welding quality inspection of aluminum alloy thin-wall profile composite welding joints.It is recommended to use the echo amplitude of the 10 mm 30.2 mm 30.5 mm notch as the criterion for weld qualification.

铝合金型材挤压弯曲一体化成形技术研究进展

相比于直型材,铝合金弯曲型材更适用于日益复杂的部件形状并能更好地满足轻量化需求,具有提升部件结构强度和刚度、节约空间及增加工业设计自由度等优点,在汽车、高铁和航空航天等领域具有广泛用途。相较于传统冷弯成形技术,挤压弯曲一体化成形技术在生产弯曲型材方面具有流程短、精度高、缺陷少等优点,因而受到广泛关注。重点综述了基于外部弯曲装置和材料差速流动的挤压弯曲一体化成形技术的研究进展,分析并总结了不同挤压弯曲一体化成形技术的原理及发展现状,对比了不同挤压弯曲一体化成形技术的优缺点,最后展望未来发展趋势及其研究方向。

铝型材冷却初拉伸控制

针对铝型材加工过程中的拉伸夹具及冷却时间度量问题,设计适用于不同型号的拉伸夹具,确定了不同加工参数下的最佳冷却时间。通过优化拉伸夹具的设计和冷却时间的控制,能够提高铝型材的加工质量和生产效率。实验结果表明,该方法能够有效地改善铝型材的性能和形状,具有较高的应用价值。

基于改进YOLOv5的铝型材表面缺陷检测算法

针对工业生产中铝合金型材表面缺陷在实际检测中出现漏检和误检的情况,提出一种YOLOv5-Ghost-CBAM-BiFPN模型对铝型材缺陷进行更加精确的检测。首先在YOLOv5 Backbone网中引入了一个轻量级Ghost模块,在保证准确性的前提下显著提高了检测速度。其次,将卷积块注意机制(CBAM)模块添加到Backbone网络的卷积层,以增强特征提取,进一步提高检测精度。此外,考虑到铝型材缺陷尺寸差异,在Neck模块中使用了用于多尺度特征融合的双向特征金字塔网络(Bi-FPN)来聚合不同缺陷类型的特征。实验表明:优化后的模型mAP、精确率P、召回率R都有明显提高。

Simulation of temperature and stress in 6061 aluminum alloy during online quenching process

The cooling curves of 6061 aluminum alloy were acquired through water quenching experiment. The heat transfer coefficient was accurately calculated based on the cooling curves and the law of cooling. The online quenching process of complex cross-section profile was dynamically simulated by the ABAQUS software. The results suggest that the heat transfer coefficient changes during online quenching process. Different parts of the profile have different cooling velocity, and it was verified by water quenching experiment. The maximum residual stress of the profile was predicted using FEM simulation based on ABAQUS software The relations between the temperature and stress were presented by analyzing the data of key points.

2A12T4铝合金型材在苛刻海洋大气环境中的腐蚀规律

采用室内周期性浸泡的模拟试验方法,研究了2A12T4铝合金型材在苛刻海洋大气环境中的腐蚀行为及电化学规律。试验结果表明,在干燥温度为60℃,浸泡在质量分数为3.5%的氯化钠溶液的条件下,随着时间的延长型材出现明显的点蚀现象和较重的层片状剥蚀,腐蚀失重规律符合幂指数规律,腐蚀电位先降低后升高再降低最后趋于稳定。

声学黑洞铝型材板结构减振特性仿真研究

声学黑洞(Acoustic Black Hole,ABH)技术作为一种新型高效的能量聚焦以及振动控制技术,在减振降噪方面具有很好应用潜力。铝型材板结构作为一种夹层结构,具有高比刚度和高比强度等优异轻量化特性,广泛应用于列车外地板、船舶、航空航天等领域中。为了探究ABH和铝型材板结构相结合后是否还具有典型的ABH效应,运用有限元数值模拟方法研究嵌入式ABH铝型材板结构的振动能量聚焦特性。对于频点和频带聚焦特性分析结果表明,在铝型材板结构中嵌入ABH特征结构可以起到显著振动能量聚焦效果。此外,根据聚焦特性分析结果,在ABH铝型材板结构中的ABH特定区域内敷设阻尼材料,并通过仿真计算验证了其减振特性。结果表明,由ABH铝型材板结构附加阻尼材料所得的组合结构振动水平显著低于普通铝型材板结构,部分频率下振动衰减高达52.6 dB。这为轨道交通领域提供了一种很有应用潜力的结构减振降噪新思路。

6005A铝合金空心型材压弯工艺成形特性研究

采用有限元数值模拟技术,对6005A铝合金空心型材压弯过程进行系统研究,定量研究了型材壁厚、模具辊轮直径、辊轮间距和型材高宽比对型材压弯成形质量的影响。采用中心复合法进行了试验设计,并通过灵敏度分析得到了各工艺参数对型材压弯回弹的影响程度的大小。结果表明,在所选取的工艺参数中,型材壁厚对成形最大减薄率、最小减薄率和截面畸变的影响最大;型材高宽比对型材回弹影响最大。采用二阶响应面建立了各变量与各成形性能之间的定量关系。研究结果可为铝合金空心型材压弯成形质量的控制提供参考。

可拆卸金属框架式厨柜系统设计

随着经济的快速增长、生活品质的提高和居住环境的改善,集烹饪、洗涤、储藏为一体的整体厨柜家具日益受到关注。相比传统的板式结构,金属框架结构灵活轻便,可将家具设计成安装简易、可相互拼接、自由组合的形式,以增强厨柜产品对于厨房空间的适应性。采用文献研究法梳理模块化设计原则并通过调研分析法归纳现行金属铝型材框架接合、与横纵向板材接合方式,梳理其在外观、结构等方面的优缺点,为金属框架模块化的设计提供实现依据。最后输出以金属铝型材为支撑框架,木制板材为嵌入板材的可拆卸插接式厨柜设计方案,通过后装式零部件实现厨柜损坏部件局部更换,进而延长整体厨柜产品的使用寿命,同时提高厨柜的模块化程度,适应不同厨房设备安装和用户使用需求,为厨柜的大规模生产定制提供参考。

铝合金榫卯结构的几何特征

铝合金材料是一种优秀的轻量化材料,但由于其焊接性能差,限制了其在汽车上的大量应用。文中提出一种新的铝合金型材连接方案,即铝合金榫卯连接结构,并对其几何特点进行了研究:给出了铝合金榫卯结构的构成,即榫头、卯孔和固定结构;分析了铝合金榫卯结构的几何缺陷;定义了7组描述铝合金榫卯结构特点的基本参数;研究了铝合金型材截面轮廓及其内部结构的拓扑规律;归纳了工程中4类实用的铝合金榫卯结构类型。

喷粉铝合金建筑型材耐老化性能紫外灯快速检测方法的研究

为了获得适合工厂对粉末喷涂铝型材耐老化性能进行质量控制的快速检测方法,研究了紫外灯加速老化试验结果与1 000 h氙灯老化试验结果之间的关系,试验样品为含有不同耐候等级的粉末涂料制成的粉末喷涂铝板,分别测试了组合紫外灯加速老化试验与1 000 h氙灯老化试验的光泽及颜色变化,两种试验结果之间的相关系数为0.85~0.89,216 h的组合紫外灯人工加速老化试验可以近似准确模拟1 000 h氙灯老化试验结果,该试验方法可以作为工厂内部质量控制方法使用。

基于S7-1200 PLC的铝型材切割机控制系统设计

开发设计完成了铝型材门窗切割生产线的PLC控制系统,所开发设计的控制系统实现了铝材锯切的自动化生产,实现了自动上料、精确定位、锯切、自动下料等功能。通过人机交互界面实现生产过程手动操作、运行过程监控、故障报警、数据查询等功能。设计的PLC控制系统具有操作方便、界面简洁、可靠性高等特点,具有很高的市场推广应用价值。