Britain and the League of Nations Before WWII

Britain and the League of Nations Before WWII Why Was Britain So Ill-Prepared for War in 1939? Consequences of WWI The representatives of the states that met at Versailles in the first half of 1919 were confronted by a world in deep turmoil. The war was over but it appeared that a significant threat still remained in the form of the rapid spread of bolshevism. Right wing governments were springing up in Eastern Europe, and the victors of the war were worried.[1] A reaction to this, and as something of a punishment to Germany, was the redrawing of borders throughout Central and Eastern Europe. Huge swathes of various nations ware effectively removed and annexed by a neighbouring state. Germany’s eastern frontier, for example, was moved far to the west of its previous position, removing part of Silicia, West Prussia and Posses from German control and given to neighbouring states. Germany was not the only state to suffer, however, Russia lost vast areas of land in the west and Finland, Latvia, Estonia and Lithuania became independent states.[2] This realignment of Europe was widely unpopular and provided some of the seeds for future conflict, it was only achievable through the new instrument if international diplomacy, the League of Nations. The mandate of this new league was to maintain peace in Europe. Refusal to abide by the dictates of the league would result in economic or military sanctions; the main problem was that the league did not directly command any troops and its actions required the unanimous consent of all members. Great Britain, after the deprivations of the First World War, seemed little interested in getting too heavily involved in the affairs of its European allies and hoped the League would essentially remove that responsibility. Britain showed such revulsion at the prospect of another (or further) was that in 1919 Winston Churchill, former First Lord of the Admiralty, persuaded the British government to adopt a rule whereby â€Å"for the purpose of framing the (defence) estimates, (it should be assumed) that at any given date there will be no major war for 10 years.†[3] This so called ten year rule was officially renewed every year until 1932, and even then Britain took now significant steps towards rearmament until 1937. This ten year rule meant that if war was to break out in Europe again, Britain was certain to be caught unprepared. Hitler Adolf Hitler came to power in Germany in 1933 on the back of deep resentment of the treatment of Germany by the western allies at the end of the First World War. In 1934 he had been shown a demonstration of the potential of the new tank arm that was being developed in secret by Guderian,[4] and by the following year three panzer divisions were under construction.[5] By 1935 his power base was strong enough for him to renounce the clauses of the treaty of Versailles that limited the German army to 100,000 men; he reintroduced conscription and decreed the creation of the Luftwaffe, banned by Versailles.[6] By 1936 Hitler has negotiates a treaty with Britain that allowed him to build U-boats and he sent troops to unilaterally occupy the demilitarised Rhineland. In 1937 the new German army had 37 infantry divisions and three panzer divisions, in comparison to the seven allowed by Versailles, a total strength of three million men, the following year saw the strength of the newly formed Lu ftwaffe at 3350 (zero in 1932).[7] While obvious rearmament was underway in Germany, and the French were building the Maginot line (clearly expecting and preparing for ‘static’ trench warfare) along the border with Germany, the British steadfastly refused to re-arm, believing in the principle of the ten year rule. The economic situation in Great Britain was poor after WWI, unemployment was high and the economy generally was performing very poorly indeed. This situation was not at all aided by the great depression that developed with stunning rapidity in the United States. This can be juxtaposed with the booming German economy where unemployment had fallen from five and a half million to less than one million under Hitler,[8] it is perhaps not too surprising that Britain felt ill equipped financially or perhaps emotionally after the deprivations of trench warfare) to rearm or resist German expansion until it was too late. Failure of the League of Nations The great hope of the British (and to a very large extent of the other western powers) was that any potential for future conflict in Europe would be obviated by the League of Nations; this was its very reason for existing in the first place. A series of devastating setbacks for the League essentially exposed its impotence. Mussolini’s invasion of Abasynnia in 1935 (a member of the league), was met with economic sanctions at the behest of the British, but this only drove the Italians into Hitler’s arms (a long time admirer of Mussolini). The next crisis for, and failure of, the League came the following year: misrule in Spain led to an uprising by General Franco. The government were supported by Russian troops and Franco by Italians. Taking this opportunity Hitler entered into an anti-communist treaty with the government of Japan, and as it became apparent that Franco was winning the civil war, and while the attentions of the world were elsewhere, he annexed Austria;[9] two weeks later the Sudetenland. This series of seriously mishandled crises demonstrated that the League of Nations was totally ill equipped to perform a peace keeping role in Europe and it disintegrated. Britain’s (and Churchill’s faith in the League and the ten year plan had been seriously flawed). Britain Re-arms – Treasury Resists The main consequence for the British and the French of the events of 1935-6 was a sudden realisation that rearmament was required, and quickly. The situations in Abasynnia, Spain and Germany clearly demonstrated the, at best, inability, and at worst incompetence of the League of Nations. The only possible conclusion for the British by the mid 1930’s was that the only way to deter aggression, and future war, was with a significant military presence. Baldwin had been elected to office in Britain the back of a promise to rearm. British public opinion, then, was in favour of rearmament, but political leaders remained strangely opposed. By 1936 the military budget was increased to  £136 million, but this was still only half of that of Germany, and they newly created post of Minister of Public Defence was given to the weak Sir Thomas Inskip rather than someone like Churchill.[10] This new post had been described simply as a â€Å"treasury break on the demands of the service†,[11] which is to say a means of keeping down military expenditure. As Chancellor of the Exchequer, Chamberlain firmly believed that the economy was the fourth branch of the armed services. He believed that economic stability was of prime importance and that it could not be put at risk in order to rearm the country. He believed that economic strength would act as a deterrent to any potential enemy and that financial strength could enable the nation to purchase any military equipment it may need as and when required, thus permanent rearmament was not deemed a priority.[12] Chamberlain in fact argued that the economy simply could not bear the strain of rearmament. His military logic was seriously and obviously flawed, be argued that id Germany made war in the east, this was simply too far away for the British to do anything about it, and if the invaded France or the Low Countries, the British would not be able to react fast enough, therefore a large standing army was not necessary.[13] There were also serious strategic discussions in Britain at the time; should rearmament be based on land forces or on the navy and air force. Some believed in the magical power of the newly developing air forces. General John Burnett-Stuart[14] argued that an appropriately large and well equipped air force could far better perform the role of the expeditionary force in protecting the Low Countries and indeed in winning a war with far less risk of loss of life.[15] Britain, then, was in serious disarray as to what strategy to pursue, and was not given the financial backing to pursue any strategy fully. Strategy Blitzkrieg The question may presuppose that Britain was ill prepared in simply practical terms, be they military or economic, but there is far more to the question that this. Britain, and indeed every one else in the world, was seriously ill prepared for war in 1939 in terms of strategic thinking as well. It has often been noted that large wars begin with the strategy of the last major war; this was not the case in World War II. World War I had effectively began with Napoleonic tactics that developed into static, and devastating, trench warfare. The building of the Maginot line by the French is a strong indication that a future was (i.e. WWII) would again be a static war in the mould of trench warfare.[16] The Germans, however, had other ideas. Heinz Guderian had fought in WWI and seen the stupidity of trench warfare, and the potential of the tank if properly utilised. During the inter war years he developed a strategy of mobile warfare,[17] later to become infamously known as blitzkrieg,[18] lightening war. He came to believe, and persuaded Hitler of the same, (as noted briefly above) that the panzer, utilised in massed formations, could act as a hammer and smash a hole through the enemies’ defensive line. Following this initial action (to be preceded by artillery bombardments and air strikes) the fast moving panzer divisions,[19] along with mechanised infantry units,[20] could stream through this gap in the line and drive quickly deep into enemy territory, seriously disrupting their lines of communication and supply. These units could then be used to encircle slow moving (or static) enemy infantry. Conclusion This new strategy, new philosophy, was the second strand to Britain’s unpreparedness (and indeed everyone else’s too). For one of the few times in history, Germany entered the war with an entirely new philosophy, one for which their entire armed forced had been forged and developed to utilise with devastating effect. The British, French, Russians etc. were utterly unprepared for an offensive of the scale that Hitler launched, or for the tactics that were being employed. In every campaign, highlighted spectacularly in Poland, the Low Countries and France, the Wehrmacht were capable of moving far faster than the allies could counter. I have tried to argue throughout this brief essay that Britain was not the only nation to be ill prepared for war with Germany in 1939. The lack of preparation was partly due to poorly placed faith in the League of Nations and in the ten year plan, but also on an unwillingness to properly invest in the armed forces until it was too late to deter war. The allies were also utterly unprepared for the new kind of warfare brought by the Germans and it is this final point that leads to the conclusion that even if funding had been available and rearmament had taken place much earlier, would it have made a difference given the vastly superior strategy and technology employed by the Wehrmacht. Bibliography C. Barnett (ed.), Hitler’s Generals (London 1989) J. F. C. Fuller, Decisive Battles of the Western World and their Influence Upon History: vol III (London 1956) H. Guderian, Achtung-Panzer (Berlin 1937) D. Kagan, On the Origins of War (London 1995) J. Keegan, A History of Warfare (London 1993) K. Macksey, Guderian: Panzer General (London 1975) C. Messenger, The Art of Blitzkrieg (London 1976) A. J. P. Taylor, English History: 1914-1945 (Oxford 1965) Footnotes [1] Kagan, 1995, 285. [2] Kagan, 1995, 287. [3] Keegan, 1993, 366. [4] More on Guderian later. [5] Barnett, 1989, 444-5 [6] Keegan, 1993, 367. [7] Keegan, 1993, 368. [8] Fuller, 1956, 369. [9] Fuller, 1956, 371. [10] Kagan, 1995, 367. [11] Taylor, 1965, 390. [12] Kagan, 1995, 370-1. [13] Kagan, 1995, 371. [14] Kagan, 1995, 3. [15] This is an idea that seems somewhat ahead of its time, the first time this occurred (an air force essentially winning a war) was the first Gulf War of 1991. [16] Guderian, 1937, 36-38. [17] Macksay, 1965, 57-79. [18] Messenger, 1976. [19] Guderian, 1937, 167-170. [20] Guderian, 1937, 171-173.

Defining an Individual Essay -- Expository Definition Essays Papers In

Defining an Individual What is an individual? How can one become an individual? Is it even possible to become an individual in society? Can we successfully distinguish ourselves from the majority to make our own decisions? How does your family affect your personality and every day decision making: your ethics and morals? How does your childhood affect you today? How does it affect our subconscious-something we can not control and we do not have access to? Is it possible to go back in time and completely erase everything we have been taught through years of brainwashing and manipulation, not only from the system that we are brought up in but also the family and lifestyles that are now part of us? The term "individual" as seen from the Webster's New Universal Unabridged Dictionary states as follows: Individual- 1. Originally, not divisible, not separate. 2. Existing as a single, separate thing or being; single, separate, particular. 3. Of, for or by a single person or thing. 4. Relating to or characteristic of a single person or thing. 5. Distinguished from others by special characteristics, of a particular or striking character, as an individual style. People claim to be individuals every day. Everywhere we go " individuals" follow us. They are on television, in movies, newspapers, magazines, they even live with us, in our homes. Everyone has a deep desire to stand apart. " Pave your own way." A classic example of individualistic patterns set from a society that at the same time pushes you away from that idea. In a very literal sense to be an individual you need to live every moment of your existence in your very own personal way. Not hindered by the outside and inside persuasions, yo... ...hy people rebel against the idea that it is impossible to be an individual. In conclusion, it is not the fact that we are all individuals separate from each other or society. The fact remains that it is impossible to delve into your own subconscious and erase everything we have been taught and brainwashed. The important idea to remember is the relationship we have with our society and each other that truly is unique. That is where the individuality comes into play. Trying to separate ourselves and prove ourselves different is only going to frustrate even the most intelligent of characters. The world that we live in, no matter how incredibly large it may seem, is made for each and everyone of us. What we do with what society has set in us and what we do with all that we have been taught is the true answer in the ultimate question: Individuality- Is it possible?

Pentecostal History Essay -- Church History

To know the history of the Pentecostal movement, one needs to know what they believe. Pentecostalism is a movement within Christianity that places special emphasis on a direct personal experience of God through the baptism in the Holy Spirit. During Pentecost, the Holy Spirit fell upon those in the upper room. Acts 2:1-4 says, â€Å"When the day of Pentecost came, they were all together in one place. 2 Suddenly a sound like the blowing of a violent wind came from heaven and filled the whole house where they were sitting. 3 They saw what seemed to be tongues of fire that separated and came to rest on each of them. 4 All of them were filled with the Holy Spirit and began to speak in other tongues[ as the Spirit enabled them.† (1,3) The Pentecostal movement started in the late 19th century in revival movements in Great Britain and in the United States of America. Within this movement more attention was placed on the person and the work of the Holy Spirit. Some people felt that the church was missing the power and authority of the church they read about in the bible. We will look at the Pentecostal movement from the past and look at it all the way up through to today. (1) The earliest date given for the beginning of the Pentecostal movement is January 1, 1901. A man by the name of Charles Parham began teaching that the act of speaking in tongues was the biblical evidence that someone was filled with the Holy Spirit. He started teaching this at Bethel Bible College in Topeka, Kansas. Over time Charles Parham moved to Texas to teach. While Charles spoke in Texas, William J. Seymour was attending. William J. Seymour traveled to Los Angeles where he led the Azusa Street Revivals in 1906. The beginning of the w... ...ecostals. It is important to know where we came from in order to know where we are going. The future is bright for the Assemblies of God if they just rely on God and the power of the Holy Spirit. Works Cited 1. Wacker, Grant. Heaven Below: Early Pentecostals and American Culture. Cambridge, Massachusetts: Harvard University Press, 2001. 2. Miller, Donald E. and Tetsunao Yamamori. Global Pentecostalism: The New Face of Christian Social Engagement. Berkeley, California: University of California Press, 2007. 3. Hollenweger, Walter. Pentecostalism : Origins and Developments Worldwide. Peabody, Massachusetts: Hendrickson Publishers, 1997 4. Burgess. Encyclopedia of Pentecostal and Charismatic Christianity 5. Blumhofer, Edith L. Restoring the Faith: The Assemblies of God, Pentecostalism, and American Culture, 1993 6. www.ag.org

Computer Piracy in The Music Industry Essay -- mp3 file sharing music

Computer Piracy (The Music Industry) The music industry has had problems with computer piracy for many years now. There have been many programs devoted to giving out free music. Many of these programs are well know, but still very hard to stop. Napster, Kazaa, and the newest program, myTunes Redux are the most popular programs for music sharing. This essay will explain all about these main programs which allow free music to be shared all over the world. File-sharing became big right around the time the Napster file-sharing program came out. Napster is an online service which was invented by an 18-year-old college student that allows a user to see song files residing on the hard drives of other users, and to download copies of any of those songs. (DLC.org) Napster started off at a slow pace, becoming popular at colleges and then it just exploded. Everyone was using this program within a year of its creation. (DLC.org) However, it eventually got busted and the idea of free music was shutdown, or so the music industry thought. Napster continues to be around today, but with a legal persona. After Napster was told to stop there illegal program there were many other programs in the making. Programs even more advanced then Napster. The next program to come along which caused a big stir was a program known as Kazaa. Kazaa took file sharing to the next level by also allowing movie and picture files to be shared rather than just music files. The Kazaa protocol is the brainchild of the Scandinavians Niklas Zennstrà ¶m and Janus Friis and was introduced in March 2001 by their Dutch company Consumer Empowerment. (Wikipedia.org) Like the creators of Napster, Kazaa's owners have been taken to court by m... ...l and is the biggest file sharing program since Napster and Kazaa. There will most likely be a final resolution to this new program by next year. Basically, file sharing programs will always be around. They even are able to avoid law suits by explaining that it is the user who is breaking the law. The world of the music industry needs to understand that there is nothing they can do to stop it. All they can do is try to find ways to work around it. Besides, if someone really enjoys a band, they would go out and support them by buying their cd. In the end, file sharing is part of the world around us and will remain here for many years to come. Works Cited http://www.dlc.org/print.cfm?contentid=646 http://en.wikipedia.org/wiki/Kazaa http://news.com.com/MyTunes+returns+for+iTunes+song+sharing/2100-1027_3- 5349272.html

research :: essays research papers

History of Computer: -important people Allen, Paul G. - Co-founder of Microsoft Corp. Allen left the company in 1985 but remained on the board of directors and as founded or financially supported several innovative computer ventures, including Asymetrix and Starware Corp. He is involved with a variety of other projects, including a Jimi Hendrix Museum in Seattle. Amdahl, Gene M - South Dakota native who helped design the IBM 704, the S/360 series. He was the founder of the Amdahl Corp. Andreessen, Marc - Co-founder (at the age of 22) of Netscape Communications, along with Silicon Graphics founder James H. Clark. Before Andreessen graduated from the University of Illinois in Champaign, he had created the NCSA Mosaic prototype with a team of students and staff at the university's National Center for Supercomputing Applications. Babbage, Charles (1791-1871) - Eccentric, English mathematician who is considered to have conceptualized the modern computer a century before technology let it be built. He conceptualized the Difference Engine, a machine that would have computed lengthy scientific tables, but money, labor, and health problems prevented its completion. The Analytical Engine, a more ambitious plan, would have done a wide range of calculating tasks. With it, Babbage recognized the need for an input device, memory, a central processing unit, and an output device, and for this he is known as the Father of Computing. Backus, John W. - Mathematician from Philadelphia who headed the research team at IBM that created FORTRAN, the first machine independent programming language. -important devices/developments Floppy Drive - The floppy drive is always called "Drive A:". A floppy disk can hold 1.5 megabytes of data. That's about 1,500,000 characters or letters (or about 300,000 words). That's more than enough space for the text of a large book. Pictures, however, take up a great deal of room. You could only fit a small number of good-quality pictures (or graphics) on a floppy disk. Hard drive - This drive uses disks that are made of aluminium or glass (and therefore 'hard'). Each disk can store much more information than either a floppy or CD-ROM. Sometimes, there may be several disks in a hard drive. However, the disks in a normal hard drive can not be removed or replaced. Today, hard drives are measured in gigabytes. That's one thousand million bytes. 1 gigabyte is about 11/3 CD-ROM disks. Motherboard - Everything inside the computer is connected to a circuit board called the 'motherboard'.

Culture Change in Korean Women Essay

Sweeping cultural change rarely comes rapidly. Even in places where the constitution of the nation would guarantee equality of citizens, achieving true equality can be an agonizingly slow process. In the United States, for example, a fledgling women’s suffrage movement was present as early as the middle 1700s. The right to vote, however, would not be realized until 1920, over a hundred and fifty years later. Korea is a divided nation even more steeped in cultural tradition. Although there are some subtle differences, depending on region and class, Koreans still live in a regimented, patriarchal society. Globalization can result in a more equal society. The world is more economically interrelated than ever. The power of tradition is strong, however. Economic change has moved much more rapidly than social change within Korea. Generally speaking, cultural change within large, modern cities is occurring at a modest pace. In most rural areas, there has been little, if any, change in recent centuries. Surprisingly, emigration to the United States has not rapidly increased social change among the Korean community, evidencing the strength of cultural ties. Social change in Korea will continue to make uneven progress in the future because access to education varies widely among regions and classes. In the late 20th century there has been a dramatic shift in the center of women’s rights activity. Areas of the country that have greater interrelation have made greater strides toward the full liberation of women. Early in the 20th century, northern Korean cities saw the first cautious steps toward the empowerment of women. The communist regime has stalled cultural progress, not only for women but for everyone. Today, the center of cultural change is located in the South. Regardless of the location, the nature of the Korean character indicates that cultural change, especially for women, will always move slower than economic change. The Patriarchal Society The centuries –old influence of Confucianism in Korea has resulted in a class-conscious, patriarchal society. The influence of Japanese invaders in the mid-20th century only served to reinforce that reality. The Confucianism practiced in Korea mandated strict roles for men and women. Women were relegated to house work and discouraged from seeking any marketable education. Besides the influence of tradition, critics of increased liberty and opportunity have used a similar tactic to those who resisted this process in other countries. They claim that liberation from traditional roles for women will destroy the family structure. Similar arguments were made in relation to women’s suffrage in the United States. It is an argument that carries weight, particularly in a nation with such a deep paternalistic. background as Korea. Even in modern South Korea, the influence is still apparent. † Women still believe that they should be good housewives and mothers. There is some change but it is very, very slow† (Palley, 1990). Geographical and Class Differences The most obvious regional differences in culture come between the economically advanced state of South Korea and the economically stagnant, communist North Korea. The advanced industrial cities in the south, such as Seoul, have seen a liberalization of society, even if it lags behind the pace of economic change. The industrialization and modernization of South Korea has also resulted in the rise of a women’s movement, particularly in the larger cities. Early in the 20th century, the education of women was much more prevalent in the northern area of Korea, particularly Pyongyang. There were two factors present there which correlated closely with the education of women. The elite classes were concentrated in northern areas at that time, and; there was also a strong presence of western missionaries there. Education for women was typically restricted to the upper classes. Consequently, professions in which women could participate were severely limited. In the 1930s, only three out of 100,000 college-age Korean women took part in higher education Being born into a higher class, however, did not necessarily increase freedom. While women from the elite class have always been more likely to receive education, that education did not necessarily flow into a career. In fact, as Jihang Park reports, â€Å"†¦the higher the woman’s status, the more severe her seclusion† (1990). Jihang Park writes that, â€Å"In Korea, education was the primary focus of the women’s movement and remained so until 1945 (1990). A college for women has been in operation since the early 20th century, but the subjects available for study were limited in the early decades to preparing women for homemaking. The first generation of college educated women in Korea were not effective advocates for increased cultural change. Because they were primarily from the elite classes, they were not especially career-driven. For many, education was mainly a means for attracting a better husband. Even where some progress toward equality is being made, the process is slow and incomplete. â€Å"Opportunities for professional mobility are very limited, and on average in 1988 women earned approximately 45% that of men† (Palley, 1990). A number of women’s rights organizations have emerged in the south, but their effect on issues such as these have been minimal. Korean Immigrants A superficial cultural analysis of United States immigrants might conclude that exposure to economic and social liberty would substantially change the culture of immigrants and their descendants. Korean immigrants are somewhat unique, however, Whereas other immigrant groups are highly diverse in language and cultural practices, Korean immigrants tend to form a more homogenous group. Within that group, exposure to the outside culture remains somewhat limited and the cultural traditions brought from Korea remain strong. Many Koreans work in businesses tailored mainly to serve their own community. Many Korean immigrants, male and female, â€Å"have little opportunity to learn American customs, including a more egalitarian gender role orientation† (Pyong Gap Min, 2001). Economic realities have dictated some changes. An increasing number of Korean women are finding it necessary to work outside the home. Many wives work along side their husbands. The participation of married Korean women in the American labor force has increased from about 17% in 1980 to 25% in 1990 (Min, 2001). As it did with American women in the mid 20th century, working outside the home is empowering women to take a more active role in determining their own lives. Korean men grudgingly accept that women are entering the workforce, but still feel driven to maintain traditions at home. The result is a many marriages of Korean-Americans are experiencing strain. At the same time, cultural tradition stresses the importance of marriage. During the first half of the 20th century, more than 99% of Korean women were married by the age of forty-five (Jihang Park, 1990). Analysis and Conclusion There are some forces within Korea which are advocating social changes on behalf of women. Eventually, a more equal Korea will emerge. The question is whether it will take tens of years or hundreds of years. Those forces within Korea must battle against hundreds of years of deeply ingrained cultural tradition. Societal change at a significant level is often initiated by the middle class. The gradually growing workforce of Korean women will need to develop effective leaders in future years to move the process toward equality forward (Palley, 1990). In the past, the most influential forces for women’s rights have been external. Missionaries, in particular have been relatively effective in advocating education and basic human rights for women. It will take a larger force, though, to foster fundamental and lasting change for the lives of women in Korea. Fundamental social change is often economically-driven. Globalization is a seemingly irresistible economic force in the 21st century. Its focus on technology, education and interrelation with the world will force countries to either recognize the economic potential of women or risk being left behind. The pace of cultural change varies, and will continue to vary, depending on a number of factors. Some types of change are more easily accepted than others. For example, Korean-American men have accepted the necessity of their wives working but many do not accept that this can mean an alteration of marriage roles. Korean women in North Korea, South Korea and America are working in greater numbers than ever before. In a few cases, this has given them greater access to education and the political system. In most cases, however, it has not. Sources Min, Pyong Gap. (2001). â€Å"Changes in Korean Immigrants’ Gender Role and Social Status, and Their Marital Conflicts. † Sociological Forum. Vol. 16, No. 2 (Jun. ), pp. 301-320. Min, Pyong Gap. (2003). â€Å"Korean â€Å"Comfort Women†: The Intersection of Colonial Power, Gender and Class. † Gender and Society. Vol. 17, No. 6 (Dec. ), pp. 938-957. Palley, Marian Lief. (1990). â€Å"Women’s Status in South Korea: Tradition and Change. † Asian Survey. Vol. 30, No. 12 (Dec. ), pp. 1136-1153. Park, Jihang. (1990). â€Å"Trailblazers in a Traditional World: Korea’s First Women College Graduates, 1910-45. † Social Science History. Vol. 14, No. 4 (Winter), pp. 533-558.

Experimental Estimating Deflection of a Simple Beam Bridge Model Using Grating Eddy Current Sensors

Abstract: A novel three-point method using a grating eddy current absolute position sensor (GECS) for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring. Keywords: three-point method; deflection estimation; relative deflection; absolute deflection; grating eddy current sensor (GECS) OPEN ACCESS Sensors 2012, 12 9988 1. Introduction. After a bridge is put into use, gradual deterioration is inevitable because of loading, temperature changes or other environmental factors. In order to guarantee the safety and durability of those bridges which are expensive and closely related with people’s livelihood, long-term and continuous structural health monitoring is an essential part of the maintenance management. Among the various structural performance evaluations, vertical deflection is an important parameter that can directly and effectively indicate a bridge ’s behavior. In terms of instrumentation for deflection estimation, there are contact and non-contact deflection estimation methods. Traditional displacement sensors such as mechanical dial gauges or linear variable differential transducers (LVDTs) are used in contact measurement, through which static or real-time displacement values can be obtained directly or fed into a computer for processing and displaying via a data cable. This method, however, requires access under the bridge and installation of a temporary supporting system to mount sensors, which is time consuming and not very efficienct. In addition, it might even be unavailable when bridges are over rivers, highways or have high clearance. Another contact sensor is the fiber optic Bragg-grating (FBG) sensor through which the deflection is calculated from the measured strain data and displacement-strain relationship [1,2]. In this way, however, the calculated displacement from strain data is sensitive to noise, and the sensors are expensive and must be embedded into the structure, which to a certain degree is difficult for bridges in service. To cope with those inconveniences in contact measuring methods, various non-contact approaches have been proposed. Based on the detection of the Doppler shift of the laser light, a laser Doppler vibrometer (LDV) equipped with displacement and velocity signal decoders can measure both bridge deflection and vibration simultaneously [3]. In this way, a static reference point (usually underneath the bridge) is needed for device mounting, and the device should be attended, which limits it’s usability for long-term monitoring. Among image methods, dynamic deflection with high resolution of the bridge can be obtained through using digital image processing techniques [4], while deflection distribution from the images of the bridge girder surface recorded by a digital camera before and after deformation can be evaluated by digital image correlation techniques [5], and digital close-range terrestrial photogrammetry (DCRTP) can measure the spatial coordination in three-dimensions [6,7]. Like the LDV, devices such as video cameras used in image methods cannot be left unattended and they are easily affected by weather conditions. Use of a Global Positioning System (GPS) can provide spatial locations of the measuring points on the bridge in real-time by comparing with a continuing operational reference station (CROS). It offers a long-term monitoring approach without being affected by climatic factors [8,9], but due to its relatively low accuracy, it is only applied to those bridges with significant deformations. All the non-contact methods mentioned above, although they differ in instrumentation, have one thing in common, a static reference point or CROS that is kept a certain distance away from the bridge is selected for installation of the measuring device, otherwise measurements cannot be carried out. Another method is using inclinometers which can be installed on the bridge directly along a line paralleling the bridge span axis [10,11], and both static and dynamic deflection time history curves can be calculated through curve-fitting technology based on the accurate angle records of the inclinometers. An outstanding feature of the inclinometer is that static reference Sensors 2012, 12 9989 points mentioned above are no longer needed. This approach reduces the dependence on environmental conditions and it is suitable for long-term monitoring. To avoid those deficiencies in conventional estimating deflection methods mentioned above, a novel three-point deflection estimation method is presented in this paper. Measuring points along lines paralleling the bridge span axis are chosen equidistantly. Among these measuring points, every three adjacent measuring points are defined as a measuring unit in which a straight connecting bar linking the two endpoints is taken as a relative reference line. Relative deflection of the mid-measuring point relative to the intermediate point of the connecting bar on which a displacement sensor is fixed can be measured, and thus the absolute deflection of each measuring point can be calculated from the relative deflections of all the measuring units. Compared with the contact and non-contact methods mentioned above, only real spatial positions of the measuring points are taken as relative references without any other static reference points. Moreover, the selected displacement sensor is the grating eddy current absolute position sensor (GECS) which is different from traditional eddy current sensors based on vertical characteristics [12,13]. Since the structure of grating reflective conductors is adopted, the measurement range is extended but without compromising the accuracy. In addition, as an inductive sensor, the GECS is waterproof and dustproof in principle, thus it can work under bad weather conditions, which makes it ideal for long-term monitoring. In this paper, both the principles of the three-point method and displacement measurement of the GECS are presented. Then, this three-point method for deflection estimation is verified in a simply supported girder bridge model in the laboratory. Comprehensive static and dynamic experiment results on the laboratory tests demonstrate this method is effective and offers an alternative way for bridge deflection estimation.