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Henry Petroski《工程、設計與人性》(To Engineer Is Human);“牙籤: The Toothpick: Technology and Culture”,書評

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Henry Petroski 的書都值得一讀。




高雄氣爆事件,以及飛機空難,這類工程事故或許可以歸結到一些最常見的工程問題—&...
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  高雄氣爆事件,以及飛機空難,這類工程事故或許可以歸結到一些最常見的工程問題, 也就是失效(failure),以及疲勞(fatigue)。

原本,工程設計的首要目標,就是避免「失效」: 希望結構體可以依預期而運作,直到結構壽命終了為止。然而,如果管線因為金屬疲勞等原因,而產生裂縫,裂縫不斷擴大,到結構難以支撐,最嚴重的會造成斷裂,這就是工程的失敗或失效,也是工程設計上竭力要避免的情況。

高雄氣爆,應是和管線洩漏有關,而裂縫(crack)的產生,通常是工程意外的開始。

還有,環境也是決定結構安全的重要因素。你無法建一座和以往成功經驗一模一樣的橋,在同一個地方,因為即使地點不變,時間、土質、天候都會不同。因此即使是最保守的設計師,完全師法過去安全的設計,也難以完全避免意外發生。這說明了為什麼工程意外的機率要降到0是如此困難的原因。

這是Henry Petroski所著的《工程、設計與人性》(To Engineer Is Human這本書告訴我們的事。這本書就是環繞著工程失效、結構體、疲勞失效的問題,以及工程師如何與天為敵、設法克服環境與大自然的限制,設計出以前不存在的東西的努力。每當發生工程意外,或許就凸顯了這本書的重要性,但願工程師們、設計者、管理者能夠記取史上的災難教訓,繼續前進。

裂縫問題,可參考這本書的第10章「當裂縫造成突破」及第11章「公車骨架與刀身」;飛機的結構失效問題,可參考第14章的「鑑識工程與工程小說」。以下摘錄第10章「當裂縫造成突破」的部分內容:

一般認為,包括鐘、橋梁、飛機,還有其他常見的科技產物,有50%90%的結構失效都是由於裂痕擴大所引起。而在大多數狀況下,裂痕都是慢慢擴大的。唯有當裂痕大小達到結構所無法承受的地步,但仍無人察覺時,災難才會發生。因此,裂痕本身未必是災難的原因,而負責任的工程設計會事先考慮到,在設計的物品上會出現裂痕,或其他材料、做工的瑕疵。在整個產品使用期間,這些瑕疵對於結構的影響,都應該在設計當中加以計算,而工程師則可以提醒結構體的業主與操作者,要隨時謹防日益擴大的裂痕,因為計算也可能有誤差。
  好幾個世紀以來,大裂痕自發地以接近音速的速度貫穿結構體的「脆性斷裂」(brittle fracture),一直是個揮之不去的問題。而導致鋼鐵斷裂的「脆性斷裂」,則是船身瓦解、壓力槽爆裂,或是橋梁坍塌的前奏。在災難發生前,幾乎總是有「醞釀期」,這時裂痕會在疲勞的過程中,逐漸變得更長、更嚴重。卡爾.奧斯古(Carl Osgood)在專書《疲勞設計》(Fatigue Design)中,甚至大膽斷言:「由於自然力不斷在運作,每個物體都必須以某種方式回應,而一切機械與結構設計的問題都出在疲勞上。」
  在金屬微結構上,雖然有包括精心假設的例外,或是「差排」(dislocations)等等好幾種冶金理論,來解釋漸進式疲勞損壞的機制,但沒有一種解釋令人完全滿意。然而,就在冶金學家彼此討論,某塊金屬究竟是如何斷裂的精確細節時,卻不斷有人要求工程師,設計出縱使承受極度震動,還有其他種種負荷,也不會斷裂的機器與結構體。因此,工程師為了能預測裂痕擴大的速度,還有它們能擴大到什麼程度而不導致失效,都必須發展出實務方法。通常也是透過這些考量,來設定結構體預計有效使用的期限。
  數十年來,結構工程師們一直認為,疲勞過程實質上是由兩個階段構成的。在第一個階段中,細微的裂痕會在「成核點」(nucleation sites),也就是材料弱點或應力集中點產生,而在機件或結構體的整個使用期限裏,這個階段便可能佔了一半之多。隨著負載周而復始,這些裂痕也逐漸產生,而若干裂痕「合縱連橫」,形成顯著而粗大的疲勞裂痕。接著在第二個階段中,隨著負載循環持續,這裂痕也加速擴大。要是裂痕因承受的負荷而變得太大,弱化的結構體可能就再也承受不了。這時候,即使其負荷量還在設計的範圍內,裂痕卻會壓垮了最後一道防線。
  冶金學家往往憑經驗學會,如何製作成核點盡可能少,而抗裂痕擴大力盡可能強的合金。而工程師則學會加強接頭,以降低局部負荷量,同時使用具有高抗裂力,並不會產生脆性斷裂的材料。不過,由於無論是冶金學家或工程師,都只是根據以往有限的經驗,去預測在未來不確定的環境下,前所未見的新材料經使用與濫用時會有什麼樣的行為,因此,金屬疲勞的問題依舊存在。而在新設計中,即使與經驗只有些微的差異,也可能造成意外的後果。
  而了解疲勞現象和加以預防,是截然不同的兩件事。有關裂痕產生的假設,是在實驗室中理想、受控制的狀態下測試的。為了盡量提供完美的表面,你可以精心按既定的尺寸製作試樣,而載重狀態也能仔細地加以規定並監控。由於在這種狀況下,試驗結果是可以重複的,因此代表重複載重或重複應力的平滑曲線(工程師通常以字母S標示),還有相對的疲勞失效周期數(以字母N標示),都能輕易做出來。而這些S-N曲線所呈現的,正是每種材料的行為特性。當然,隨著應力降低,失效周期數便會增加,也就是結構體的「壽命」便會拉長。此外,要是負載量降到某個門檻值以下,無論歷經多少次負載周期,你都不會觀察到失效。
  這樣一來,理論上便能夠避免疲勞,但若是為了確保最高應力絕不會超過門檻值,而去設計超安全的結構體,那是不實際的。用那種方式設計的飛機可能太重,以致飛不起來;即使它飛得起來,製造對手不久也會設計出能以較低成本建造、銷售並營運的更輕機型。而在最佳設計中,疲勞與裂痕雖然必定會變本加厲,但其速度之緩慢,早在裂痕形成任何安全問題前,這個結構已可以退役了。然而這種最佳設計,構想容易做起來難。

工程、設計與人性:為什麼成功的設計,都是從失敗開始? 
To Engineer Is Human: The Role of Failure in Successful Design 
 亨利.波卓斯基(Henry Petroski◎著 
楊幼蘭◎譯 
2014年6月25日出版
QB1115
 


牙籤
Henry Petroski 的"小東西群眾運動"台灣翻譯了約2/3
這篇提到晚近許多本"旁門左道"談文明的通俗名著 中文可能翻譯一半強

可以把這篇當學習英文的讀物 有空再注

Essay

Consider the Toothpick


Illustration by Stephen Savage


Published: October 28, 2007

From time to time, society itself is called upon to intervene when someone it admires goes astray. Whether it is rehab for Lindsay Lohan or a decisive thumbs down to Michael Jordan’s ancillary baseball career, we must periodically take our brightest stars aside and read them the riot act. No, we do not want any more songs like “Dandelions Don’t Tell No Lies.” No, we do not want any more movies like “Battleship Earth.” No, we will not be requiring your services as talk-show hosts, the Messrs. Chase and Sajak.
In a loftier milieu, such intervention may now be required in the case of the redoubtable Henry Petroski. A professor of civic engineering and history at Duke University, Petroski has made quite a name for himself by publishing a series of delightful books in which he explores the history of such indispensable yet taken-for-granted devices as the pencil, the flashlight, the doorknob and the kitchen sink. These exhaustively researched, disarmingly affectionate books celebrate the genius of the quotidian, the elegance of the functional, the romance of the ubiquitous.
But now, with the publication of “The Toothpick: Technology and Culture” (Knopf, $27.95), Petroski is literally tossing in the kitchen sink he has previously only written about. Originally projected as a single chapter in an earlier book, in which the “engagingly simple device ... would serve to illustrate some basic principles of engineering” and “help reveal the inevitable interrelationships between technology and culture,” “The Toothpick” swelled into a 443-page tome that (unlike the object it concerns) fills a need that does not exist, sealing up a void whose vacuity was a source of distress to no one. It is not so much a book as a threat: If you liked “The Toothpick,” wait till you get a load of “The Grommet.” If “The Pencil” was Petroski’s Sudetenland and “The Evolution of Useful Things” his Anschluss, then “The Toothpick” can only be characterized as his invasion of Poland. And just as France and England were compelled to belatedly intervene back then, literate, sane people must now step into the breach. This thing about things has gone far enough, Mr. Petroski. Knock it off.
The very existence of “The Toothpick” is a testimony to the perils of inhabiting a permissive society, for just as the unchastised teenage shoplifter, mistaking society’s indulgence for applause, will evolve into a bloodthirsty hired killer, it is inevitable that the author of “The Pencil” will one day morph into the author of “The Toothpick.” Quite rightly, he assumes that society is simply not paying attention anymore.
“The Toothpick” is animated by the dubious proposition that the venerable mouth-cleaning device in and of itself is worthy of our consideration. Yet, as Petroski himself admits: “With a toothpick, what we see is what we’ve got — inside a toothpick is the same wood that we see on the outside.” Despite amusing anecdotes about the preposterously gauche Roman emperor Nero turning up at a feast with a silver toothpick dangling from his lips, and the novelist Sherwood Anderson fatally puncturing his liver with a toothpick buried inside an olive, none of this makes the toothpick itself any more riveting: John Wilkes Booth is interesting, not his pistol.
Asserting that “picking one’s teeth is believed to be the oldest human habit,” Petroski suggests that the toothpick may be two million years old. Be that as it may, the toothpick cannot hold a candle to the much younger fork or spoon, and finishes far out of the money behind such ingenious inventions as the laptop computer and the iPod. The toothpick is perhaps slightly more interesting than the staple, the washer and the index card, somewhat less fascinating than the screw or the bolt, but infinitely less exciting than the hydrogen bomb, the semiconductor chip or the microbe. The toothpick lacks the anthropological panache of the toupee, the bustle or the collateralized mortgage obligation, the flash and brio of the cuirass or the monstrance, the epochal influence of the stirrup, the shoelace, the ace of spades and the espresso machine, and it most assuredly cannot lay claim to the esoteric charm of the baritone saxophone and the tea cozy, much less the enduring mystery of the French maid’s flouncy apron. Petroski has mistakenly assumed that merely because he could assemble a huge amount of information about the rise and fall of the toothpick industry, such data was worth compiling in a 443-page book. Did you know that boxes of early machine-made toothpicks were labeled with “a caveat about imitators” to prevent consumers from falling prey to 19th-century gray-market toothpicks? Or that a remarkable Norwegian transplanted to Duluth once patented a toothpick dispenser “mounted on the back of a stylized metal turtle”?
Reviewers of “The Toothpick” will automatically lump Petroski’s work in with “Salt,” “Cod,” “How Soccer Explains the World,” “A History of the World in Six Glasses” and other volumes that view society through an odd prism. These books argue that without cod, salt, booze or the penalty kick, we would not be where we are today. This is true, though the same could be said about tuna, cocaine, beavers, coriander, the infield-fly rule and the “going out of business” sale. These books settle arguments no one is having. It’s like writing a book called “How Annoying Roommates Changed the World.” Yes, annoying roommates — Robespierre, Marlon Brando, Al Gore— have changed the world. So what?
Moreover, comparing “The Toothpick” to these other works is inappropriate. Books of the “How Longitude or Beer or the Irish or Something Changed Civilization” sort are mostly the work of journalists. No strangers to harmless hyperbole, these writers desperately want to close the deal but are aware that unless they keep hawking their wares, the reader may nod off. So they never stop with the balloons and the firecrackers, never stop pushing the merchandise. That’s why their books are fun to read.
“The Toothpick,” by contrast, is the work of a maddeningly sober pedant who is anything but a crowd pleaser. “It would appear that in America the use of toothpicks has become largely a matter of class,” he writes in a passage that expertly captures his infatuation with the obvious and the insignificant. “Unlike in the late 19th century, when the urbane crutch-and-toothpick brigade proudly chewed its toothpicks on the steps of fine hotels and restaurants, now it is more the rural and less educated who openly chew theirs in the parking lots, if not at the counter itself, of big-box stores and fast-food establishments.”
Where books like “Guns, Germs and Steel” or “Rats, Lice and History” examine overlooked trends or inventions and demonstrate the decisive role they have played, “The Toothpick” is basically a paean to our irrepressible friend, the toothpick. Petroski assumes that once they have overcome their initially blasé attitude, people will be mesmerized by the tale of how an inexpensive oral-particle-removing device came out of nowhere to take the world by storm. He has forgotten the hoary dictum: Never send a toothpick to do a pencil’s job.
It’s possible that “The Toothpick” is inspired satire, a deliciously subtle send-up of a genre Petroski helped to popularize. A more plausible explanation is that the author was so emboldened by the public’s giddy response to his earlier work that he decided to go for broke. If this is the case, then we, the reading public, bear the greatest responsibility for this misfortune.
There is no telling where he will strike next. But an ominous hint of his intentions is contained in the preface, where he writes: “I have never been a regular user of toothpicks, though there has always been a box or two of the little wooden things about the house. Occasionally they have come in handy for applying a dab of glue or oil to a small part, cleaning dust out of a tight crevice, plugging up an empty nail hole or two, serving as shims, testing the doneness of a batch of brownies and the like.”
If Petroski is already fulfilling one clever historian’s prophecy that as academics retreat from the world writ large, they will teach us more and more about less and less, it is safe to suppose that his next books will include such titles as these: “The Dab: A Closer Look,” “The Shim That Time Forgot: A Short History of Those Little Wooden Things” and “Dust and the West.”
All of which would be merely a warm-up for “The Doneness of Brownies.”

Joe Queenan writes for Barron’s, The Guardian, Men’s Health and The Weekly Standard.



Henry Petroski 的書評
  • An Inventive Hollywood Star

    "Hedy's Folly" chronicles important moments in the filmstar's life—from filming nude scenes for 'Ecstasy' in 1933 to devising radio-controlled torpedoes meant to foil German defenses in World War II. Henry Petroski reviews.
  • [bkrvestonia]
December 16, 2011
In his new book, Richard Rhodes, the author of acclaimed histories of the atomic and hydrogen bombs, tells the story of a 1940s Hollywood bombshell and her fascination with military-weapon design. Yet even though "Hedy's Folly" ostensibly concerns, as the subtitle has it, "the life and breakthrough inventions of Hedy Lamarr, the most beautiful woman in the world," the book is equally about the role that chance and coincidence can play in the development of technology.
Hedy Lamarr, born Hedwig Kiesler in Vienna in 1913, was the only child of Jewish parents. Emil Kiesler, a successful banker, was a doting father; her mother, Trude, a former concert pianist, was less indulgent, "concerned that such a pretty, vivacious child would grow up spoiled unless she heard criticism as well as compliments," Mr. Rhodes writes. Trude taught Hedy to play the piano, and Emil conveyed to his daughter a consuming interest in technology.
Hedy dropped out of high school at 16 to pursue an acting career in Berlin. At 18, after appearing onstage and in a few small film roles, she was cast by Czech director Gustav Machaty as the lead in "Ecstasy," a movie that contained two brief nude scenes and much sexual symbolism. Even though she was billed by her real name—the change to Hedy Lamarr would come in Hollywood—her association with a movie so daring for its time would, the author says, "both promote and plague her professional career."
The actress captured the attention of Fritz Mandl, a wealthy and powerful Austrian arms manufacturer. After she married him at age 19, her new husband tried, unsuccessfully, to buy up every print of "Ecstasy" so that no one else could ever view it again. As Mandl's wife, hosting dinner parties for his business associates, Hedy became familiar with the technology of war. Like much of this most unusual book about a Hollywood star, Mr. Rhodes relates the Austrian chapter of Lamarr's story with engaging efficiency.
As Europe in the mid-1930s was roiled by Hitler's rise, Lamarr, a Jew, resolved to flee her homeland and her marriage. Her controlling husband had Jewish roots—his father had converted to Catholicism, his wife's religion—but Mandl was also a proponent of fascism. In London, the actress met the MGM studio chief Louis B. Mayer, who signed her to a contract and insisted on a new screen name. The rest is Hollywood history—with a twist.

Hedy's Folly

By Richard Rhodes
(Doubleday, 261 pages, $26.95)
As Mr. Rhodes relates, Hedy Lamarr was hardly an intellectual, but she was a indefatigable tinkerer. Among her inventions was a sort of bouillon cube that, when dissolved in water, produced a cola-like drink. Another was an attachment for a tissue box to hold used tissues, a convenience that anyone with a bad cold can appreciate. But she also turned her attention beyond the domestic. Even as she was starring in movies such as "Boom Town" (1940), Lamarr applied her inventing talents to trying to combat German submarines preying on ships in the North Atlantic. She had an idea for radio-controlled torpedo delivery that could not be foiled by the enemy.
Enter George Antheil, an American avant-garde composer whose works were known for using unorthodox instruments such as player-pianos, airplane propellers and sirens. He also wrote music for movies and, like Lamarr, tinkered with ideas for inventions. His signature composition from the 1920s, "Ballet Mécanique," prompted him to develop a way to synchronize multiple player-pianos.
Ever scrambling to piece together an income, Antheil wrote frequently for Esquire magazine—including articles on endocrinology, particularly female hormones, that happened to catch Lamarr's attention. The actress told a friend who knew Antheil that she would like to meet him. When they were introduced at a dinner party in August 1940, she asked Antheil if he knew how she might make her breasts bigger. Mr. Rhodes reports that Antheil recalled, in his autobiography, "Bad Boy of Music," suggesting "various glandular extracts" that would help the pituitary gland, with the added benefit that "the bosoms stay up."
Antheil and Lamarr eventually moved on to talking about the war in Europe. She wondered if her knowledge of munitions and secret weapons projects from her time in Austria could help somehow. She also described an idea for a remote-controlled torpedo: A radio transmitting directions and a receiver implementing them would be synchronized so that their frequencies could be changed simultaneously in a random manner. This constant retuning would make it difficult for the enemy to jam the signals. Lamarr termed the technique "frequency hopping," a forerunner of the spread-spectrum technology that is used today in communications applications such as Wi-Fi.
Antheil lent his experience with synchronizing player pianos. The two refined the idea, then consulted with an electrical-engineering professor at the California Institute of Technology, who confirmed that the concept would work. U.S. Patent No. 2,292,387 for a "Secret Communication System" was issued to Hedy Kiesler Markey and George Antheil in 1942. (Markey was the surname of a husband she had divorced in 1940.) The frequency-hopping technology was not put to use in World War II, but it was employed in 1962 during the blockade of Cuba.
Today, when innovation is often identified as essential for revitalizing an ailing economy, politicians demand more science funding as an incentive. They would do well to note the story of Hedy Lamarr and remember that innovation comes in many forms, often from unlikely sources, who all have one thing in common: a love for ideas and an urge to find out if they'll work.
Mr. Petroski is a professor of engineering and of history at Duke University. His latest book is "An Engineer's Alphabet: Gleanings From the Softer Side of a Profession."

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