Hm..sebuah topik yg cukup relevan pada masa sekarang. Terutama jaman teknologi komputer dan informasi sedang hebat2nya seperti sekarang. Kebanyakan manusia sudah mulai terasa bergantung kepada kehebatan teknologi ini. Termasuk mungkin kebanyakan engineers era milleneum. Loh..emang kenapa bro? What is wrong ?
Nothing wrong bro. Ini sekedar sharing atau lebih tepatnya intropeksi buat gue bahwa kita perlu merenungi lagi profesi kita sebagai engineer, kaitannya dengan alat bantu kita yg sungguh hebat dalam rungan kerja kita sehari-hari yaitu komputer dan software2 disain (dalam bidang struktur) seperti SAP2000, STAADPro, ANSYS, ABAQUS, SACS dll.
Sebenarnya bukan teknologi komputernya yang perlu diwaspadai/ditakutkan. Tetapi justru pada orang yang mengoperasikan/menggunakannya. Ada istilah paling terkenal mengenai hal ini : "garbage in...garbage out", kurang lebih artinya : sampah yang masuk...maka sampah juga yang keluar.
Yang diperlukan disini adalah pemahaman konsep2 dasar yang dulu kita pelajari waktu di kuliah seperti mekanika teknik dan bahan (baja/beton/kayu). Dengan pegangan pada pemahaman yg benar akan konsep2 dasar itu, maka insyaAllah kita tidak tersesat atau terlena di lembah simulasi software2 canggih itu.
Kalo ada engineer2 senior/sepuh yg complain: "ah..payah, engineer2 sekarang kurang banget "feeling" buat perilaku struktur. Lah...bikin disain di SACS cepat banget selesainya. Bikin report sampai bagus banget lampirin snapshot resultnya. Tapi dia kok gak sadar kalo resultnya itu jelas2 salah". Lalu sang senior engineer melanjutkan: Dulu jaman saya kalo mendisain pake tulisan tangan, pake metoda distribusi momen, jadi bisa punya feeling sama struktur yang didisain.
Hehehe...kira2 seperti itulah kisahnya.
Hm...kalo engineer muda tadi punya strong understanding tentang basic2 structural behaviour seperti yang gue bilang tadi, sebenarnya menurut gue justru engineer muda lebih hebat! Loh..kok bisa ??
Karena justru dengan adanya komputer yg super cepat seperti sekarang dengan software2 disain yang hebat seperti SACS atau ANSYS....sepatutnya the young generation engineer bakal punya "feeling much better for structural behaviour" daripada sang senior tadi yang komplain. Karena dengan kecepatan komputer sekarang, lebih banyak simulasi rekayasa yang bisa dilakukan untuk melihat berbagai macam perilaku2 struktur. Coba kalo pake hitungan tangan, ngitung jacket di water depth 70 meter yang punya banyak X-braces dan perlu dicek pada berbagai kondisi seperti minimum water depth + minimum payload, minimum water depth + maximum payload, etc. Wah...bisa berabe si senior menyelesaikannya kalo pake hand calculation bukan ?
Secara singkat, dalam suatu "analisis struktur" sebenarnya ada tiga tahapan penting. Yaitu tahap "MODELLING", lalu tahap "Number Crunching" dan terakhir adalah tahap "INTERPRETATION".
Nah...mungkin sindiran senior/sesepuh engineer diatas tadi sebenarnya ditujukan pada engineer2 muda yg cuman jago di "Number Crunching" (manipulasi numerik/angka), yang mungkin juga dialami si engineer muda waktu di kampusnya dulu. Bisa jadi pendidikan kita sekarang banyak difokuskan pada aspek "Number Crunching" namun sedikit/kurang pada aspek "Modeling" dan "Interpretation" yang sebenarnya sangat penting dalam dunia kerja. Sebab detail2 perhitungan secara relatif tidak begitu dituntut, namun asumsi2 yg digunakan dalam analisis model dan apa maksud hasil analisisnya in term of behaviour and performance...nah ini yang paling penting !
Selanjutnya, gue kutip dari sini : http://www.structuremag.org/article.aspx?articleID=798
mengenai ketiga aspek penting dalam pekerjaan seorang structural engineer.
What is "Modeling"?
It may seem obvious,
but it is worth keeping in mind that we analyze a model of a structure, not the
structure itself, and that the behavior of the model may or may not be close to
the behavior of the actual structure. The challenge is to create a model that
is accurate enough for practical purposes.
To create a meaningful model an engineer must (1) understand the
behavior of the components that make up the structure, and (2) know how to
capture the important aspects of this behavior in an analysis model. This is
not a simple task. It requires an understanding of such things as axial and
shear forces, bending and torsional moments, beam and column behavior, load
transfer through connections, connection deformations, composite action,
cracking, yield, bolt and bond slip, buckling, and many other aspects,
including the difference between actual and design loads. It then requires
decisions on how (or whether) to model different aspects of behavior, given the
capabilities of the available analysis methods (or computer programs). Modeling
is especially difficult for nonlinear analysis, because of the many types and
causes of nonlinear behavior. It is also more difficult for dynamic loads.
An important skill for an analyst is the ability to create useful models
of real structures (not just simple two-dimensional frames of the type that are
often considered in analysis courses). A useful model must capture the behavior
of the structure with sufficient accuracy for design purposes, it must produce
results that are accurate enough for making design decisions, and it must not
be so large or complex that it takes too long to analyze. A model does not have
to be, and never can be, "exact".
What is "Interpretation"?
There are two parts
to interpretation, namely (1) checking the analysis results to make sure that
they are reasonable, and (2) organizing the results in a form that supports
decision making for design.
Checking analysis results requires a number of skills. There are several
tools that can be used, including free bodies and equilibrium equations, and
methods for checking displacement compatibility. Common sense and a feel for
structural behavior are indispensable. Experience is always valuable.
Organizing the results requires an understanding of how analysis results
are used for assessing performance and making design decisions. Almost always,
design decisions are made using strength and/or deformation demands,
corresponding capacities, and hence Demand/Capacity ratios. In the analysis of
a frame structure, the deflected shape and the bending moment diagram are
useful for checking the analysis results. They are not particularly useful for
assessing performance or making design decisions.
What is "Number Crunching"?
The number crunching
phase is everything that is not included in the modeling and interpretation
phases. It includes the numerical computations and the underlying theory.
