服裝行業網路營銷的國外發展

1、服裝行業，在世界的前景怎麼樣？

——原標題：2018年全球服裝零售行業市場現狀與發展趨勢分析 零售額穩步增長

全球服裝零售規模穩步擴大

受全球經濟增長的推動，人們可支配收入穩步提升，進而推動全球服裝零售業規模不斷壯大。根據Frost&Sullivan數據統計，2018年，全球服裝零售業總零售額達14382億美元，2014-2018年間復合年增長率為4.2%。

分類別來看，全球服裝可分為下裝、襯衫、運動休閑服、內衣、毛衣、外套、定製及其他。2018年，全球服裝零售市場主要以下裝及襯衫為主，零售額均超過2300億美元，占服裝零售總零售額比重分別為16.3%、16.0%。

從增速角度比較，2014-2018年期間，運動休閑服零售額增長更為明顯，其復合年增長率達5.6%，主要得益於全球健康及健身潮流日益盛行以及著裝規范的普遍放鬆，未來運動休閑服仍有巨大增長潛力。

分定位來看，全球服裝大致可分為奢侈、高端(橋接、優良)、中端、大眾。目前，全球服裝零售市場還是以中端及大眾品牌為主，2018年零售額分別達4674億美元、4143億美元，佔比分別為32.5%、28.8%。

增速方面，高端市場增長顯著，在2014-2018年間，盡管市場份額不大，但橋接及優良市場品牌的復合年增長率分別達4.5%、4.9%，這得益於新興品牌的風靡。新興品牌較迎合大眾消費市場的品牌，有著更高的溢價。

分品牌來看，傳統品牌占據了全球服裝零售市場約87.6%的份額，而網路原生品牌及平台約佔12.4%。2014-2018年，傳統品牌的全球服裝零售額從10755億美元增至12599億美元，復合年增長率為4.0%;而同期網路原生品牌零售額從1444億美元增至1783億美元，復合年增長率達5.4%，高出傳統品牌1.4個百分點。

全球服裝零售呈現五大趨勢

未來，全球服裝零售行業將呈現以下趨勢：一是全球消費者對時尚商品的需求將進一步升級為有趣、隨時可用、可持續且價格合理，因此越來越多的消費者正轉向服裝租賃和二手服裝，隨著二手、租賃等業務模式的不斷發展，品牌獨家銷售或許不再成為消費者的購物路徑。

二是年輕的一代，包括Z世代和千禧一代將成為服裝零售的購買主力軍。這一購物主力軍越來越多的依賴自己的購物習慣，並且看重商品、品牌與自己的價值觀是否苟同。

三是快速已經逐漸成為了行業標准，尤其是對在線零售而言更是如此。除了像電商巨頭亞馬遜推出了快速發貨、配送等一站式服務外，越來越多的平台正在試圖加快購物流程，如將購物功能在社交媒體埠進行整合以及視覺識別購物等。從技術到服務，及時快速的購物體驗正在成為全新的消費指標。

四是顛覆將成全球服裝零售行業的關鍵詞之一。外部來看，社媒勢頭和技術發展催生了大批新興品牌和商業模式，而這些角色正在挑戰傳統行業現狀。與此同時，為了在需求旺盛的年輕消費者中競爭並保持相關性，越來越多的傳統品牌正在進行自我顛覆以呼應新趨勢，試圖打造自己的全新品牌、產品和商業模式。

五是服裝款式設計和潮流更替不再是一個漫長的過程，品牌和商家們將利用技術加快產品線更迭的頻率。例如，自動化數據工具將有助於企業採用靈活的訂單生產周期，更快地響應市場趨勢和消費者需求。

——以上數據來源請參考於前瞻產業研究院發布的《中國服裝零售行業市場前瞻與投資戰略規劃分析報告》。

2、當前網路營銷國內外研究水平

網站優化已經成為網路營銷經營策略的必然要求。如果在網站建設中沒有體現網站優化和搜索引擎優化的基本思想，在網路營銷水平普遍提高的網路營銷環境中是很難獲得競爭優勢的。新競爭力提供最專業的網站優化分析建議與網站優化解決方案。新競爭力的網站優化思想：通過對網站功能、網站結構、網頁布局、網站內容等要素的合理設計，使得網站更好的向用戶傳遞網路營銷信息，發揮最大的網路營銷價值。網站優化是一項系統性和全局性的工作，包括對用戶的優化、對搜索引擎優化、對運營維護的優化。
新競爭力對網站優化思想及網站優化方法有深入的研究，發表了大量廣為傳播的網站優化研究文章和針對多個行業的網站優化狀況研究報告，無論對新網站的優化策略還是運營中網站的優化升級均有獨到的認識和豐富的實踐經驗。新競爭力網路營銷管理顧問為國內外眾多網站提供了針對性的網站優化解決方案並取得了顯著效果（其中包括多家知名B2B電子商務網站、B2C網站、行業門戶網站、WEB2.0網站和各類企業網站）。

新競爭力的網路營銷專家團隊是網站優化思想的締造者（在馮英健專著《網路營銷基礎與實踐》第二版有詳細描述），同時新競爭力也是中國互聯網協會網站建設指導規范的發起單位，承擔中國互聯網協會網站建設指導規范的制定工作。新競爭力的網站優化方案遵照國際WEB標准和中國中國互聯網協會網站建設指導規范制定，居於國際領先地位。新競爭力網站優化解決方案是從網站運營策略層面對網站進行的整體優化，是關繫到網站運營成效的全局性的工作，是其他片面的搜索引擎優化和SEO排名所無法相提並論的。系統的網站優化可以達到最好的、持久的搜索引擎優化效果，並且可以為用戶提供最有價值的信息和服務，而單純的搜索引擎排名僅僅是為了搜索引擎檢索，其效果是局部的、短暫的，也可能是後患無窮的。

新競爭力網路營銷管理顧問（www.jingzhengli.cn）建議，如果您正在或者將要建設一個新的網站，最理想的情況是在網站策劃階段就將網站優化的基本思想融入到網站建設方案中，並在網站建設過程中貫徹實施。這樣可以讓新發布的網站直接從高起點開始運營，可以大大提高網站運營的效果，也節省了網站優化改造的費用。 如果您的網站在運營推廣中遇到網站訪問量增長的瓶頸等方面的問題，新競爭力建議您盡可能早的實施網站優化策略，以免造成無法彌補的損失。如果不能比競爭者早一步，至少也不應該落後太多。

3、國外網路營銷發展現狀

多數國家已進入信息時代，網路接入和先進的終端設備給互聯網營銷提供了一個良好的發展環境。下面舉幾個例子來解釋下國外網路營銷的現狀：

美國也在不斷地完善互聯網營銷的法律法規體系來給消費者創造一個良好的網路購物環境。

新加坡不僅及時制定相關政策法規，引導企業進行信息化基礎設施建設，還積極推動網路營銷的發展，消除電子商務發展的安全障礙，並確保網上交易者獲得全面、安全和高質量的服務。

以電子產品著稱的日本也正在積極實施互聯網營銷， 而這對於加大電子產品在全球的市場佔有份額，促進企業轉型，助推經濟增長起到了關鍵性的作用。

由於互聯網營銷因不受空間、地域、時間限制的優勢， 也逐漸成為重要的市場交易模式，網路營銷已成為經濟最具有活力的增長點。

4、我國和國外的服裝行業發展現狀？

由於市場的開放，出口紡織品數量的增加，現行標准已不能滿足產品質量和市場變化的要求。大多數的合資企業、獨資企業以及有出口任務的企業，採用協議標准，按供需雙方的協議合同考核和驗收產品。而習慣於依賴國家標准或行業標準的企業，聲稱沒有標准制約了企業的產品開發。

縱觀國內紡織品市場尤其是製成品和服裝市場上涌現出的很多被消費者認可的名牌產 品，其生產企業無一不是執行嚴格的技術標准和檢驗制度，無一不是採用優於國家標准和行業標準的企業內控標准。名牌產品是以優良的產品質量為基礎，以高水準的標准為支撐，這些共識和實踐對促進紡織工業的技術進步和產品質量的提高起到了積極的作用。

我國的紡織品標准現狀

與紡織工業的發展相適應，我國紡織標准化工作不斷地得到完善和提高，取得不小的成績，紡織標准化工作為適應國家的經濟建設和紡織工業的發展需要做出了應有的貢獻。表現在：

1、從紡織材料到製成品和服裝的標准已形成體系和規模。截止2002 年底，共有紡織品和服裝標准885 個(不包括纖維原料標准)，其中國家標准383個，紡織行業標准502個，形成了以產品標准為主體，以基礎標准相配套的紡織標准體系，包括術語符號標准、試驗方法標准、物質標准和產品標准四類，涉及纖維、紗線、長絲、織物、紡織製品和服裝等內容，從數量和覆蓋面上基本滿足了紡織品和服裝的生產和貿易需要。

2、紡織品標準的采標率列為前位，基礎標准與國際接軌。根據國家有關部門的統計，對國際標準的采標率，國內平均水平約為44％，而紡織品的采標率達80％。ISO中有關紡織品和服裝的標准約有280多個。紡織行業對這些國際標准進行了研究，已經在不同程度上採用或已列入年度採用計劃。除採用國際標准外，還不同程度的採用了國外先進國家的標准，如美國標准、英國標准、德國標准和日本標准等。特別是基礎的、通用的術語標准和方法標准基本上採用了國際標准和國外先進標准，使制定的國家標准達到了國際標准或相當於國際標準的水平。

3、各類標准發揮了巨大作用。與國際接軌的基礎標准，對統一紡織工業科技術語、統一紡織材料和產品的檢測手段、統一規范產品的性能指標起到了重要的作用。特別是依據這些檢測方法試驗出具的數據不僅在全國范圍內具有可比性，而且也得到了國外客戶的認可，對紡織品貿易起到了不可低估的作用。制定的大量的紡織產品標准，適應了產品的發展和需要，解決了無標生產的問題，為企業的大量產品進入市場提供了技術依據。

4、企業的標准化理念對提高產品質量起到了關鍵作用。從1989年《標准化法》實施以來，企業的標准化工作逐步加強，參與標准化的熱情越來越高漲。

但是，隨著近年來市場經濟的發展，現有的標准體制和標准內容逐漸顯現出了其弊端，具體表現在：

1、在原有計劃經濟體制下，我國的紡織產品標準是生產型的，標準的制定以指導生產為主要出發點，技術要求與生產工藝緊密相聯，指標定的過細過死，特別是標準的制修訂速度滯後於產品的開發速度。有些企業認為標准水平太低，而有的企業卻認為標准指標過高，形成了對標準的不同要求和評價。

2、隨著紡織製品的成品化成為趨勢，消費者對服飾和家庭裝飾水平要求的提高，原料質量與製成品質量不配套的問題日益突出。例如，面料標準的色牢度差，水洗尺寸變化率大，缺乏實用性能考核指標等，由於標准不銜接引起的糾紛時有發生，消費者的投訴難以得到解決。

3、以前采標的指導思想是結合中國國情，考慮到國內現有設備和工藝條件，因此使我國采標的多數標准為「 非等效」或「參照」。除基礎標准接軌程度較高外，盡管有不少的產品標准前言中寫明是採用國際或國外先進標准，但僅有少數指標甚至個別指標與國外標准一致，或採用的試驗方法是採用國際標準的，因此，大多數產品標準的指標和水平沒有真正與國外接軌。

4、由於市場的開放，出口紡織品數量的增加，現行標准已不能滿足產品質量和市場變化的要求。大多數的合資企業、獨資企業以及有出口任務的企業，採用協議標准，按供需雙方的協議合同考核和驗收產品。而習慣於依賴國家標准或行業標準的企業，聲稱沒有標准制約了企業的產品開發。

與國外先進標準的差距

首先，形成的標准體系不同。ISO或國外的國家層面上的紡織標准，主要內容是基礎類標准，重在統一術語，統一試驗方法，統一評定手段，使各方提供的數據具有可比性和通用性。形成的是以基礎標准為主體，再加上以最終用途產品配套的相關產品標準的標准體系。在產品標准中僅規定產品的性能指標和引用的試驗方法標准。對大量的產品而言，國外是沒有國家標準的，主要由企業根據產品的用途或購貨方給予的價格，與購貨方在合同或協議中規定產品的規格、性能指標、檢驗規則、包裝等內容。

我國現行的紡織產品標准有不少是計劃經濟體制時的產物，形成的標准體系以原料或工藝劃分的產品標准為主，目前主要分為棉紡織印染、毛紡織品、麻紡織品、絲產品、針織品、線帶、化纖、色織布。近年來也以用途制定標准，但所佔比例極小。標准中除性能指標外，還包括出廠檢驗、型式檢驗、復驗等檢驗規則的內容，形成了各類原料產品「紗 線―――本色布―――印染布」的標准鏈。

其次，標准發揮的職能不同。國外將國家層面上的公開標准作為交貨、驗收的技術依據，從指導用戶購買產品的角度和需要來制定，人們稱之為貿易型標准。企業標准才是作為組織生產的技術依據。這種貿易型標準的技術內容規定的比較簡明，比較籠統，比較靈活。

與之相反，我國大多數的產品標準的職能是用以組織生產的依據，從指導企業生產的角度的需要來確定，人們稱之為生產型標准。為了便於企業生產，標准在技術內容方面，一般都規定的比較具體，比較詳細，比較死。

隨著市場經濟的發展，紡織產品的新品種不斷涌現，決定了簡明靈活的貿易型標准更能符合市場的需要。我國的生產型標准范圍較窄，覆蓋的產品種類較少，造成標準的數量不少，但仍跟不上產品的發展速度。

第三，標准水平有差距。由於標準的職能不同，標准技術內容，如在考核項目的設置上，在性能指標的水平上等均有一定的差距。

國外根據最終用途制定的面料標准，考核項目更接近於服用實際，如耐磨、紗線滑移阻力、起毛起球、耐光色牢度等。我國的面料標准還缺少諸如接縫滑移、起毛起球、乾洗尺寸變化、耐光色牢度等考核指標，不能適應人們對服用產品舒適美觀性的要求。對服裝的考核主要側重服裝的規格偏差、色差、縫制、疵點等外觀質量，判定產品等級時忽略了 構成服裝的主要元素―――面料和里料。

我國按生產型標准理念制定的標准，不能適用貿易關系超出生產方和購貨方這種情況，例如，按染料類別和工藝制定不同的色牢度等級，在貿易交貨驗收中確定考核依據較為困難。而國外標準的質量指標控制嚴格，色牢度普遍高於國內指標1～1.5級，尤其是摩擦色牢度相差更多。

翻開產品標准，為數不少的標准文本中寫有「優等品相當於國際先進水平，一等品相當於國際一般水平」等，實際上僅是個別單項指標水平達到國際水平，但綜合性能達不到；還有個別標為采標的標准，其內容與國外標准相差甚遠。

第四，國外標准形成了技術壁壘。隨著貿易壁壘逐漸減小，各國都在藉助於TBT有關條款規定，製造技術壁壘。而製造技術壁壘的有效途徑就是法規和標准。歐洲議會和歐盟委員會2002年7月19日共同頒布的指令2002 ／61／EC―《對歐盟委員會關於限制某些危險物質和制劑(偶氮染料)的銷售和使用的指令76／769／EEC的第 19次修改令》，連同歐盟委員會2002年5月15日頒布的關於修改並發布授權紡織產品使用歐共體生態標簽(Ec o-label)的決定(2002／371／EC)，歐盟在為紡織品和日用消費品的市場准入構築完整的「綠色屏障」 方面邁出了兩個重大的步伐。中國作為全球最大的紡織品生產和出口國，可能受到的影響顯然是不可低估的。

由於諸多原因，在進口紡織品中不乏有劣質產品和不合格產品。但我國技術法規和強制性標准欠缺，不能有效監督進口產品的質量。2000 年就著手制定的《紡織品基本安全技術要求》至今還未批准，對國外的不良產品起不到抵擋作用。

5、誰知道國外網路營銷發展現狀？

國外的網路廣告模式發展狀況。
網路廣告是指利用國際互聯網這種載體，通過圖文或多媒體方式，發布的贏利性商業廣告，是在網路上發布的有償信息傳播。
美國作為網路廣告的發源地，其網路廣告在廣告市場仍占較少部分，但網路廣告市場規模增長速度不容小視；日本網路廣告具有受到其傳統市場營銷方式的影響大的特徵，網路廣告與電視廣告以及電台廣告的呈現融合趨勢；韓國的網路廣告市場規模基本保持著穩步增長的趨勢；在歐洲，英國網路廣告發展速度最快，歐洲網路廣告市場的廣告主主要為IT類和通信類企業。
07年的今天，國內外談論的不再是簡簡單單的網路廣告了，網路廣告經過7年的發展，大家的追求不再是做不做網路廣告的選擇，而是如何選擇更好的網路廣告模式了。來電付費廣告模式是現在大家所津津樂道的，來電付費是在網路廣告的基礎上增加了客戶與企業主的電腦語音溝通的過程，而它的費用是按照電話的時長而定的。美國AOL、Findwhat.com, Google等老牌互聯網巨頭，紛紛試水通話付費廣告業務，受到中小企業，尤其是從事批發、貿易等廣告主的青睞，行業發展勢頭強勁。而在中國尚處於萌芽期，希望向萬維聯訊等技術提供商能讓來電付費的推廣工作做到最好。希望百度、雅虎和google等網站能再次譜寫網路新的歷史篇章。

6、服裝網路營銷國內外研究現狀怎麼寫

?

7、中小型企業網路營銷 國內外研究現狀

現在中小企業的網路營銷現狀跟在線下開個實體店，店裡裝修很一般，版也沒有做點引導客戶的措施，權導致雖然進來看的人很多，但銷量很差，最後不得不放棄，是差不多的。現在幾乎所有的企業都是在做百度競價、SEO、外推等技術，確實帶來了大量的人氣，但成交率太低，或者說入不敷出也不為過。
總結：中小企業做網路營銷不是做個網站，然後開始推廣就行了的，如果這樣，只會白白浪費大量的人力、物力、財力。網路營銷是一個長期的過程、是一個積累的過程，在實際操作的過程中難免會遇到各種各樣的問題，要做的就是分析數據掌握對的方法，堅持下去。

8、高分求[國際服裝發展現狀和品牌服裝營銷]方面的外文文獻

這是一片寫的不錯的

Effect of fiber architecture on flexural characteristics and fracture of fiber-reinforc

Vistasp M. Karbharia, Corresponding Author Contact Information, E-mail The Corresponding Author and Howard Strasslerb
aMaterials Science & Engineering Program, and Department of Structural Engineering, MC-0085, University of California San Diego, Room 105, Building 409, University Center, La Jolla, CA 92093-0085, USA.
bDepartment of Restorative Dentistry, Dental School, University of Maryland, Baltimore, MD, USA
Received 10 December 2005; revised 25 June 2006; accepted 31 August 2006. Available online 7 November 2006.

Abstract

Objective

The aim of this study was to compare and elucidate the differences in damage mechanisms and response of fiber-reinforced dental resin composites based on three different brandsnext term under flexural loading. The types of reinforcement consisted of a unidirectional E-glass prepreg (Splint-It from Jeneric/Petron Inc.), an ultrahigh molecular weight polyethylene fiber based biaxial braid (Connect, Kerr) and an ultrahigh molecular weight polyethylene fiber based leno-weave (Ribbond).

Methods

Three different commercially available fiber reinforcing systems were used to fabricate rectangular bars, with the fiber reinforcement close to the tensile face, which were tested in flexure with an emphasis on studying damage mechanisms and response. Eight specimens (n = 8) of each type were tested. Overall energy capacity as well as flexural strength and molus were determined and results compared in light of the different abilities of the architectures used.

Results

Under flexural loading unreinforced and unidirectional prepreg reinforced dental composites failed in a brittle previous termfashion,next term whereas the braid and leno-weave reinforced materials underwent significant deformation without rupture. The braid reinforced specimens showed the highest peak load. The addition of the unidirectional to the matrix resulted in an average strain of 0.06 mm/mm which is 50% greater than the capacity of the unreinforced matrix, whereas the addition of the braid and leno-weave resulted in increases of 119 and 126%, respectively, emphasizing the higher capacity of both the UHM polyethylene fibers and the architectures to hold together without rupture under flexural loading. The addition of the fiber reinforcement substantially increases the level of strain energy in the specimens with the maximum being attained in the braid reinforced specimens with a 433% increase in energy absorption capability above the unreinforced case. The minimum scatter and highest consistency in response is seen in the leno-weave reinforced specimens e to the details of the architecture which restrict fabric shearing and movement ring placement.

Significance

It is crucial that the appropriate selection of fiber architectures be made not just from a perspective of highest strength, but overall damage tolerance and energy absorption. Differences in weaves and architectures can result in substantially different performance and appropriate selection can mitigate premature and catastrophic failure. The study provides details of materials level response characteristics which are useful in selection of the fiber reinforcement based on specifics of application.

Keywords: Fiber reinforcement; Dental composite; Flexure; Damage tolerance; Architecture; Unidirectional; Braid; Leno-weave

Article Outline

1. Introction
2. Materials and methods
3. Results
4. Discussion
5. Summary
References

1. Introction

A range of fillers in particulate form have conventionally been used to improve performance characteristics, such as strength, toughness and wear resistance, Although the addition of fillers and recent changes in composition of resin composites have been noted to provide enhanced wear resistance [1] and [2], conventional filler based systems are still brittle as compared to metals. Sakaguchi et al. [3] reported that these were prone to early fracture with crack propagation rates in excess of those seen in porcelain. This is of concern since clinical observations have demonstrated that under forces generated ring mastication the inner faces of restorations can be subject to high tensile stresses which cause premature fracture initiation and failure [4]. In recent years, fiber reinforcements in the form of ribbons have been introced to address these deficiencies [5]. By etching and bonding to tooth structure with composite resins embedded with woven fibers adapted to the contours of teeth periodontal splints, endodontic posts, anterior and posterior fixed partial dentures, orthodontic retainers and reinforcement of single tooth restorations can be accomplished. While the science of fiber-reinforced polymer composites is well established, the application of these materials in dental applications is still new and aspects related to material characterization, cure kinetics and even placement of reinforcement are still not widely understood.

Due to the nature of filled polymer and ceramic systems that have been used conventionally, most material level tests designed and used extensively, for the characterization of dental materials, emphasize the brittle nature of materials response. In many cases the tests and the interpretation of results, are not suited to the class of fiber-reinforced polymeric composites, wherein aspects, such as fiber orientation, placement of fabric and even scale effects are extremely important. The difference in characteristics and the need to develop a fundamental understanding of response of continuous fiber and fabric, reinforced dental composites has recently been emphasized both through laboratory and clinical studies. Recent studies have addressed critical aspects, such as effects of fabric layer thickness ratios and configurations [6], fiber position and orientation [7] and even test specimen size [8]. However, the selection and use of continuous reinforcement is largely on an ad hoc basis, with diverse claims being made by manufacturers, without a thorough understanding of the materials based performance demands for the material by the specifics of an application (for example, the fabric architecture required for optimized performance of a post are very different from those for a bridge) or details of response characteristics at levels beyond those of mere 「strength」 and 「molus」. Further, each fabric is known to respond in different manner to manipulation and drape (i.e. conformance) to changes in substrate configuration [9]. The architecture of the fabrics permits movement of fibers or constraint thereof and even shearing of the structure, to different extents. Weave patterns have also been noted to be important in the selection of composite materials for dental applications based on the specifics of application [10]. Thus, clinically, when each of the different fabric configurations is used to reinforce dental composites, there are manipulation changes that occur to some of the fabric materials. For the biaxially braided material, the fiber orientation can change after cutting and embedment in the composite when adapting to tooth contours. The fibers in the ribbon spread out and separate from each other and become more oriented in a direction transverse to the longitudinal axis of the ribbon. When the leno-weave is cut and embedded in dental composites, the fiber yarns maintain their orientation and do not separate from each other when closely adapted to the contours of teeth. However, e to the orthogonal structure gaps can appear within the architecture providing local areas unreinforced with fiber reinforcement. The unidirectional glass fiber material does not closely adapt to the contours of teeth e to the rigidity of the fibers. It is difficult to manipulate the fibrous material which leaves the final composite material thicker; further manipulation causes glass fiber separation with some visible fractures of the fibers themselves.

The aim of this study is to experimentally assess the flexural response of three commercial fiber/fabric reinforcement systems available for dental use and to compare performance based on different characteristics and to elucidate differences based on details of fabric architecture and fiber type.

2. Materials and methods

Three different fabric-reinforcing procts, all in ribbon form, were used in this investigation. The first is a 3 mm wide unidirectional E-glass prepreg structure with no transverse reinforcement (Splint-It, Jeneric/Petron Inc.1) designated as set A, whereas the other two are formed of ultra-high molecular weight polyethylene fibers in the form of a 4 mm wide biaxial braid (Connect, Kerr), designated as set B and a 3 mm wide Leno-weave (Ribbond, WA), designated as set C. The first is a pure unidirectional which intrinsically gives the highest efficiency of reinforcement in the longitudinal direction with resin dominated response in the transverse direction. The second is a biaxial braid without axial fibers, which provides very good conformability and structure through the two sets of yarns forming a symmetrical array with the yarns oriented at a fixed angle from the braid axis. The third architecture has warp yarns crossed pair wise in a figure of eight pattern as filling yarns providing an open weave effect for controlled yarn slippage and good stability.

Multiple specimens of the fabrics were carefully measured and weighed and the average basis weight of the biaxial braid was determined to be 1.03 × 10−4 g/mm2 whereas that for the leno-weave was 1.42 × 10−4 g/mm2. It was noted that the unidirectional had an aerial weight of 2.2 times that of the other two. Rectangular test bars of size 2 mm × 2 mm × 48 mm were constructed from layered placement of a flowable composite resin (Virtuoso FloRestore, Demat) in polysiloxane molds, with glass slides held on top with rubber bands and light cured for 60 s using a Kulzer UniXS laboratory polymerization lamp. In the case of sets B and C the fabric was first wetted and then placed on the first layer of the flowable composite resin such that the fiber reinforcement was placed between 0.25 and 0.5 mm from the bottom surface (which would be used as the tensile surface in flexural testing). The addition of higher molus material at or near the tensile surface is known from elementary mechanics of materials to increase flexural performance and has been verified for dental composite materials by Ellakwa et al. [11] and [12]. Care was taken to maintain alignment of the fibers and fabric structure and not cause wrinkling or lateral movement which would affect overall performance characteristics. The fabric reinforced specimens had only a single layer of reinforcement near the bottom surface with the rest of the specimen having no fiber reinforcement. This general configuration for flexural specimens has been used previously by Kanie et al. [13]. In the current investigation, fiber weight fraction in the single layer was between 37 and 42% but is significantly lower if determined on the basis of the full thickness of the overall specimen. Unreinforced bars of the resin were also fabricated the same way for comparison and were designated as set D.

Eight specimens (n = 8) from each set were tested in three-point flexure using a span of 16 mm which provides a span to depth (l/d) ratio of 16, which is recommended by ASTM D 790-03 [14]. It is noted that flexural characteristics can be substantially affected by choice of the l/d ratio which intrinsically sets the balance between shear and bending moment, with shear dominating on shorter spans. Load was introced through a rounded crosshead indenter placed in two positions—parallel to the test specimen span (P1) and perpendicular to the test specimen span (P2). The load head indenter was of 4 mm total length. This was done to assess effects of load introction since ribbon architecture had fibers at different orientations. Tests were concted at a displacement rate of 1 mm/min and a minimum of eight tests were concted for each set. Loading was continued till either the specimen showed catastrophic rupture or the specimen attained a negative slope of load versus displacement with the load drop continuing slowly past peak to below 85% of the peak load. This level was chosen to exceed the 0.05 mm/mm strain limitation of apparent failure recommended by ASTM D790-03 [14] so as to enable an assessment of ctility of the specimens. Specimens were carefully examined for cracking, crazing and other damage.

The flexure strength was determined as

Click to view the MathML source (1)

where P is the applied load (or peak load if rupture did not occur), L the span length between supports and b and d are the width and thickness of the specimens, respectively.

While the tangent molus of elasticity is often used to determine the molus of specimens, by drawing a tangent to the steepest initial straight-line portion of the load-deflection curve to measure the slope, m, which is then used as

Click to view the MathML source (2)

in the current case a majority of the specimens show significant changes in slopes very early in the response curve indicating microcracking and non-linearity. Since these occur fairly early the molus determined from the initial tangent has significant statistical variation. In order to determine a more consistent measure of molus the secant molus of elasticity as defined in ASTM D790-03 [14] is used herein, with the secant being drawn between the origin and the point of maximum load to determine the slope m, which is then used in Eq. (2). This also has the advantage of providing a characteristic that incorporates the deformation capability, thereby differentiating between specimens that reach a maximum load at low deformation (such as, the unreinforced composite and the unidirectional reinforced composite) and those that show significant deformation prior to attainment of peak load (such as, the specimens reinforced with the braid and leno-weave).

The matrix material is generically more brittle than the fiber and usually has a lower ultimate strain. Thus, as the specimen bends the matrix is likely to develop a series of cracks with the initiation and propagation of cracks depending not just on the type and positioning of the reinforcement, but also on the strain capacity of the neat resin areas. It is thus of use to compute the strain in the composite under flexural load and this can be determined as

Click to view the MathML source (3)

where D is the midspan displacement.

The toughness of a material can be related to both its ctility and its ultimate strength. This is an important performance characteristic and is often represented in terms of strain energy, U, which represents the work done to cause a deformation. This is essentially the area under the load-deformation curve and can be calculated as

Click to view the MathML source (4)

where P is the applied load and x is the deformation. In the case of the present investigation, two levels of strain energy are calculated to enable an assessment of the two response types. In the first, strain energy is computed to the deformation level corresponding to peak load (which is also the fracture load for sets A and D). In the case of specimens that show significant inelastic deformation (sets B and C) strain energy is also computed till a point corresponding to a deformation of 11.5 mm at which point the load shows a 15% drop from the peak. Post-peak response in flexural has earlier been reported by Alander et al. [8].

3. Results

The application of flexural loading was seen to result in two different macroscopic forms of response. In the case of specimens from sets A and D (reinforced with a unidirectional fabric and unreinforced) failure was catastrophic, in brittle fashion, at peak load, whereas in the case of specimens from sets B and C the attainment of peak load was followed by a very slow decrease in load with increasing displacement, representative of inelastic or plastic, deformation. Typical response curves are shown in Fig. 1 as an example.

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Fig. 1. Typical flexural response.

The variation in flexural strength (plotted here in terms of stress at peak load) with type of specimen and load introction method is shown in Fig. 2. The highest strength was achieved by specimens with the braided fabric wherein on average a 125% increase over the unreinforced specimens was attained. Statistical analysis with ANOVA and Tukey's post hoc test revealed that method of load introction did not affect the results and that further there were no significant differences in overall peak strength results between sets A and B (specimens containing the unidirectional and braided fabrics). Significant differences (p < 0.003) were noted between sets B and C. It is, however, noted that in sets B and C, failure did not occur at the peak load, with load slowly decreasing with increase in midpoint deflection. A comparison of flexural stresses for these systems at peak load and load corresponding to a deflection of 11.5 mm is shown in Fig. 3. As can be seen the two systems show significant inelastic deformation with drops of only 12.8, 12.1, 11.7 and 9.5% from the peak, emphasizing the stable, ctile and non-catastrophic, post-peak response in these systems.

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Fig. 2. Flexural strength at peak load.

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Fig. 3. Comparison of flexural stresses in specimens having non-catastrophic failure modes.

A comparison of secant molus (measured to the peak load) for the different sets is shown in Fig. 4. As can be seen, with the exception of the unidirectional system, the apparent moli were lower than that of the unreinforced specimens. It is also noted that although the Tukey post hoc tests do not show a significant difference e to orientation of load indenter, the level for the unidirectionals is only 0.1022 compared to 1 for the others. Removal of a single outlier from P1 results in p < 0.007 indicating a strong effect of orientation of the indenter with the secant molus being 17.7% lower with the indenter placed parallel to the fibers, which results in splitting between fibers and uneven fracture with less pullout.

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Fig. 4. Comparison of secant moli under flexural loading.

As was noted previously, both the unreinforced samples (set D) and the unidirectional prepreg reinforced specimens (set A) failed in catastrophic fashion at deformation levels significantly less than those at which the other two sets reached the inelastic peak. Since sets B and C did not fracture but showed large deformation with some partial depth cracking through the matrix it is important to be able to compare the levels of strain attained on the tension face using Eq. (3). This comparison is shown in Fig. 5 at the level of peak load (which is the fracture/failure load for sets A and D). While the addition of the unidirectional to the matrix resulted in an average strain of 0.06 mm/mm which is 50% greater than the capacity of the unreinforced matrix, the addition of the braid and leno-weave resulted in increases of 119 and 126%, respectively, emphasizing the higher capacity of both the UHMW polyethylene fibers and the architectures to hold together without rupture under flexural loading. It should be noted, as a reference, that the strain at the point at which the tests on sets B and C were stopped, at a midpoint deflection of 11.5 mm, was 0.135 mm/mm, which represents a 233% increase over the level attained by the unreinforced matrix. The us