Name: preparation of aligned steel fiber reinforced cementitious composite and its flexural behavior
Uploaded: 2018-06-27T12:30:00.000+00:00
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Description: Watch this Scientific Journal Video about Preparation of Aligned Steel Fiber Reinforced Cementitious Composite and Its Flexural Behavior at JoVE.com

作者感谢中国国家自然科学基金 (51578208 号赠款)、河北省自然科学基金 (批准号:) 的财政支持。E2017202030 和 E2014202178), 河北省大学科技研究重点项目 (批准号:ZD2015028)。

1. 电磁磁场设置
注: 磁场是由一个空心腔的螺线管产生的。该装置是一个聚对苯二甲酸 (PBT) 板螺线管骨架盘绕4-6 层搪瓷绝缘铜线和包装的塑料绝缘层保护 (图 1)。将线圈连接到直流后, 线圈中的电流在螺线管腔内产生一个均匀的电磁场, 具有固定方向和恒定的磁感应强度。使用磁场将钢纤维与新鲜砂浆对齐, 并准备 ASFRC 试样。在这项研究中, 我们准备了150×150×550毫米棱镜标本, 使用的电磁阀室大小的250×250×750毫米。
<ol><li>将磁感应强度与电磁线圈的电流相关。<ol>
<li>将螺线管连接到 DC, 并将电流从0到 10 a 与步骤长度 1 a 测量并记录电磁室中的磁感应强度, 使用特斯拉计。</li>
		<li>绘制磁感应强度-电流曲线 (图 2), 将在以后的步骤中使用, 以确定螺线管的必要电流。 注: 在将螺线管连接到电源和所有其他与电力有关的操作程序时, 小心地遵循电气安全程序。</li>
	</ol>
</li>
</ol>2. 新鲜砂浆的实用性
<ol><li>准备三砂浆与钢纤维体积分数分别0.8%、1.2% 和2.0% 混合 (表 1)。三混合有相同的基质组成与水水泥砂比为 0.42:1: 2。根据混合比, 重0.5 公斤水泥, 1.0 公斤沙子和0.21 公斤水为可加工性测试。</li>
	<li>先把水加入砂浆搅拌机。然后加入水泥。三十年代混合水和水泥。然后再混合三十年代, 在这个三十年代的混合, 逐渐增加了沙子的搅拌机。然后再混合六十年代。</li>
	<li>根据中国建筑砂浆性能试验方法标准 (JGJ/T70-2009)19, 用下沉深度计测试混合料的下沉深度。</li>
	<li>重复步骤2.2 和 2.3, 调整减水剂的用量, 直到下沉深度降到50-100 毫米范围。记录生产所需的可行性的减水剂的用量, 并在表 1中补充它作为混合比例的一部分。还可以在可加工性达到后, 测试新鲜砂浆的特定密度。在上述试验中, 聚羧酸系高效减水剂的最佳用量为 0.10% (与水泥质量比), 新鲜砂浆的比重为2186公斤/米3。</li>
	<li>使用共轴旋转砂浆流变仪测试新鲜砂浆的粘度 (图 3)。流变仪有一个水浴, 可以保持样品容器的温度在20摄氏度。<ol>
<li>将300毫升的新鲜砂浆混合在前5分钟内, 放入样品容器中。</li>
		<li>开始粘度测试。探头逐渐滴入容器中的新鲜砂浆, 容器开始旋转。当新的砂浆在旋转容器内移动时, 它会在探针上应用剪切力。在该过程中, 流变仪记录了剪切应力和剪切速率, 并将剪切应力曲线绘制为剪切速率。曲线的斜率是灰浆的粘度20,21。在本研究中, 新鲜砂浆的粘度为0.82 失礼</li>
	</ol>
</li>
</ol>3. 标本准备
<ol><li>确定磁场的磁感应强度和电磁线圈的电流。<ol>
<li>利用阶梯2.5.2 中确定的水泥砂浆粘度, 计算用方程对钢纤维在水泥砂浆中的磁场感应强度 (1):13 <img alt="Equation 1" src="/files/ftp_upload/56307/56307eq1v2.jpg">(1) 凡B是磁感应强度, η是粘度的新鲜砂浆, lf 是钢纤维的长度, m是单个钢纤维的质量, rf 是钢纤维的半径, μ是钢纤维的渗透性, μ0是真空的透气性, Δt为时间间隔, α(t + Δt) 是下一次间隔时的角加速度。根据试验所用钢纤维的粘度和参数, 所需的磁感应强度为 9.83 mT。</li>
		<li>根据图 2或方程 (2) 确定所需电磁线圈的电流, 以产生足够的磁感应强度:14 <img alt="Equation 2" src="/files/ftp_upload/56307/56307eq2v2.jpg">(2) 在我所要求的电流中, N是电磁线圈的数目, 而L是螺线管的长度。 使用等式 (2), 所需的电流是 8.3 a, 而从图 2它是大约 8.5 a。</li>
	</ol>
</li>
	<li>准备 ASFRC 标本<ol>
<li>使用15升砂浆搅拌机混合新鲜砂浆。对于每批, 根据表 1中列出的混合比例混合7.5 升砂浆。表1表示 ASFRC 混合物为 Vf, 其中 a 表示钢纤维对齐, Vf表示钢纤维的体积分数。因此, 钢纤维混凝土的混合物被表示, 作为比较, r-Vf, 其中 r 表明, 钢材是随机分布。钢纤维混凝土混合物没有列在表 1 , 但有相同的比例 ASFRC。</li>
		<li>根据常规程序, 对原材料进行称量, 混合钢纤维增强水泥砂浆。</li>
		<li>将新鲜的砂浆倒入塑料模中, 150×150×550的尺寸清晰. 混合后迅速浇铸试样, 避免失去可加工性。从水泥和水的接触中铸造一 ASFRC 棱镜需要大约25分钟。</li>
		<li>将模具移动到压实表上, 然后在压缩工作台上打开三十年代. 根据需要添加更多砂浆, 以确保模具完全填充。</li>
		<li>把模具放进螺线管的腔内。</li>
		<li>开关在五十年代的电磁线圈和压实表。 注: 对于普通混凝土, 合理的压实时间约为60-120 秒。在此测试中, 尝试控制此范围内的总压缩时间。较长的压实时间可改善钢纤维的对准;然而, 它可能导致过度压实和因此离析 (如果有的话, 钢纤维和粗骨料的下沉)。压缩时间越小, 钢纤维和疏松混凝土的线形就越差。</li>
		<li>关掉压实表。</li>
		<li>在压实表完全停止后, 关掉电磁线圈。</li>
		<li>轻轻地从螺线管中取出模具, 用铲子将砂浆的顶面光滑。避免干扰顶部表面附近的钢纤维。</li>
	</ol>
</li>
	<li>对于每个混合, 准备三电磁处理标本 (以下步骤 3.2. 2-3. 2.9) 和三非电磁处理标本 (以下步骤 3.2. 2-3 和 3.2.9)。在非电磁处理标本的制备中, 总压实时间为八十年代--与制备电磁处理试样时相同。</li>
	<li>将标本留在室内, 并在其模具中24小时。然后脱模和治疗雾室中的标本, 直到它们被用于机械测试。</li>
</ol>4. 三点弯曲试验
<ol><li>28天后, 取出固化室中的标本, 并标记装货位置 (A)、支撑 (B)、中跨偏转 (C) 和 LVDT 固定点 (图 4)。</li>
	<li>将试样放在 MTS 测试机的三点弯曲试验台 (图 4) 上, 并用试样的每一侧表面的 LVDT 保持架固定 LVDT 到中跨 (图 4)。</li>
	<li>将 LVDT 连接到数据记录。然后设置测试机控制 PC 上的数据采集频率。</li>
	<li>通过提高底部支撑来逐步提高试样的承载力, 使试验机上部加载单元非常接近, 但不接触试样的顶端表面。</li>
	<li>零初始负载、中跨偏转 (LVDT) 和位移 (加载单元) 值。</li>
	<li>开始测试并将三点弯曲载荷应用于具有位移控制的试样, 其速度为0.2 毫米/分钟. 记录试样的荷载和中跨挠度的完整历史。</li>
	<li>观察试样的载荷和变形。峰值后, 当位移大于30毫米时, 停止测试。通常, 试样开裂, 载荷小于 1.0 kN。</li>
	<li>重复步骤 4.1-4.7 测试所有标本。</li>
</ol>5. 钢纤维取向分析
<ol><li>计算断裂截面上钢纤维的数量。<ol>
<li>把标本分成两部分在破裂的部分。</li>
		<li>测量和记录钢纤维在水泥砂浆试样断裂断面上的定位。方向是钢纤维和试样轴线之间的夹角。由于手工测量钢纤维的方向是困难的, 可能产生不准确的测量, 方向可以归类为六个角度范围: 0-15 °, 15-30 °, 30-45 °, 45-60 °, 60-75 °和 75-90 °。记录每组钢纤维的数量, 然后用方程计算试样的平均纤维取向效率系数 (3): <img alt="Equation 3" src="/files/ftp_upload/56307/56307eq3v2.jpg">(3) ηθ 是钢纤维的平均取向效率系数, lf 是单个钢纤维的长度, n是裂纹截面上钢纤维的总数量, 而θi 是钢纤维与磁场方向的夹角 (在计算中, 每个组的钢纤维采用角度范围的中间值)。</li>
	</ol>
</li>
	<li>执行 X 射线计算机断层扫描分析。<ol>
<li>从每个迫击炮标本中剪下一个75毫米的立方体。</li>
		<li>使用 x 射线计算机层析成像系统对立方体进行 x 射线扫描。将标本放在测试平台上, 开始扫描。试样逐渐旋转360°, 机器记录每个旋转步骤中试样引起的 X 射线的衰减。计算机断层扫描系统生成立方体的三维数字结构。</li>
		<li>用黑白二进制处理技术识别数字立方体结构中的钢纤维。然后获得了描述钢纤维分布的数字图像。</li>
		<li>用图像分析法确定所有钢纤维的坐标。</li>
		<li>根据其坐标计算各钢纤维的方向。</li>
		<li>用方程 (3) 计算纤维的取向效率系数。</li>
	</ol>
</li>
</ol>

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作者没有什么可透露的。

本研究开发的电磁螺线管有一室测量250×250×750毫米, 不能容纳全尺寸结构元素。虽然会议厅的大小限制了设置的应用, 本文提出的概念和协议将激励进一步开发一个完整的尺寸设置, 制造 ASFRC 元素, 特别是预制元件。
达到适当粘度的新鲜砂浆是控制 ASFRCs 质量的关键因素, 因为钢纤维的对准是由需要克服新砂浆粘性阻力的磁力驱动的。粘性电阻受新砂浆粘度的制约。砂浆的粘度...

钢纤维掺入混凝土是克服脆性的固有弱点, 提高混凝土抗拉强度的有效途径1。在过去的几十年中, 钢纤维混凝土已被广泛的研究和广泛应用于该领域。钢纤维混凝土在抗裂性、抗拉强度、断裂韧性、断裂能等方面优于混凝土2在钢纤维混凝土中, 钢纤维随机分散, 从而均匀分散纤维在各个方向的增强效率。然而, 在一定的荷载条件下, 混凝土中只有部分钢纤维对结构构件的性能有贡献, 因为纤维的增强效率要求它们与主拉应力在结构。例如, 当钢纤维混凝土中含有随机分布的钢纤维来制备梁时, 某些钢纤维, 特别是与主拉应力方向平行的钢筋, 将对提高效率, 而垂直于主拉应力方向的那些将不会对提高效率作出贡献。因此, 寻找一种将钢纤维与混凝土主要拉应力方向相对准的方法, 是实现钢纤维最高加固效率的必要条件。
定位效率因子, 定义为沿拉伸应力方向的投影长度与纤维实际长度的比值, 通常用来表示钢筋纤维3、4 的增强效率..根据这一定义, 与拉伸应力方向一致的纤维取向效率系数为 1.0;与拉伸应力垂直的纤维是0。倾斜纤维在0和1.0 之间有一个取向效率因素。分析结果表明, 混凝土中随机分布钢纤维的取向效率系数为 0.4054, 而普通钢纤维混凝土的试验范围为0.167 到 0.5005,6.显然, 如果混凝土中的短钢纤维对齐, 并且与拉伸应力方向相同, 则钢纤维将具有最高的加固效率, 试样的拉伸性能最佳。
自二十世纪八十年代以来, 一些成功的尝试准备对齐钢纤维钢筋混凝土。在 1984年, 沈7在铸钢纤维增强水泥基复合材料 (纤维混凝土) 梁的底层应用了一个电磁场, x 射线检测分析表明, 钢纤维的排列良好。在 1995年, 拜耳8和 Arman9获得专利的方法, 以制备对齐钢纤维钢筋混凝土使用磁场。山本等。10考虑了钢纤维在混凝土中的取向主要受铸造方法的影响, 并试图通过保持新混凝土从恒定方向向模板流动的方式获得对齐钢纤维混凝土。徐11试图将钢纤维从一个恒定的方向喷出, 使其在喷射混凝土中保持一致。圣乔瓦尼罗和维纳12试图用离心铸造的方式使长钢纤维的混凝土极。试验研究表明, 钢纤维混凝土与随机分布的钢纤维混凝土相比具有明显的优越性。
最近, 米歇尔斯等。13和亩等。14已成功开发了一组采用电磁场的排列钢纤维增强水泥基复合材料 (ASFRCs)。在这些研究中, 各种螺线管被用来提供一个统一的磁场, 使钢纤维在不同尺寸的砂浆试样中进行对准。螺线管有一个空心长方体室, 可以容纳预定大小的样品。当电磁线圈连接到直流 (DC), 一个统一的磁场是在腔内创建一个固定的方向, 这与螺线管的轴对齐。根据电磁15原理, 磁场可以驱动铁磁纤维在新鲜砂浆中旋转和对准。砂浆的适当的可加工性对于允许钢纤维在新鲜砂浆中旋转是至关重要的。高粘度可能会导致砂浆中钢纤维的对准困难, 而低粘度可能导致纤维的离析。
本文介绍了 ASFRC 试样的制备细节, 并对 ASFRC 和钢纤维混凝土的弯曲性能进行了试验研究。预计 ASFRC 比钢纤维混凝土具有更高的抗弯强度和韧性。因此, ASFRC 有可能比钢纤维混凝土在抗拉应力和抗裂性能方面具有优越性, 如用作覆盖混凝土、路面等.
利用弯曲试验后的断裂试样, 通过观测裂隙剖面, 利用 X 射线扫描计算机层析分析16、17 , 研究了试样中钢纤维的取向。,18. 报告了 ASFRCs 的力学性能, 包括其弯曲强度和韧性, 并与非电磁处理的 SFRCs 进行了比较。

<table><tbody><tr><td>Cement</td><td>Tangshan Jidong Cement Co., Ltd.</td><td>P&amp;times;O 42.5</td><td>Oridnary Portland Cement</td></tr><tr><td>Sand</td><td></td><td>River sand</td><td>Fineness modulus is 2.4</td></tr><tr><td>Superplasticizer</td><td>Subote New Materials Co., Ltd.</td><td>PCA-III</td><td>Polycarboxylated type, water reducing ratio is 35%</td></tr><tr><td>Steel fiber</td><td>Tianjin Hengfeng Xuxiang New Metal Materials Co., Ltd.</td><td>Round straight</td><td>Diameter 0.5mm, length 25mm</td></tr></tbody></table>

preparation of aligned steel fiber reinforced cementitious composite and its flexural behavior

这项工作的目的是提出一种方法, 灵感的方式, 罗盘针保持一致的方向, 在地球的磁场的作用下, 制造的水泥基复合材料加强了对齐钢纤维。将均匀的电磁场应用于含短钢纤维的新鲜砂浆中, 通过将短钢纤维与磁场相对准, 使钢纤维增强水泥基复合材料 (ASFRC) 制备。通过对断裂剖面中钢纤维的计数和 X 射线计算机断层分析, 对钢纤维在硬化 ASFRC 中的对准程度进行了评价。这两种方法的结果表明, ASFRC 中的钢纤维高度排列, 而非磁处理复合材料中的钢纤维是随机分布的。所对的钢纤维具有更高的增强效率, 因此复合材料的抗弯强度和韧性明显增强。因此, ASFRC 比钢纤维混凝土更优越, 它能承受较大的拉应力, 更有效地抵御开裂。

由三点弯曲试验确定的 ASFRCs 和 SFRCs 的弯曲强度如图 5所示。ASFRCs 的抗弯强度高于所有纤维用量的 SFRCs。ASFRCs 的抗弯强度分别为0.8%、1.2%、2.0% 纤维体积分数的88%、71% 和57% 以上的 SFRCs。这些结果意味着, 对齐钢纤维比随机分布的钢纤维更有效地加强胶凝基体。
图 6显示?...

Watch this Scientific Journal Video about Preparation of Aligned Steel Fiber Reinforced Cementitious Composite and Its Flexural Behavior at JoVE.com

Preparation of Aligned Steel Fiber Reinforced Cementitious Composite and Its Flexural Behavior

本协议描述了一种采用均匀电磁场制造对齐钢纤维增强水泥基复合材料的方法。对钢纤维增强水泥基复合材料具有优异的力学性能。

定向钢纤维增强水泥基复合材料的制备及其弯曲性能研究

The aim of this work is to present an approach, inspired by the way in which a compass needle maintains a consistent orientation under the action of the ...

preparation-aligned-steel-fiber-reinforced-cementitious-composite-its

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11.0K 次观看.  Hebei University of Technology. 本协议描述了一种采用均匀电磁场制造对齐钢纤维增强水泥基复合材料的方法。对钢纤维增强水泥基复合材料具有优异的力学性能。

视频: Preparation of Aligned Steel Fiber Reinforced Cementitious Composite and Its Flexural Behavior

Experimental Implementation of a New Composite Fabrication Method: Exposing Bare Fibers on the Composite Surface by the Soft Layer Method

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional component that should have high electrical conductivity, high mechanical properties, and high productivity.
In this regard, a carbon fiber/epoxy resin composite can be an ideal material to replace the conventional graphite bipolar plate, which often leads to the catastrophic failure of the entire system because of its inherent brittleness. Though the carbon/epoxy composite has high mechanical properties and is easy to manufacture, the electrical conductivity in the through-thickness direction is poor because of the resin-rich layer that forms on its surface. Therefore, an expanded graphite coating was adopted to solve the electrical conductivity issue. However, the expanded graphite coating not only increases the manufacturing costs but also has poor mechanical properties.
In this study, a method to expose fibers on the composite surface is demonstrated. There are currently many methods that can expose fibers by surface treatment after the fabrication of the composite. This new method, however, does not require surface treatment because the fibers are exposed during the manufacture of the composite. By exposing bare carbon fibers on the surface, the electrical conductivity and mechanical strength of the composite are increased drastically.

A protocol to expose bare fibers on the composite surface by eliminating resin rich area is presented. The fibers are exposed during fabrication of the composites, not by the post surface treatment. The exposed carbon composites exhibit high electrical conductivity in the through-thickness direction and high mechanical property.

一种新的复合制备方法的实验实现: 用软层法对复合材料表面裸露纤维进行曝光

The bipolar plate is a key component in proton exchange membrane fuel cells (PEMFCs) and vanadium redox flow batteries (VRFBs). It is a multi-functional ...

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工程学

Installation Method to Enhance Quality Control for Fiber Reinforced Polymer Spike Anchors

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they can delay or even prevent debonding failure. However, a major concern faced by designers is the premature failure of the anchors due to stress concentration. Poor installation quality and preparation of the clearance holes can result in stress concentration that provokes this premature failure. This paper deals with an installation method that aims to reduce the impact of the stress concentration and to provide a proper quality control of the preparation of the drill hole. The method involves three parts: the drilling and cleaning of the holes, the smoothing of the hole edges with a customized drill bit, and the installation of the anchor itself, including the impregnation of the anchor dowel and its insertion. Anchor fans (the free length of the spikes) are then bonded to the external FRP reinforcement. For the end anchorage, and in the case of reinforcements with multiple plies, it is recommended that the anchor fan be inserted between two plies to assist the stress-transfer mechanism. 
The proposed procedure is complemented with a design approach for spike anchors, based on an extensive database. It is proposed that the design follow a number of steps, namely: selection of the anchor diameter and subsequent tensile strength of the connector (that is to say, the anchor before fanning out the free end), evaluation of the reduction in the tensile strength due to bending, provision of enough embedment to prevent slippage failure, and consideration of the number and spacing of anchors for a given reinforcement. In this sense, it should be noted that further research is needed in order to obtain a general expression for the contribution of spike anchors to overall bond strength of FRP reinforcements.

This manuscript presents a method for controlling the quality of installation for spike anchors designed to delay delamination of externally bonded fiber reinforced polymers. The protocol includes the preparation of the drill hole and the insertion process. The most influential parameters on the efficiency of the anchors are discussed.

提高纤维增强聚合物穗锚质量控制的安装方法

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they ...

Cutting Procedures, Tensile Testing, and Ageing of Flexible Unidirectional Composite Laminates

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in the National Institute of Justice Standard-0101.06, UD laminates showed visual signs of delamination and reductions in V50, which is the velocity at which half of the projectiles are expected to perforate the armor, after ageing. A better understanding of the material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed from these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.

The goal of the study was to develop protocols to prepare consistent specimens for accurate mechanical testing of high-strength aramid or ultra-high-molar-mass polyethylene-based flexible unidirectional composite laminate materials and to describe protocols for performing artificial ageing on these materials.

柔性单向复合层压板的切割程序、拉伸测试和老化

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, ...

Determination of the Mechanical Properties of Flexible Connectors for Use in Insulated Concrete Wall Panels

This document contains recommendations for performing a non-standard, double-shear test suitable for both continuous and discrete insulated concrete sandwich wall panels (ICSWPs). Such a standardized test does not exist, but several iterations of this and similar tests have been performed in the literature to varying degrees of success. Further, the tests in the literature are rarely-if ever-described in detail or discussed at length with respect to the testing, data analysis, or safety procedures. A test specimen configuration is recommended herein, and variations are discussed. Important mechanical properties are identified from the load versus displacement data, and their extraction is detailed. The use of test data for design, such as for determining the stiffness of the connectors, is briefly demonstrated to show how ICSWP deflection and cracking behavior may be calculated. The strength behavior of panels may be determined using the full load versus displacement curve or only the maximum connector strength. Shortcomings and unknowns are acknowledged, and significant future work is delineated.

We propose a testing protocol that can be combined with widely available analytical methods to assess the mechanical properties of shear connectors for use in the design of insulated concrete wall panels to predict full-scale insulated panel behavior.

用于隔热混凝土墙板的柔性连接器的机械性能测定

This document contains recommendations for performing a non-standard, double-shear test suitable for both continuous and discrete insulated concrete ...

纤维复合材料层压板的制造和机械性能评估

Measuring the Mechanical Properties of Glass Fiber Reinforcement Polymer Composite Laminates Obtained by Different Fabrication Processes

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the forming pressure, the mass fraction of fiber is reduced and lots of air bubbles are trapped inside, resulting in low-quality laminates (low stiffness and strength). The wet hand lay-up/vacuum bag (WLVB) process for the fabrication of composite laminates is based on the traditional wet hand lay-up process, using a vacuum bag to remove air bubbles and provide pressure, and then carrying out the heating and curing process. 
Compared with the traditional hand lay-up process, laminates manufactured by the WLVB process show superior mechanical properties, including better strength and stiffness, higher fiber volume fraction, and lower void volume fraction, which are all benefits for composite laminates. This process is completely manual, and it is greatly influenced by the skills of the preparation personnel. Therefore, the products are prone to defects such as voids and uneven thickness, leading to unstable qualities and mechanical properties of the laminate. Hence, it is necessary to finely describe the WLVB process, finely control steps, and quantify material ratios, in order to ensure the mechanical properties of laminates. 
This paper describes the meticulous process of the WLVB process for preparing woven plain patterned glass fiber reinforcement composite laminates (GFRPs). The fiber volume content of laminates was calculated using the formula method, and the calculated results showed that the fiber volume content of WL laminates was 42.04%, while that of WLVB laminates was 57.82%, increasing by 15.78%. The mechanical properties of the laminates were characterized using tensile and impact tests. The experimental results revealed that with the WLVB process, the strength and modulus of the laminates were enhanced by 17.4% and 16.35%, respectively, and the specific absorbed energy was increased by 19.48%.

作者聚焦：使用湿法手糊/真空袋工艺提高纤维复合材料层压板质量 

This paper describes a fabrication process for fiber-reinforced polymer matrix composite laminates obtained using the wet hand lay-up/vacuum bag method.

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

The traditional wet hand lay-up process (WL) has been widely applied in the manufacturing of fiber composite laminates. However, due insufficiency in the ...

Tension Test of Fiber-Reinforced Polymeric Materials

Source:&#160;Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA
Fiber-reinforced polymeric materials (FRP) are composite materials that are formed by longitudinal fibers embedded in a polymeric resin, thereby creating a polymer matrix with aligned fibers along one or more directions. In its simplest form, the fibers in FRP materials are aligned in an orderly, parallel fashion, thus imparting orthotropic material characteristics, meaning that the material will behave differently in the two directions. Parallel to the fibers, the material will be very strong and/or stiff, whereas perpendicular to the fibers will be very weak, as the strength can only be attributed to the resin instead of the whole matrix.
An example of this unidirectional configuration is the commercially available FRP reinforcing bars, which mimic the conventional steel bars used in reinforced concrete construction. FRP materials are used both as stand-alone structures such as pedestrian bridges and staircases, and also as materials to strengthen and repair existing structures. The thin, long plates are often epoxied to existing concrete structures to add strength. In this case, the FRP bars act as external reinforcement. The FRP bars and plates are lighter and more corrosion resistant, so they are finding applications in bridge decks and parking garages, where de-icing slats lead to rapid deterioration of conventional bars.
In this laboratory exercise, the tensile behavior of a unidirectional specimen will be studied, with emphasis on its ultimate strength and deformation capacity. The behavior of the specimen is expected to be elastic until failure, which is expected to occur in a sudden and explosive manner. This behavior should be contrasted with those of ductile steels, which exhibit extensive deformation capacity and strain hardening before failure.

Uniaxial Tension Test of Fiber-Reinforced Polymeric Materials

纤维增强高分子材料的拉伸试验

Source:&#160;Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA
Fiber-reinforced polymeric materials (FRP) are ...

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Ceramic-matrix Composite Materials and Their Bending Properties

Source: Sina Shahbazmohamadi and <a href="https://www-jove-com.bdigitaluss.remotexs.co/author/Peiman_Shahbeigi-Roodposhti">Peiman Shahbeigi-Roodposhti-Roodposhti</a>, School of Engineering, University of Connecticut, Storrs, CT
Bones are composites, made of a ceramic matrix and polymer fiber reinforcements. The ceramic contributes compressive strength, and the polymer provides tensile and flexural strength. By combining ceramic and polymer materials in different amounts, the body can create unique materials tailored for a specific application. As biomedical engineers, having the ability to replace and replicate bone due to disease or traumatic injury is a vital facet of medical science.
In this experiment we will create three different ceramic-matrix composites with plaster of Paris (which is a calcium sulfate compound), and allow them to undergo three-point bending test in order to determine which preparation is the strongest. The three composites are as follows: one comprised only of plaster of Paris, one with chopped glass shards mixed in a plaster matrix and lastly a plaster matrix with a fiberglass network embedded within it.

Bending Strength and 3-Point Bending Test of Ceramic Materials

陶瓷基质复合材料及其弯曲特性

Source: Sina Shahbazmohamadi and Peiman Shahbeigi-Roodposhti-Roodposhti, School of Engineering, University of Connecticut, Storrs, CT
Bones are ...

材料工程

Tests of Hardened Concrete in Tension

Source:&#160;Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA
In a previous laboratory focused on concrete in compression, we observed that concrete can withstand very large stresses under uniaxial compressive forces. However, the failures observed were not compressive failures but failures along shear planes where maximum tensile forces occur. Thus, it is important to understand the behavior of concrete in tension and particularly its maximum strength as that will govern both its ultimate and service behavior. From the ultimate standpoint, combinations of tension and shear stresses will lead to cracking and immediate and catastrophic failure. For that reason, concrete is seldom if ever used in an unreinforced condition in structural applications; most concrete members will be reinforced with steel so that these cracks can be stopped and the crack widths limited. The latter is important from the serviceability standpoint because controlling crack widths and distribution is the key to durability, as this will impede deicing salts and similar chemicals from penetrating and corroding the reinforcing steel.
The objectives of this experiment are threefold: (1) to conduct tensile split cylinder tests to determine concrete tensile strength, (2) to conduct beam tests to determine concrete tensile strength, and (3) to demonstrate the influence of steel reinforcement on behavior by comparing the behavior of lightly reinforced beam with an unreinforced one.

Split Tension Test and Beam Tension Test for Hardened Concrete

硬化混凝土的拉伸试验

Source:&#160;Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA
In a previous laboratory focused on concrete ...

定向钢纤维增强水泥基复合材料的制备及其弯曲性能研究

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此视频中的章节

一种新的复合制备方法的实验实现: 用软层法对复合材料表面裸露纤维进行曝光

提高纤维增强聚合物穗锚质量控制的安装方法

柔性单向复合层压板的切割程序、拉伸测试和老化

用于隔热混凝土墙板的柔性连接器的机械性能测定

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

测量通过不同制造工艺获得的玻璃纤维增强聚合物复合层压板的机械性能

纤维增强高分子材料的拉伸试验

陶瓷基质复合材料及其弯曲特性

硬化混凝土的拉伸试验