摘要：为研究木骨架正交斜放竹条覆面墙板的竖向承载能力,设计了3种覆面组合墙板试件(双面竹条,竹条-石膏板,层板-石膏板),每种墙板试件各3块,尺寸为1200×1200 mm。通过对试件进行竖向承载力试验,研究对比分析3种覆面组合墙板的破坏模式,荷载-变形曲线以及极限承载力。试验结果表明:墙体破坏初期,竹条覆面部分发生弯曲,层板与石膏板中部发生弯曲;继续加载,覆面与龙骨连接铁钉拔出,部分竹条失去与墙体连接,层板石膏板发生弯折破坏;最终,竖向龙骨整体失稳导致墙体破坏。层板-石膏板组合墙板竖向龙骨表现为墙板平面内失稳破坏,覆面为竹条的组合墙板竖向龙骨表现为墙板平面外失稳破坏。分析结果表明:正交斜放竹条覆面可提高试件竖向承载能力,且延性优于层板-石膏板覆面墙板试件。

摘要：Stiffened composite panels are used within many applications, from aerospace to marine applications. Stiffened panels are utilized for their high strength to weight ratio and flexibility of layups while counteracting the low stiffness exhibited by composites. Complications arise when attempting to utilize the full variability of layups in conjunction with reliability constraints creating a complex design problem when constrained by both buckling and material strength. To aid the process of optimizing the design of composite structures and layups, while ensuring a low mass, this paper presents a bi-level optimization scheme for minimization of the weight of tophat stiffened composite panels with probabilistic deflection constraints. To improve the computational efficiency, an energy based grillage method is formulated and applied for the investigation of buckling problems under bi-directional in-plane loads. The method is validated by comparing the results obtained from FE model calculations. The variables that have a large impact on the structural safety have been identified by both safety index and COV based reliability analysis. A parametric study of plate dimensions and loading ratios is conducted to investigate the coupling effects on critical buckling load. The method presented in this paper, makes it possible for engineers to improve their designs, at an early stage, with an integrated consideration between product performance and design parameters.

摘要：为研究冬枣振动采收过程中果实的运动规律和脱落轨迹,采用改装的电动往复锯连接自制振动采摘头对树枝进行高速振动,用高速相机记录不同振动频率(15、20、25 Hz)下冬枣果实的运动轨迹,对高速视频进行分析,计算在振动过程中的枣果脱落类型、脱落时间和运动轨迹,以及果实脱落时的速度、加速度和惯性力。结果表明:1)冬枣果实的主要脱落类型是旋倾型,15、20和25Hz时,旋倾型脱落的果实个数比例分别为81%、66%和78%,参考已有研究经验,冬枣机械收获宜选用连续式振动设备;2)随着振动频率的增大,果实的平均脱落时间减小,3个频率的果实脱落时间分别为1.71、0.54和0.43s,15Hz时果实脱落时间与20和25Hz时的果实脱落时间存在显著性差异,而20与25Hz时的果实脱落时间无显著性差异;3)果实的速度和加速度随着振动频率的增大而增大,但不同频率的果实平均脱落惯性力不存在显著性差异,3个频率下分别为0.48、0.43和0.49N。本研究结果可为机械收获装备的设计选型与研发提供理论依据。

摘要：对纤维加强聚合物(FRP)材料加强钢筋混凝土梁在火灾中的防火性能进行了研究。试验结果显示,防火材料能够帮助构件达到标准防火性能,同时对不断增长的FRP应用也很重要。介绍了不同文献对FRP在高温下的性能所做的研究以及目前标准对建筑构件的耐火极限要求。对两个大型试验进行了介绍。试验材料为混凝土梁构件,外部用FRP板加强,并且三分之二用专利耐火隔热材料保护。给出了试验结果,并重点强调了曝火状态下所测得的构件温度。试验数据验证了热传导数值模型,该模型可用于预测加强并绝缘钢筋混凝土梁构件内的温度。试验结果和模型数据显示,正确设计和进行绝缘保护的FRP加强梁构件耐火极限能够达到4h或者以上。

摘要：通过响应面Box-Behnken实验设计,对玻化微珠增强秸秆灰/水泥复合材料的性能进行了优化研究。研究结果表明,所选模型具有显著性(P<0.05),模型优化得出的复合材料最优工艺参数为:掺入量为10%,粒径为600μm。在最优工艺下,玻化微珠增强秸秆灰/水泥基复合材料的导热系数为0.2919 W/(m·K),相比未优化处理的,导热系数降低了36%。

摘要：计算机辅助设计正算法已被广泛应用于船舶设计领域,而缺少蓝图或必要数据的船需要复原时正算法就不再适用。反算法应用于缺少蓝图或其他资料的船舶的复原,是逆向设计思维的一种应用。该方法利用需复原船舶已有的图纸资料数据,合理假设,再对假设进行验证,从而得出需复原船舶缺失的数据,逆向推得设计者所需要的设计资料。

摘要：Ankylosing spondylitis(AS) is a chronic inflammatory disease that affects 1% of the general population. As one of the most severe types of spondyloarthropathy, AS affects the spinal vertebrae and sacroiliac joints, causing debilitating pain and loss of mobility. The goal of this review is to provide an overview of AS, from the pathophysiological changes that occur as the disease progresses, to genetic factors that are involved with its onset. Considering the high prevalence in the population, and the debilitating life changes that occur as a result of the disease, a strong emphasis is placed on the diagnostic imaging methods that are used to detect this condition, as well as several treatment methods that could improve the health of individuals diagnosed with AS.

摘要：CO_(2)驱最小混相压力(MMP)是衡量能否达到混相驱的重要参数,因此,为提高混相驱的应用率,迫切需要降低CO_(2)与原油间的最小混相压力,而油藏中加入助混剂是降低最小混相压力的有效手段。目前助混剂按照所含元素可分为碳氟、硅氧烷、碳氢(含氧)三大类。为了降低成本,提高助混效果,应在碳氟类助混剂加入碳氢类结构,向混合型的方向发展,而碳氢类助混剂具有良好的助混效果,并且有提升的空间,关键是找到合适的亲CO_(2)结构,计算机模拟是研究微观机理,辅助结构设计的重要手段。相比于碳氟类和硅氧烷类,碳氢类助混剂的成本较低,从成本的角度看最有应用潜力。目前影响助混剂规模化应用的主要因素是成本上的限制,未来推广应用需要石油与化工从业者的密切配合,重点介绍助混剂降低MMP的机理,总结了目前已有助混剂的结构以及助混效果,分析了助混效果的影响因素,展望了助混剂设计的发展方向。