纸盒模切版钻孔路径的优化

为提高纸盒模切版数控钻孔的加工效率,以TSP问题作为数学模型,采用较新的蚂蚁算法解决了模切版钻孔路径的优化问题,并获得了满意的结果.     

纸盒模切板 CAM 系统的研究与开发

介绍了纸盒模切板的制造工艺及激光切割技术的特点,详细说明了用VC＋＋开发纸盒模块板CAM系统软件的方法及其功能。     

切槽加工走刀路径优化问题的处理

为提高加工纸盒模切版的效率，运用运筹学、图论学知识，给出奇偶点图上作业法和最小权对集法，解决了走刀路径的优化问题。     

折叠纸盒CAM技术的发展

在分析折叠纸盒加工技术的基础上，重点介绍模切版CAM技术、折叠纸盒CAM系统以及激光直接制作折叠纸盒的技术特点。应用CAM技术不仅能提高效率、有效地保证模切版和背衬版的制作精度以及刀具成型精,这能直接制作高精度的折叠纸盒。     

折叠纸盒模切版在设计时应注意的工艺问题

随着市场经济的发展,折叠纸盒越来越多地应用在商品包装领域,纸盒产品的设计也越来越突出其品位与品质.文中重点讨论了在设计折叠纸盒模切版时,应该考虑纸板厚度、纸纹方向、压痕线宽度、让刀位及糊盒等后工序对模切质量的影响,以便提高折叠纸盒的质量.     

纸盒模切板CAM系统中自动锯槽机的机械设计

自动锯槽机是纸盒模切板CAM系统的重要设备,为了保证加工精度和降低设备成本,故采用机械锯槽工艺和CNC技术相结合的方案,本文着重介绍了整机的结构和数控工作台的设计要点.     

CAD／CAM技术在纸盒行业中的应用

本介绍了纸盒模切板的作用,制造工艺,详细说明了用VC＋＋开发的纸盒模切板CAM系统软件的功能。     

纸盒模切计算机辅助优化排样算法的研究

基于二维图形变换原理提出了一种有效的纸盒模块排样算法，配合一定的人机交互调整，可实现包装纸盒模切版的计算机辅助排样。     

纸盒模切版留桥软件设计

介绍了纸盒模切版留桥设计的必要性,阐述了用图论中的相关理论建立数学模型及实现模切版留桥自动设计软件的开发方法.     

纸盒模切板设计的几个问题

分析讨论了对纸盒模切板设计的影响因素，如纸板纹向、盒坯外形、搭桥、模切工艺等；分析了通过拼接提高原材料利用率的方法，给出了几种愤况的数学公式。     

Bridging crack model for fracture of spruce

An analysis is presented of how cracking in wood can be predicted using fracture mechanics. In situ, real-time, scanning electron microscopy was used as a tool to estimate the physical mechanism of fracture in softwoods using end-tapered double cantilever beam specimens. It was found that bridging behind the crack tip is the main toughening mechanism, which contributes to non-linear wood behavior in the presence of stress concentrations. A new bridging crack model is presented that mimics the observed cracking mechanism. Intrinsic flaw size is found to correspond to the fiber length of spruce.     

Bridging micromechanisms of Z-pin in mixed mode delamination

A numerical model for analyzing the bridging mechanisms of Z-pining in composite laminates is presented. Main failure modes of the Z-pin are: debonding between the Z-pin and matrix, split and rupture of the Z-pin material; these have been taken into account here. The cohesive zone model was utilized to simulate splitting and rupturing within the Z-pin. The interfacial contact between the Z-pin and matrix was assumed to be initially bonded, followed by debonding and frictional sliding. The present model is validated by mode I experiments; the mode II simulation is verified by similar Z-pin shear tests. It is observed that the shear bridging force component increases with the mode II ratio, while the mode I bridging response decreases slightly with the mode II ratio. An enhanced frictional zone is located near the delamination surface. The mode II bridging force in cross-ply laminates is higher than that in UD laminates, while the Z-pin is more likely to rupture in cross-ply laminates when the mode II ratio is relatively high. The presented model can be used to evaluate the Z-pin bridging response. The calculated bridging force is suitable for analyzing the mechanical performance of Z-pinned structures.     

Drilling of composite structures

Structural parts made of composites have frequently to be drilled in the aircraft industry. However, little is know about the interacting conditions between the drilling tool and the material, which may be multi-type and multi-size. This study proposes a model which links the axial penetration of the drill bit to the conditions of delamination (crack opening mode I) of the last few plies. Several types of tool/material contact conditions were analyzed and were compared with experimental measurements, and with a model taken from the literature. Our study shows a close correlation between experiment and calculation when the thrust force of the drill is modeled by taking into account the geometrical nature of the contact between the tool and a laminate composite material.     

韧性颗粒增韧脆性材料的桥接变形计算模型

在脆性材料中弥散加入韧性颗粒可显著提高基体材料的断裂韧性。为了计算材料断裂韧性的增量，本文提出了新的基体与颗粒界面颈缩剥离变形假设，建立了应力与位移之间的关系式。文中还给出了精确的简化计算式。     

Stability of Solder Bridging for Area Array Type Packaging

As ultra-fine-pitch technologies are adopted to enhance the performance of electronic packaging, solder bridging becomes an urgently serious defect. This work presents a computational model using the Surface Evolver program to analyze the stability of solder bridging for area array type packaging. Several factors that affect the stability of solder bridging spanning two identical circular pads are considered herein, including the pad size, the total volume of solder bumps, the pitch between adjacent pads, the contact angle between the molten solder alloy and the pad, the contact angle between the molten solder alloy and the solder mask and the surface tension of the molten solder alloy, respectively. The critical total volume of solder bumps and the critical pitch between adjacent pads are defined as the corresponding critical values to determine the solder bridging from a stable state to an unstable (vanishing) state. The stability of solder bridging spanning three and four identical circular pads is also discussed. Good agreement between the computed critical total volume of solder bumps for solder bridging and that available in the literature exhibits that the model developed in this work can be practically applied to predict the stability of solder bridging.     

Bridging law and toughness characterisation of CSM and SMC composites

This work presents an experimental investigation of the fracture properties of three different short-fiber-reinforced composites [one chopped strand mat (CSM) and two sheet molding compound (SMC) materials]. Fracture tests are performed on double-cantilever beam (DCB) specimens loaded with pure bending moments. In this experimental configuration, the bridging law for the material can be derived directly from measurements. No significant dependency on specimen height was observed in our results. The bridging laws determined can, therefore, be considered as material properties. The coupling between microstructure and fracture behaviour is discussed through the measured bridging laws. The beneficial effect (in terms of fracture energy) of increasing tendency for pull-out is confirmed for one SMC, referred to as Flex-SMC, which shows remarkably high fracture energy, J_c=56.0 kJ/m², compared to a standard SMC, termed Std-SMC, J_c=25.9 kJ/m². This increasing tendency for pull-out is observed to shift the bridging law towards larger crack openings. On the basis of our observations we find the concept of characterising the failure behaviour in terms of bridging laws attractive since it can be used as a tool for the tailoring of the microstructure towards desired fracture behaviour.     

Investigations on Drilling of Bidirectional Cotton Polyester Composite

Cotton fiber composites are currently used in the interior parts of automobiles, insulation boards, fiber boards, and various parts of high-friction mechanical assemblies. These composites are subjected to machining operations. Drilling is an indispensable machining operation for assembly of different parts. The present work aimed to carry out experimental and analytical investigations on drilling of bidirectional cotton polyester composite. Influence of feed, spindle speed, and drill point angle on machining characteristics like thrust force, torque, and delamination factor was studied by conducting experiments derived from Taguchi's L27 orthogonal array. To determine the significance of each drilling process parameters and their interactions, analysis of variance (ANOVA) test was conducted. Modeling of drilling parameters was carried out through multiple regression analysis and their optimization for minimizing cutting forces and machining induced damage was carried out using signal to noise ratio analysis.     

智能控件化虚拟仪器的振动筛动态特性检测

介绍了振动筛动态特性测试的必要性,基于秦氏模型的智能控件化虚拟仪器的概念和原理,将智能控件化虚拟仪器这一全新的概念引入振动筛的动态特性检测过程中。并以振动筛阻尼系数、固有频率和振型为例,介绍了基于智能控件化虚拟仪器技术的钻井振动筛动态特性检测方法。