I am the author of a methodology for Analysing and Sinthesis of Engineering Systems, that includes two optimization methods: Selection of Proposals and the Integration of Variables Methods. Most of my works are writen in Spanish. Please find attached a brief description in English Lenguage.

Actually, the techniques that are recently used for optimization are in fact the same that were used some 10-20 years ago. The main difference is, however, that computers are way more powerful today in terms of main memory and speed (and number of cores). Although scientist gained a deeper understanding of the methods they used, so that they can be much better tailored to a certain application. To give a very brief survey (in fact, just a name-dropping), we have heuristic methods such as Genetic Algorithms or Simulated Annealing, and a whole bunch of mathematical optimization techniques for linear, nonlinear, mixed-integer, differential-equation-constrained, stochastic, robust, multi-criteria, multi-level optimization, that is applied - among other areas - also to engineering problems.

As was mentioned by Armin, optimization techniques are basically the same as 10-20 years ago. More or less recent trend is a combination of different approaches, the so called hybrid techniques. For example, using heuristics (metaheuristics) inside exact optimizations schemes to speed up the convergence. Alternatively, exact methods can be adjusted in a heuristic manner to cover non standard applications.