木材弹性模量无损检测方法及其研究现状

弹性模量是木材重要的力学性能指标之一,与其他力学性能之间有较为密切的相关性。如何快速无损检测木材的弹性模量,为其他力学指标的判定提供参考,一直是相关科研人员的研究方向;同时对当前一些检测木材弹性模量的方法及其研究现状进行了归纳总结。     

TMJ-A人造板弹性模量无损检测显示机的误差因素分析

人造板无损检测是在线检测结构用人造板力学性能、保证产品质量的重要环节。本文介绍了弹性模量无损检测设备的功能和工作原理 ,从测试方法、机械系统、控制系统几个方面入手 ,分析了测试误差的形成原因及影响因素 ,为进一步提高人造板无损检测设备的测试精度和可靠性提供依据     

TMJ—1人造板弹性模量无损检测显示机的误差因素分析

人造板无损检测是在线检测结构用人造板力学性能、保证产品质量的重要环节。本文介绍了弹性模量无损检测设备的功能和工作原理，从测试方法、机械系统、控制系统几个方面入手，分析了测试误差的形成原因及影响因素，为进一步提高人造板无损检测设备的测试精度和可靠性提供依据。     

板材弹性模量数控检测设备研究的发展

在论述目前国内外板材弹性模量检测设备研究现状的基础上，提出了目前板材弹性模量检测设备的发展方向，弹性模量检测技术将向应用于生产实际、节约原材料、保证产品安全可靠、实现质量自动控制、提高劳动生产率等全自动化的方向发展。通过与传统的检测方式对比，指出板材弹性模量检测设备应向NDT(无损检测)方向发展，将数控技术与弹性模量检测设备相结合，实现高质量、自动化和节约成本。提出的在线检测板材弹性模量数控检测设备将满足人造板和板材检测的市场需求。     

室外人造板重要性能及其检测方法研究现状

简述了我国室外人造板产品发展概况及重要性能检测,从区域、性能检测和人造板种类三个方面比较分析了国内外对室外人造板重要性能的相关检测标准,阐述了我国现有室外人造板标准存在的不足,提出应尽快制定适合我国室外人造板产品的较为系统的检测方法标准体系。     

两种无损检测方法对CCA处理材的性能评价比较

采用应力波和超声波无损检测,对CCA处理前后沙棘木材密度、应力波和超声波传播速度及动弹性模量的性能进行评价比较.通过配对t检验的数据分析,结果表明:CCA处理对沙棘木材密度有显著影响,但对应力波和超声波传播速度以及动弹性模量的影响不显著;两种无损检测方法所得的数据具有高度的一致性,证明了测定结果的可靠性.     

机械应力式人造板质量在线无损检测技术的研发和应用

静弯曲弹性模量(MOE)是结构用板材(如大片刨花板、定向刨花板、结构胶合板、单板层积材等)最为重要的力学指标,而静弯曲强度(MOR)则是几乎所有人造板(如胶合板、刨花板、中密度纤维板等)的最为重要的力学指标.     

基于单片机的板材在线动态称重系统的设计

目前国内人造板行业发展迅速,但是人造板特别是单板层积材,不管在其生产设备还是质量控制和检测方面都还需要进一步完善和改进。板材密度是检测板材强度的重要指标之一,对板材的机械、物理性能影响很大。通过对在板材的重量(质量)的在线检测,结合几何     

人造板VOCs检测方法与限量规定

VOCs为熔点低于室温而沸点在50～ 260℃的挥发性有机化合物的总称.本文介绍了人造板VOCs对人体及环境的危害,人造板VOCs的来源主要是胶粘剂、表面加工过程、染色过程以及木材本身含有,并综述了国内外人造板VOCs的检测方法和限量规定.     

负离子人造板研究现状及发展建议

负离子人造板通常是将负离子材料与人造板通过浸渍、涂布、共混等方法制成能够持续释放负离子的人造板。文章简述了负离子材料研究现状、负离人造板研究现状、负离子人造板工艺、检测方法和相关标准,指出了负离子人造板存在负离子材料放射性检测监管盲区、负离子人造板可持续释放性能差、负离子人造板质量参差不齐、缺乏关于负离子人造板的抗菌、降醛性能的质量评价标准等问题,并对其发展趋势做出了加强对负离子材料结构的研究、加快开发能释放负离子的新材料并制定负离子材料放射性相关检测标准、加快制定负离子人造板对空气净化作用的评价方法,强化市场监管的发展建议。     

人造板板坯预热及热压工艺研究

综述了人造板预热与热压方面的研究现状,分析了人造板尤其是刨花板预热方面研究的不足。阐述了人造板预热的三个主要研究方向:板坯预热过程中的温度场分布、影响板坯温度场变化的因素及其影响规律以及预热对人造板主要力学性能的影响。     

Effects of material constants and geometry on hygrobuckling of wood-based panels

To understand and predict hygrobuckling behavior of orthotropic or isotropic wood-based composite panels, the closed form equations were derived using both the displacement function with a double sine series and the energy method under biaxial compressions with an all-clamped-edge condition. The critical moisture content depended on Poisson's ratio () and was inversely proportional to 1+ for isotropic panels. It did not depend on the modulus of elasticity (MOE) at all for isotropic panels, but it did depend on MOE ratios for orthotropic panels. As expected, the critical moisture content of plywood was twice as large as the that of hardboard owing to the difference in linear expansions between the two panels. The application of optimum thickness and aspect ratios obtained by the derived equations could improve hygrobuckling resistance without other chemical treatments that could reduce the linear expansion of wood-based panels. This study also indicated that it would be better to increase the aspect ratio rather than the thickness ratio (a/h) from the view-point economics.     

The evaluation of long-term mechanical properties of wood-based panels by indoor exposure tests

Wood-based panels such as plywood, oriented strand board, particleboard, and medium-density fiberboard are used for roof, wall and floor sheathing materials in residential construction. However, the service life of these panels is still unknown due to the lack of long-term durability data. In this paper, test results from six different indoor exposure experiments were integrated to investigate the long-term durability of wood-based panels. The indoor exposure tests lasted for a maximum of 10 years, providing the panels with the changes in moisture content that ranged between 5 and 18%. The reduction in mechanical properties was determined to be in the range of 0–16% for the bending strength, 3–22% for the modulus of elasticity, 11–31% for the internal bond strength and 0–8% for the nail-head pull-through strength. No reduction was recognized for the lateral nail resistance. Furthermore, the concept of deterioration intensity (DI) based on the moisture content history was introduced to predict the long-term durability of the panels, and various calculation methods for DI were discussed so as to increase the correlativity of this property with the reduction in a mechanical property.     

我国室外人造板标准体系的构建

总结我国主要室外人造板产品的种类、产量及分布情况,汇总我国室外人造板相关标准,并与室外人造板标准进行对比分析,指出我国现有标准设置的问题,提出我国应构建包括产品标准和性能检测方法的室外人造板独立标准体系,以促进我国室外人造板的健康快速发展。     

甲醛清除触媒在清除人造板中游离甲醛的试验研究

清除人造板中甲醛的后处理试验结果表明,喷涂甲醛清除触媒后的人造板物理力学性能没有明显变化,甲醛清除触媒对不同种类人造板释放出的甲醛清除效果相同,E3级胶合板喷涂甲醛清除触媒后的甲醛释放量小于（等于）0.12mg/L,清除率大于99．08％。     

不同温湿度条件对人造板理化性能的影响

以强化木地板、中密度纤维板、高密度纤维板、浸渍胶膜纸饰面人造板等5类人造板为试材,研究标准、模拟夏季、模拟冬季等不同温湿度平衡处理条件对上述人造板内结合强度、吸水厚度膨胀率和表面结合强度值等理化性能检测指标结果的影响。结果表明,高温高湿平衡处理使人造板的力学强度增加,吸水厚度膨胀率降低;低温低湿平衡处理使人造板力学强度降低,吸水厚度膨胀率增加;不同平衡处理条件下强化木地板吸水厚度膨胀率差异较大;对饰面板表面结合强度的影响大于素板。     

Determination of melamine content in amino resins by near-infrared spectroscopy

Melamine-urea-formaldehyde resin production has increased in the last years due to low formaldehyde emissions and improved moisture resistance when applied on wood-based panels. Melamine is a relatively high-cost raw material in the resin formulation and has a significant effect on wood-based panel properties. It is important for industry to implement efficient quality control methods to determine melamine content in resins. The main objective of this work was to develop chemometric techniques for off-line monitoring of melamine content using near-infrared spectroscopy. The use of interval partial least squares regression allowed identifying the most interesting spectral ranges for analysis (4,400–4,800 and 5,200–5,600 cm^?1) and the best preprocessing methods to use in the determination of this property. When the appropriate spectral range and preprocessing methods are selected, it is possible to obtain calibration models with high correlation coefficients.     

1 m3 气候箱法测定人造板甲醛释放量的检出限 及不确定度研究

1m3 气候箱法是人造板甲醛释放量测定的主要方法之一。为探究检测过程中的误差来源,提高测量结果的准 确度,从1m3 气候箱法检出限及不确定度等方面进行研究。结果表明：50 mm 光程比色皿的检出限较低,适宜后续 甲醛释放量测试时采用;对于低甲醛释放量的人造板样品,重复测量引入的不确定度对总体不确定度的贡献最大。